Indonesia in Focus: Unfinished journey (28)

Wind energy

Unfinished journey (28)

(Part duapuluhdelapan, Depok, West Java, Indonesia, September 2, 2014, 6:25 pm)

In 1995 I was a senior journalist with Radio Republik Indonesia (RRI) Ahmad Parembahan covering Energy World Conference held in the city of Madrid, Spain,

The conference opened Spanish King Juan Carlos Queen Sofia was accompanied attended by thousands of delegates from over 100 countries who discuss energy problems of the world, such as petroleum, coal, natural gas, and alternative energy such as geothermal energy, solar energy, hydropower, wave and various other alternative energy such as bio-diesel.

From Indonesia Prof.Dr.Zuhal represented at the conference, and the expert staff of the Minister of Mines and Energy Ermansyah Yamin.

In the conference illustrated how much consumption, and the availability of energy reserves such as oil, coal, natural gas and other alternative energy.

As well as how to maintain a balance between consumption and exploration of search for available resources, as well as discuss the use of new technology that allows the use of coal for power generation, but using technology to filter the smoke does not cause environmental pollution (acid rain). Paper presented also includes the issue of geothermal energy, wind power and solar energy.

Geothermal Energy

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Geothermal energy is heat energy contained and are formed in the earth's crust. Temperatures below the Earth's crust increases with increasing depth. The temperature at the center of the earth is estimated to reach 5400 ° C. According to Article 1 of Law No.27 of 2003 on Geothermal Geothermal energy is the heat contained in the hot water, water vapor, and associated minerals and rocks along with other gases that are genetically all can not be separated in a Geothermal system and to utilization required the mining process.

Geothermal energy is derived from within the earth's tectonic activity that occurred since the planet was created. This heat also comes from the sun's heat is absorbed by the earth's surface. In addition, geothermal energy is thought to originate from several phenomena:

Decay of radioactive elements in the earth's subsurface.

The heat given off by heavy metals due to sink into the center of the earth.

Electromagnetic effects are influenced by the Earth's magnetic field.

This energy has been used to heat (the room during the winter or water) from the Roman civilization, but is now more popular for generating electrical energy. Approximately 10 gigawatts of geothermal power plants have been installed worldwide in 2007, and accounted for about 0.3% of total world electricity.

Geothermal energy is quite economical and environmentally friendly, but limited to areas near tectonic boundary layer.

Prince Piero Ginori Conti try first geothermal generator on 4 July 1904 in Larderello geothermal area in Italy. Group geothermal resource areas in the world, called The Geysers, located in Iceland, the north pole. In 2004, five countries (El Salvador, Kenya, the Philippines, Iceland, and Costa Rica) have used geothermal energy to produce more than 15% of its electricity needs.

Geothermal power plants can only be built around the tectonic plates where high temperature geothermal sources available near the surface. Development and improvements in drilling and extraction technology has expanded the reach of the construction of a geothermal power plant from the nearest tectonic plate. The thermal efficiency of thermal power plants umi tend to be low because the geothermal fluid is at lower temperatures compared to steam or boiling water. Based on the laws of thermodynamics, the low temperature limit the efficiency of the heat engine takes energy for generating electricity. Residual heat wasted, unless it can be used locally and directly, eg for heating the room. The efficiency of the system does not affect operational costs such as power plants for fossil fuels.

Geothermal and Power Operations ListrikOperasi Geothermal and Renewable Energy Clean Energy ListrikMenyediakan with Affordable Price

Chevron is the largest geothermal energy producer in the world and has operations in Indonesia. Geothermal energy is produced from heat emanating from the bowels of the earth. This energy is capable of producing reliable electricity without greenhouse gas effect.

Subsidiary Chevron Geothermal operates two geothermal projects in Indonesia - Darajat and Salak - both located on the island of Java. Darajat provide geothermal energy projects, which are able to generate electricity with a capacity of 259 megawatts. The entire electricity generated from operations Darajat sold directly to the national electricity demand. Chevron has a 95 percent ownership in Darajat operation.

We Geothermal Operations

More than 30 years Chevron has been a leader in the development of geothermal energy and our operations in Darajat and Salak represents about 50 percent of the production of geothermal energy in Indonesia.

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Chevron owns and operates projects Salak. Geothermal operations is one of the largest in the world, with a total operating capacity reaches 377 MW.

The combined results of operations Darajat and Salak geothermal is now able to produce enough renewable energy to the needs of about 4 million homes in Indonesia.

Chevron also operates and has a 95 percent ownership in North Duri Cogeneration power plant in Sumatra, which provide up to 300 megawatts of electricity and steam requirements for the CPI to support the CPI steam injection project in Duri.

Chevron has a 95 percent ownership and operating permits in Suoh-Sekincau prospects in southern Sumatra. The Indonesian government has issued a permit to Chevron to develop the region, and we have started the initial steps through geological and geophysical surveys. If successful, this project will be able to provide additional power capacity of 200 megawatts in Chevron's geothermal portfolio.

GEOTHERMAL ENERGY

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Steam rising from the Nesjavellir Geothermal Power Station in Iceland.

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Geothermal energy is thermal energy generated and stored in the Earth. Thermal energy is the energy that determines the temperature of matter. The geothermal energy of the Earth's crust originates from the original formation of the planet (20%) and from radioactive decay of minerals (80%).[1][2] The geothermal gradient, which is the difference in temperature between the core of the planet and its surface, drives a continuous conduction of thermal energy in the form of heat from the core to the surface. The adjective geothermal originates from the Greek roots γη (ge), meaning earth, and θερμος (thermos), meaning hot.

Earth's internal heat is thermal energy generated from radioactive decay and continual heat loss from Earth's formation.[2] Temperatures at the core–mantle boundary may reach over 4000 °C (7,200 °F).[3] The high temperature and pressure in Earth's interior cause some rock to melt and solid mantle to behave plastically, resulting in portions of mantle convecting upward since it is lighter than the surrounding rock. Rock and water is heated in the crust, sometimes up to 370 °C (700 °F).[4]

From hot springs, geothermal energy has been used for bathing since Paleolithic times and for space heating since ancient Roman times, but it is now better known for electricity generation. Worldwide, 11,400 megawatts (MW) of geothermal power is online in 24 countries in 2012.[5] An additional 28 gigawatts of direct geothermal heating capacity is installed for district heating, space heating, spas, industrial processes, desalination and agricultural applications in 2010.[6]

Geothermal power is cost effective, reliable, sustainable, and environmentally friendly,[7] but has historically been limited to areas near tectonic plate boundaries. Recent technological advances have dramatically expanded the range and size of viable resources, especially for applications such as home heating, opening a potential for widespread exploitation. Geothermal wells release greenhouse gases trapped deep within the earth, but these emissions are much lower per energy unit than those of fossil fuels. As a result, geothermal power has the potential to help mitigate global warming if widely deployed in place of fossil fuels.

The Earth's geothermal resources are theoretically more than adequate to supply humanity's energy needs, but only a very small fraction may be profitably exploited. Drilling and exploration for deep resources is very expensive. Forecasts for the future of geothermal power depend on assumptions about technology, energy prices, subsidies, and interest rates. Pilot programs like EWEB's customer opt in Green Power Program [8] show that customers would be willing to pay a little more for a renewable energy source like geothermal. But as a result of government assisted research and industry experience, the cost of generating geothermal power has decreased by 25% over the past two decades.[9] In 2001, geothermal energy cost between two and ten US cents per kWh.[10]

Contents [hide]

1 History

2 Electricity

3 Types

3.1 Liquid-dominated plants

3.2 Thermal energy

3.3 Enhanced geothermal

4 Economics

5 Resources

6 Production

7 Renewability and sustainability

8 Environmental effects

9 Legal frameworks

10 See also

11 References

12 Bibliography

13 External links

History[edit]

The oldest known pool fed by a hot spring, built in the Qin dynasty in the 3rd century BCE.

Hot springs have been used for bathing at least since paleolithic times[11] The oldest known spa is a stone pool on China's Lisan mountain built in the Qin Dynasty in the 3rd century BC, at the same site where the Huaqing Chi palace was later built. In the first century AD, Romans conquered Aquae Sulis, now Bath, Somerset, England, and used the hot springs there to feed public baths and underfloor heating. The admission fees for these baths probably represent the first commercial use of geothermal power. The world's oldest geothermal district heating system in Chaudes-Aigues, France, has been operating since the 14th century.[12] The earliest industrial exploitation began in 1827 with the use of geyser steam to extract boric acid from volcanic mud in Larderello, Italy.

In 1892, America's first district heating system in Boise, Idaho was powered directly by geothermal energy, and was copied in Klamath Falls, Oregon in 1900. A deep geothermal well was used to heat greenhouses in Boise in 1926, and geysers were used to heat greenhouses in Iceland and Tuscany at about the same time.[13] Charlie Lieb developed the first downhole heat exchanger in 1930 to heat his house. Steam and hot water from geysers began heating homes in Iceland starting in 1943.

Global geothermal electric capacity. Upper red line is installed capacity;[14] lower green line is realized production.[6]

In the 20th century, demand for electricity led to the consideration of geothermal power as a generating source. Prince Piero Ginori Conti tested the first geothermal power generator on 4 July 1904, at the same Larderello dry steam field where geothermal acid extraction began. It successfully lit four light bulbs.[15] Later, in 1911, the world's first commercial geothermal power plant was built there. It was the world's only industrial producer of geothermal electricity until New Zealand built a plant in 1958. In 2012, it produced some 594 megawatts.[16]

Lord Kelvin invented the heat pump in 1852, and Heinrich Zoelly had patented the idea of using it to draw heat from the ground in 1912.[17] But it was not until the late 1940s that the geothermal heat pump was successfully implemented. The earliest one was probably Robert C. Webber's home-made 2.2 kW direct-exchange system, but sources disagree as to the exact timeline of his invention.[17] J. Donald Kroeker designed the first commercial geothermal heat pump to heat the Commonwealth Building (Portland, Oregon) and demonstrated it in 1946.[18][19] Professor Carl Nielsen of Ohio State University built the first residential open loop version in his home in 1948.[20] The technology became popular in Sweden as a result of the 1973 oil crisis, and has been growing slowly in worldwide acceptance since then. The 1979 development of polybutylene pipe greatly augmented the heat pump’s economic viability.[18]

In 1960, Pacific Gas and Electric began operation of the first successful geothermal electric power plant in the United States at The Geysers in California.[21] The original turbine lasted for more than 30 years and produced 11 MW net power.[22]

The binary cycle power plant was first demonstrated in 1967 in the USSR and later introduced to the US in 1981.[21] This technology allows the generation of electricity from much lower temperature resources than previously. In 2006, a binary cycle plant in Chena Hot Springs, Alaska, came on-line, producing electricity from a record low fluid temperature of 57 °C (135 °F).[23]

Electricity[edit]

Main article: Geothermal electricity

The International Geothermal Association (IGA) has reported that 10,715 megawatts (MW) of geothermal power in 24 countries is online, which was expected to generate 67,246 GWh of electricity in 2010.[24] This represents a 20% increase in online capacity since 2005. IGA projects growth to 18,500 MW by 2015, due to the projects presently under consideration, often in areas previously assumed to have little exploitable resource.[24]

In 2010, the United States led the world in geothermal electricity production with 3,086 MW of installed capacity from 77 power plants.[25] The largest group of geothermal power plants in the world is located at The Geysers, a geothermal field in California.[26] The Philippines is the second highest producer, with 1,904 MW of capacity online. Geothermal power makes up approximately 27% of Philippine electricity generation.[25]

Installed geothermal electric capacity

Country Capacity (MW)

2007[14] Capacity (MW)

2010[27] Percentage of national

electricity production Percentage of global

geothermal production

United States 2687 3086 0.3 29

Philippines 1969.7 1904 27 18

Indonesia 992 1197 3.7 11

Mexico 953 958 3 9

Italy 810.5 843 1.5 8

New Zealand 471.6 628 10 6

Iceland 421.2 575 30 5

Japan 535.2 536 0.1 5

Iran 250 250

El Salvador 204.2 204 25

Kenya 128.8 167 11.2

Costa Rica 162.5 166 14

Nicaragua 87.4 88 10

Russia 79 82

Turkey 38 82

Papua-New Guinea 56 56

Guatemala 53 52

Portugal 23 29

China 27.8 24

France 14.7 16

Ethiopia 7.3 7.3

Germany 8.4 6.6

Austria 1.1 1.4

Australia 0.2 1.1

Thailand 0.3 0.3

TOTAL 9,981.9 10,959.7

Geothermal electric plants were traditionally built exclusively on the edges of tectonic plates where high temperature geothermal resources are available near the surface. The development of binary cycle power plants and improvements in drilling and extraction technology enable enhanced geothermal systems over a much greater geographical range.[28] Demonstration projects are operational in Landau-Pfalz, Germany, and Soultz-sous-Forêts, France, while an earlier effort in Basel, Switzerland was shut down after it triggered earthquakes. Other demonstration projects are under construction in Australia, the United Kingdom, and the United States of America.[29]

The thermal efficiency of geothermal electric plants is low, around 10–23%, because geothermal fluids do not reach the high temperatures of steam from boilers. The laws of thermodynamics limits the efficiency of heat engines in extracting useful energy. Exhaust heat is wasted, unless it can be used directly and locally, for example in greenhouses, timber mills, and district heating. System efficiency does not materially affect operational costs as it would for plants that use fuel, but it does affect return on the capital used to build the plant. In order to produce more energy than the pumps consume, electricity generation requires relatively hot fields and specialized heat cycles.[citation needed] Because geothermal power does not rely on variable sources of energy, unlike, for example, wind or solar, its capacity factor can be quite large – up to 96% has been demonstrated.[30] The global average was 73% in 2005.

Types[edit]

Geothermal energy comes in either vapor-dominated or liquid-dominated forms. Larderello and The Geysers are vapor-dominated. Vapor-dominated sites offer temperatures from 240-300 C that produce superheated steam.

Liquid-dominated plants[edit]

Liquid-dominated reservoirs (LDRs) are more common with temperatures greater than 200 °C (392 °F) and are found near young volcanoes surrounding the Pacific Ocean and in rift zones and hot spots. Flash plants are the most common way to generate electricity from these sources. Pumps are generally not required, powered instead when the water turns to steam. Most wells generate 2-10MWe. Steam is separated from liquid via cyclone separators, while the liquid is returned to the reservoir for reheating/reuse. As of 2013, the largest liquid system is Cerro Prieto in Mexico, which generates 750 MWe from temperatures reaching 350 °C (662 °F). The Salton Sea field in Southern California offers the potential of generating 2000 MWe.[16]

Lower temperature LDRs (120-200 C) require pumping. They are common in extensional terrains, where heating takes place via deep circulation along faults, such as in the Western US and Turkey. Water passes through a heat exchanger in a Rankine cycle binary plant. The water vaporizes an organic working fluid that drives a turbine. These binary plants originated in the Soviet Union in the late 1960s and predominate in new US plants. Binary plants have no emissions.[16][31]

Thermal energy[edit]

Main articles: Geothermal heating and geothermal heat pump

Lower temperature sources produce the energy equivalent of 100M BBL per year. Sources with temperatures from 30-150 C are used without conversion to electricity for as district heating, greenhouses, fisheries, mineral recovery, industrial process heating and bathing in 75 countries. Heat pumps extract energy from shallow sources at 10-20 C in 43 countries for use in space heating and cooling. Home heating is the fastest-growing means of exploiting geothermal energy, with global annual growth rate of 30% in 2005[32] and 20% in 2012.[16][31]

Approximately 270 petajoules (PJ) of geothermal heating was used in 2004. More than half went for space heating, and another third for heated pools. The remainder supported industrial and agricultural applications. Global installed capacity was 28 GW, but capacity factors tend to be low (30% on average) since heat is mostly needed in winter. Some 88 PJ for space heating was extracted by an estimated 1.3 million geothermal heat pumps with a total capacity of 15 GW.[6]

Heat for these purposes may also be extracted from co-generation at a geothermal electrical plant.

Heating is cost-effective at many more sites than electricity generation. At natural hot springs or geysers, water can be piped directly into radiators. In hot, dry ground, earth tubes or downhole heat exchangers can collect the heat. However, even in areas where the ground is colder than room temperature, heat can often be extracted with a geothermal heat pump more cost-effectively and cleanly than by conventional furnaces.[33] These devices draw on much shallower and colder resources than traditional geothermal techniques. They frequently combine functions, including air conditioning, seasonal thermal energy storage, solar energy collection, and electric heating. Heat pumps can be used for space heating essentially anywhere.

Iceland is the world leader in direct applications. Some 92.5% of its homes are heated with geothermal energy, saving Iceland over $100 million annually in avoided oil imports. Reykjavík, Iceland has the world's biggest district heating system. Once known as the most polluted city in the world, it is now one of the cleanest.[34]

Enhanced geothermal[edit]

Main article: Enhanced geothermal system

Enhanced geothermal systems (EGS) actively inject water into wells to be heated and pumped back out. The water is injected under high pressure to expand existing rock fissures to enable the water to freely flow in and out. The technique was adapted from oil and gas extraction techniques. However, the geologic formations are deeper and no toxic chemicals are used, reducing the possibility of environmental damage. Drillers can employ directional drilling to expand the size of the reservoir.[16]

Small-scale EGS have been installed in the Rhine Graben at Soultz-sou-Forects in France and at Landau and Insheim in Germany.[16]

Economics[edit]

Geothermal power requires no fuel (except for pumps), and is therefore immune to fuel cost fluctuations. However, capital costs are significant. Drilling accounts for over half the costs, and exploration of deep resources entails significant risks. A typical well doublet (extraction and injection wells) in Nevada can support 4.5 megawatts (MW) and costs about $10 million to drill, with a 20% failure rate.[35]

A power plant at The Geysers

In total, electrical plant construction and well drilling cost about €2–5 million per MW of electrical capacity, while the break–even price is 0.04–0.10 € per kW·h.[14] Enhanced geothermal systems tend to be on the high side of these ranges, with capital costs above $4 million per MW and break–even above $0.054 per kW·h in 2007.[36] Direct heating applications can use much shallower wells with lower temperatures, so smaller systems with lower costs and risks are feasible. Residential geothermal heat pumps with a capacity of 10 kilowatt (kW) are routinely installed for around $1–3,000 per kilowatt. District heating systems may benefit from economies of scale if demand is geographically dense, as in cities and greenhouses, but otherwise piping installation dominates capital costs. The capital cost of one such district heating system in Bavaria was estimated at somewhat over 1 million € per MW.[37] Direct systems of any size are much simpler than electric generators and have lower maintenance costs per kW·h, but they must consume electricity to run pumps and compressors. Some governments subsidize geothermal projects.

Geothermal power is highly scalable: from a rural village to an entire city.[38]

The most developed geothermal field in the United States is The Geysers in Northern California.[39]

Geothermal projects have several stages of development. Each phase has associated risks. At the early stages of reconnaissance and geophysical surveys, many project are cancelled, making that phase unsuitable for traditional lending. Projects moving forward from the identification, exploration and exploratory drilling often trade equity for financing.[40]

Resources[edit]

Enhanced geothermal system 1:Reservoir 2:Pump house 3:Heat exchanger 4:Turbine hall 5:Production well 6:Injection well 7:Hot water to district heating 8:Porous sediments 9:Observation well 10:Crystalline bedrock

The Earth's internal thermal energy flows to the surface by conduction at a rate of 44.2 terawatts (TW),[41] and is replenished by radioactive decay of minerals at a rate of 30 TW.[42] These power rates are more than double humanity’s current energy consumption from all primary sources, but most of this energy flow is not recoverable. In addition to the internal heat flows, the top layer of the surface to a depth of 10 meters (33 ft) is heated by solar energy during the summer, and releases that energy and cools during the winter.

Outside of the seasonal variations, the geothermal gradient of temperatures through the crust is 25–30 °C (77–86 °F) per kilometer of depth in most of the world. The conductive heat flux averages 0.1 MW/km2. These values are much higher near tectonic plate boundaries where the crust is thinner. They may be further augmented by fluid circulation, either through magma conduits, hot springs, hydrothermal circulation or a combination of these.

A geothermal heat pump can extract enough heat from shallow ground anywhere in the world to provide home heating, but industrial applications need the higher temperatures of deep resources.[12] The thermal efficiency and profitability of electricity generation is particularly sensitive to temperature. The more demanding applications receive the greatest benefit from a high natural heat flux, ideally from using a hot spring. The next best option is to drill a well into a hot aquifer. If no adequate aquifer is available, an artificial one may be built by injecting water to hydraulically fracture the bedrock. This last approach is called hot dry rock geothermal energy in Europe, or enhanced geothermal systems in North America. Much greater potential may be available from this approach than from conventional tapping of natural aquifers.[28]

Estimates of the potential for electricity generation from geothermal energy vary sixfold, from .035to2TW depending on the scale of investments.[6] Upper estimates of geothermal resources assume enhanced geothermal wells as deep as 10 kilometres (6 mi), whereas existing geothermal wells are rarely more than 3 kilometres (2 mi) deep.[6] Wells of this depth are now common in the petroleum industry. The deepest research well in the world, the Kola superdeep borehole, is 12 kilometres (7 mi) deep.[43] This record has recently been imitated by commercial oil wells, such as Exxon's Z-12 well in the Chayvo field, Sakhalin.[44]

Production[edit]

According to the Geothermal Energy Association (GEA) installed geothermal capacity in the United States grew by 5%, or 147.05 MW, since the last annual survey in March 2012. This increase came from seven geothermal projects that began production in 2012. GEA also revised its 2011 estimate of installed capacity upward by 128 MW, bringing current installed U.S. geothermal capacity to 3,386 MW.[45]

Renewability and sustainability[edit]

Geothermal power is considered to be renewable because any projected heat extraction is small compared to the Earth's heat content. The Earth has an internal heat content of 1031 joules (3·1015 TW·hr).[6] About 20% of this is residual heat from planetary accretion, and the remainder is attributed to higher radioactive decay rates that existed in the past.[2] Natural heat flows are not in equilibrium, and the planet is slowly cooling down on geologic timescales. Human extraction taps a minute fraction of the natural outflow, often without accelerating it.

Geothermal power is also considered to be sustainable thanks to its power to sustain the Earth’s intricate ecosystems. By using geothermal sources of energy present generations of humans will not endanger the capability of future generations to use their own resources to the same amount that those energy sources are presently used. Further, due to its low emissions geothermal energy is considered to have excellent potential for mitigation of global warming.[46]

Even though geothermal power is globally sustainable, extraction must still be monitored to avoid local depletion.[42] Over the course of decades, individual wells draw down local temperatures and water levels until a new equilibrium is reached with natural flows. The three oldest sites, at Larderello, Wairakei, and the Geysers have experienced reduced output because of local depletion. Heat and water, in uncertain proportions, were extracted faster than they were replenished. If production is reduced and water is reinjected, these wells could theoretically recover their full potential. Such mitigation strategies have already been implemented at some sites. The long-term sustainability of geothermal energy has been demonstrated at the Lardarello field in Italy since 1913, at the Wairakei field in New Zealand since 1958,[47] and at The Geysers field in California since 1960.[48]

Electricity Generation at Poihipi, New Zealand.

Electricity Generation at Ohaaki, New Zealand.

Electricity Generation at Wairakei, New Zealand.

Falling electricity production may be boosted through drilling additional supply boreholes, as at Poihipi and Ohaaki. The Wairakei power station has been running much longer, with its first unit commissioned in November 1958, and it attained its peak generation of 173MW in 1965, but already the supply of high-pressure steam was faltering, in 1982 being derated to intermediate pressure and the station managing 157MW. Around the start of the 21st century it was managing about 150MW, then in 2005 two 8MW isopentane systems were added, boosting the station's output by about 14MW. Detailed data are unavailable, being lost due to re-organisations. One such re-organisation in 1996 causes the absence of early data for Poihipi (started 1996), and the gap in 1996/7 for Wairakei and Ohaaki; half-hourly data for Ohaaki's first few months of operation are also missing, as well as for most of Wairakei's history.

Environmental effects[edit]

Geothermal power station in the Philippines

Krafla Geothermal Station in northeast Iceland

Fluids drawn from the deep earth carry a mixture of gases, notably carbon dioxide (CO

2), hydrogen sulfide (H

2S), methane (CH

4) and ammonia (NH

3). These pollutants contribute to global warming, acid rain, and noxious smells if released. Existing geothermal electric plants emit an average of 122 kilograms (269 lb) of CO

2 per megawatt-hour (MW·h) of electricity, a small fraction of the emission intensity of conventional fossil fuel plants.[49] Plants that experience high levels of acids and volatile chemicals are usually equipped with emission-control systems to reduce the exhaust.

In addition to dissolved gases, hot water from geothermal sources may hold in solution trace amounts of toxic elements such as mercury, arsenic, boron, and antimony.[50] These chemicals precipitate as the water cools, and can cause environmental damage if released. The modern practice of injecting cooled geothermal fluids back into the Earth to stimulate production has the side benefit of reducing this environmental risk.

Direct geothermal heating systems contain pumps and compressors, which may consume energy from a polluting source. This parasitic load is normally a fraction of the heat output, so it is always less polluting than electric heating. However, if the electricity is produced by burning fossil fuels, then the net emissions of geothermal heating may be comparable to directly burning the fuel for heat. For example, a geothermal heat pump powered by electricity from a combined cycle natural gas plant would produce about as much pollution as a natural gas condensing furnace of the same size.[33] Therefore the environmental value of direct geothermal heating applications is highly dependent on the emissions intensity of the neighboring electric grid.

Plant construction can adversely affect land stability. Subsidence has occurred in the Wairakei field in New Zealand.[12] In Staufen im Breisgau, Germany, tectonic uplift occurred instead, due to a previously isolated anhydrite layer coming in contact with water and turning into gypsum, doubling its volume.[51][52][53] Enhanced geothermal systems can trigger earthquakes as part of hydraulic fracturing. The project in Basel, Switzerland was suspended because more than 10,000 seismic events measuring up to 3.4 on the Richter Scale occurred over the first 6 days of water injection.[54]

Geothermal has minimal land and freshwater requirements. Geothermal plants use 3.5 square kilometres (1.4 sq mi) per gigawatt of electrical production (not capacity) versus 32 square kilometres (12 sq mi) and 12 square kilometres (4.6 sq mi) for coal facilities and wind farms respectively.[12] They use 20 litres (5.3 US gal) of freshwater per MW·h versus over 1,000 litres (260 US gal) per MW·h for nuclear, coal, or oil.[12]

Legal frameworks[edit]

Some of the legal issues raised by geothermal energy resources include questions of ownership and allocation of the resource, the grant of exploration permits, exploitation rights, royalties, and the extent to which geothermal energy issues have been recognised in existing planning and environmental laws. Other questions concern overlap between geothermal and mineral or petroleum tenements. Broader issues concern the extent to which the legal framework for encouragement of renewable energy assists in encouraging geothermal industry innovation and development.

Solar energy

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For the academic journal, see Solar Energy (journal).

Part of the 354 MW SEGS solar complex in northern San Bernardino County, California, USA

Solar energy is radiant light and heat from the sun harnessed using a range of ever-evolving technologies such as solar heating, solar photovoltaics, solar thermal electricity, solar architecture and artificial photosynthesis.[1][2]

Solar technologies are broadly characterized as either passive solar or active solar depending on the way they capture, convert and distribute solar energy. Active solar techniques include the use of photovoltaic panels and solar thermal collectors to harness the energy. Passive solar techniques include orienting a building to the Sun, selecting materials with favorable thermal mass or light dispersing properties, and designing spaces that naturally circulate air.

In 2011, the International Energy Agency said that "the development of affordable, inexhaustible and clean solar energy technologies will have huge longer-term benefits. It will increase countries’ energy security through reliance on an indigenous, inexhaustible and mostly import-independent resource, enhance sustainability, reduce pollution, lower the costs of mitigating climate change, and keep fossil fuel prices lower than otherwise. These advantages are global. Hence the additional costs of the incentives for early deployment should be considered learning investments; they must be wisely spent and need to be widely shared".[1]

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Contents [hide]

1 Energy from the Sun

2 Early commercial adaption

3 Applications of solar technology

3.1 Architecture and urban planning

3.2 Agriculture and horticulture

3.3 Transport and reconnaissance

3.4 Solar thermal

3.4.1 Water heating

3.4.2 Heating, cooling and ventilation

3.4.3 Water treatment

3.4.4 Process heat

3.4.5 Cooking

3.5 Electricity production

3.5.1 Concentrated solar power

3.5.2 Photovoltaics

3.5.3 Others

3.6 Fuel production

4 Energy storage methods

5 Development, deployment and economics

6 ISO Standards

7 See also

8 Notes

9 References

10 External links

Energy from the Sun

Main articles: Insolation and Solar radiation

About half the incoming solar energy reaches the Earth's surface.

The Earth receives 174 petawatts (PW) of incoming solar radiation (insolation) at the upper atmosphere.[3] Approximately 30% is reflected back to space while the rest is absorbed by clouds, oceans and land masses. The spectrum of solar light at the Earth's surface is mostly spread across the visible and near-infrared ranges with a small part in the near-ultraviolet.[4]

Earth's land surface, oceans and atmosphere absorb solar radiation, and this raises their temperature. Warm air containing evaporated water from the oceans rises, causing atmospheric circulation or convection. When the air reaches a high altitude, where the temperature is low, water vapor condenses into clouds, which rain onto the Earth's surface, completing the water cycle. The latent heat of water condensation amplifies convection, producing atmospheric phenomena such as wind, cyclones and anti-cyclones.[5] Sunlight absorbed by the oceans and land masses keeps the surface at an average temperature of 14 °C.[6] By photosynthesis green plants convert solar energy into chemical energy, which produces food, wood and the biomass from which fossil fuels are derived.[7]

Yearly Solar fluxes & Human Energy Consumption

Solar 3,850,000 EJ [8]

Wind 2,250 EJ [9]

Biomass potential ~200 EJ [10]

Primary energy use (2010) 539 EJ [11]

Electricity (2010) ~67 EJ [12]

1 Exajoule (EJ) is 1018 Joules or 278 billion kilowatt-hours (kW·h).

The total solar energy absorbed by Earth's atmosphere, oceans and land masses is approximately 3,850,000 exajoules (EJ) per year.[8] In 2002, this was more energy in one hour than the world used in one year.[13][14] Photosynthesis captures approximately 3,000 EJ per year in biomass.[15] The technical potential available from biomass is from 100–300 EJ/year.[10] The amount of solar energy reaching the surface of the planet is so vast that in one year it is about twice as much as will ever be obtained from all of the Earth's non-renewable resources of coal, oil, natural gas, and mined uranium combined,[16]

Solar energy can be harnessed at different levels around the world, mostly depending on distance from the equator.[17]

Early commercial adaption

A 1917 patent drawing for Shuman's parabolic trough solar energy system

In 1897, Frank Shuman, a U.S. inventor, engineer and solar energy pioneer built a small demonstration solar engine that worked by reflecting solar energy onto square boxes filled with ether, which has a lower boiling point than water, and were fitted internally with black pipes which in turn powered a steam engine. In 1908 Shuman formed the Sun Power Company with the intent of building larger solar power plants. He, along with his technical advisor A.S.E. Ackermann and British physicist Sir Charles Vernon Boys,[18] developed an improved system using mirrors to reflect solar energy upon collector boxes, increasing heating capacity to the extent that water could now be used instead of ether. Shuman then constructed a full-scale steam engine powered by low-pressure water, enabling him to patent the entire solar engine system by 1912.

Shuman built the world’s first solar thermal power station in Maadi, Egypt between 1912 and 1913. Shuman’s plant used parabolic troughs to power a 45-52 kilowatt (60-70 H.P.) engine that pumped more than 22,000 litres of water per minute from the Nile River to adjacent cotton fields. Although the outbreak of World War I and the discovery of cheap oil in the 1930s discouraged the advancement of solar energy, Shuman’s vision and basic design were resurrected in the 1970s with a new wave of interest in solar thermal energy.[19] In 1916 Shuman was quoted in the media advocating solar energy's utilization, saying:

We have proved the commercial profit of sun power in the tropics and have more particularly proved that after our stores of oil and coal are exhausted the human race can receive unlimited power from the rays of the sun.

—Frank Shuman, New York Times, July 2, 1916[20]

Applications of solar technology

Average insolation showing land area (small black dots) required to replace the world primary energy supply with solar electricity (18 TW is 568 Exajoule, EJ, per year). Insolation for most people is from 150 to 300 W/m2 or 3.5 to 7.0 kWh/m2/day.

Solar energy refers primarily to the use of solar radiation for practical ends. However, all renewable energies, other than geothermal and tidal, derive their energy from the sun.

Solar technologies are broadly characterized as either passive or active depending on the way they capture, convert and distribute sunlight. Active solar techniques use photovoltaic panels, pumps, and fans to convert sunlight into useful outputs. Passive solar techniques include selecting materials with favorable thermal properties, designing spaces that naturally circulate air, and referencing the position of a building to the Sun. Active solar technologies increase the supply of energy and are considered supply side technologies, while passive solar technologies reduce the need for alternate resources and are generally considered demand side technologies.[21]

Architecture and urban planning

Main articles: Passive solar building design and Urban heat island

Darmstadt University of Technology in Germany won the 2007 Solar Decathlon in Washington, D.C. with this passive house designed specifically for the humid and hot subtropical climate.[22]

Sunlight has influenced building design since the beginning of architectural history.[23] Advanced solar architecture and urban planning methods were first employed by the Greeks and Chinese, who oriented their buildings toward the south to provide light and warmth.[24]

The common features of passive solar architecture are orientation relative to the Sun, compact proportion (a low surface area to volume ratio), selective shading (overhangs) and thermal mass.[23] When these features are tailored to the local climate and environment they can produce well-lit spaces that stay in a comfortable temperature range. Socrates' Megaron House is a classic example of passive solar design.[23] The most recent approaches to solar design use computer modeling tying together solar lighting, heating and ventilation systems in an integrated solar design package.[25] Active solar equipment such as pumps, fans and switchable windows can complement passive design and improve system performance.

Urban heat islands (UHI) are metropolitan areas with higher temperatures than that of the surrounding environment. The higher temperatures are a result of increased absorption of the Solar light by urban materials such as asphalt and concrete, which have lower albedos and higher heat capacities than those in the natural environment. A straightforward method of counteracting the UHI effect is to paint buildings and roads white and plant trees. Using these methods, a hypothetical "cool communities" program in Los Angeles has projected that urban temperatures could be reduced by approximately 3 °C at an estimated cost of US$1 billion, giving estimated total annual benefits of US$530 million from reduced air-conditioning costs and healthcare savings.[26]

Agriculture and horticulture

Greenhouses like these in the Westland municipality of the Netherlands grow vegetables, fruits and flowers.

Agriculture and horticulture seek to optimize the capture of solar energy in order to optimize the productivity of plants. Techniques such as timed planting cycles, tailored row orientation, staggered heights between rows and the mixing of plant varieties can improve crop yields.[27][28] While sunlight is generally considered a plentiful resource, the exceptions highlight the importance of solar energy to agriculture. During the short growing seasons of the Little Ice Age, French and English farmers employed fruit walls to maximize the collection of solar energy. These walls acted as thermal masses and accelerated ripening by keeping plants warm. Early fruit walls were built perpendicular to the ground and facing south, but over time, sloping walls were developed to make better use of sunlight. In 1699, Nicolas Fatio de Duillier even suggested using a tracking mechanism which could pivot to follow the Sun.[29] Applications of solar energy in agriculture aside from growing crops include pumping water, drying crops, brooding chicks and drying chicken manure.[30][31] More recently the technology has been embraced by vinters, who use the energy generated by solar panels to power grape presses.[32]

Greenhouses convert solar light to heat, enabling year-round production and the growth (in enclosed environments) of specialty crops and other plants not naturally suited to the local climate. Primitive greenhouses were first used during Roman times to produce cucumbers year-round for the Roman emperor Tiberius.[33] The first modern greenhouses were built in Europe in the 16th century to keep exotic plants brought back from explorations abroad.[34] Greenhouses remain an important part of horticulture today, and plastic transparent materials have also been used to similar effect in polytunnels and row covers.

Transport and reconnaissance

Main articles: Solar vehicle, Solar-charged vehicle, Electric boat and Solar balloon

Australia hosts the World Solar Challenge where solar cars like the Nuna3 race through a 3,021 km (1,877 mi) course from Darwin to Adelaide.

Development of a solar-powered car has been an engineering goal since the 1980s. The World Solar Challenge is a biannual solar-powered car race, where teams from universities and enterprises compete over 3,021 kilometres (1,877 mi) across central Australia from Darwin to Adelaide. In 1987, when it was founded, the winner's average speed was 67 kilometres per hour (42 mph) and by 2007 the winner's average speed had improved to 90.87 kilometres per hour (56.46 mph).[35] The North American Solar Challenge and the planned South African Solar Challenge are comparable competitions that reflect an international interest in the engineering and development of solar powered vehicles.[36][37]

Some vehicles use solar panels for auxiliary power, such as for air conditioning, to keep the interior cool, thus reducing fuel consumption.[38][39]

In 1975, the first practical solar boat was constructed in England.[40] By 1995, passenger boats incorporating PV panels began appearing and are now used extensively.[41] In 1996, Kenichi Horie made the first solar powered crossing of the Pacific Ocean, and the sun21 catamaran made the first solar powered crossing of the Atlantic Ocean in the winter of 2006–2007.[42] There are plans to circumnavigate the globe in 2010.[43]

Helios UAV in solar powered flight.

In 1974, the unmanned AstroFlight Sunrise plane made the first solar flight. On 29 April 1979, the Solar Riser made the first flight in a solar-powered, fully controlled, man carrying flying machine, reaching an altitude of 40 feet (12 m). In 1980, the Gossamer Penguin made the first piloted flights powered solely by photovoltaics. This was quickly followed by the Solar Challenger which crossed the English Channel in July 1981. In 1990 Eric Scott Raymond in 21 hops flew from California to North Carolina using solar power.[44] Developments then turned back to unmanned aerial vehicles (UAV) with the Pathfinder (1997) and subsequent designs, culminating in the Helios which set the altitude record for a non-rocket-propelled aircraft at 29,524 metres (96,864 ft) in 2001.[45] The Zephyr, developed by BAE Systems, is the latest in a line of record-breaking solar aircraft, making a 54-hour flight in 2007, and month-long flights are envisioned by 2010.[46]

A solar balloon is a black balloon that is filled with ordinary air. As sunlight shines on the balloon, the air inside is heated and expands causing an upward buoyancy force, much like an artificially heated hot air balloon. Some solar balloons are large enough for human flight, but usage is generally limited to the toy market as the surface-area to payload-weight ratio is relatively high.[47]

Solar thermal

Main article: Solar thermal energy

Solar thermal technologies can be used for water heating, space heating, space cooling and process heat generation.[48]

Water heating

Main articles: Solar hot water and Solar combisystem

Solar water heaters facing the Sun to maximize gain.

Solar hot water systems use sunlight to heat water. In low geographical latitudes (below 40 degrees) from 60 to 70% of the domestic hot water use with temperatures up to 60 °C can be provided by solar heating systems.[49] The most common types of solar water heaters are evacuated tube collectors (44%) and glazed flat plate collectors (34%) generally used for domestic hot water; and unglazed plastic collectors (21%) used mainly to heat swimming pools.[50]

As of 2007, the total installed capacity of solar hot water systems is approximately 154 GW.[51] China is the world leader in their deployment with 70 GW installed as of 2006 and a long term goal of 210 GW by 2020.[52] Israel and Cyprus are the per capita leaders in the use of solar hot water systems with over 90% of homes using them.[53] In the United States, Canada and Australia heating swimming pools is the dominant application of solar hot water with an installed capacity of 18 GW as of 2005.[21]

Heating, cooling and ventilation

Main articles: Solar heating, Thermal mass, Solar chimney and Solar air conditioning

Solar House #1 of Massachusetts Institute of Technology in the United States, built in 1939, used Seasonal thermal energy storage for year-round heating.

In the United States, heating, ventilation and air conditioning (HVAC) systems account for 30% (4.65 EJ) of the energy used in commercial buildings and nearly 50% (10.1 EJ) of the energy used in residential buildings.[54][55] Solar heating, cooling and ventilation technologies can be used to offset a portion of this energy.

Thermal mass is any material that can be used to store heat—heat from the Sun in the case of solar energy. Common thermal mass materials include stone, cement and water. Historically they have been used in arid climates or warm temperate regions to keep buildings cool by absorbing solar energy during the day and radiating stored heat to the cooler atmosphere at night. However they can be used in cold temperate areas to maintain warmth as well. The size and placement of thermal mass depend on several factors such as climate, daylighting and shading conditions. When properly incorporated, thermal mass maintains space temperatures in a comfortable range and reduces the need for auxiliary heating and cooling equipment.[56]

A solar chimney (or thermal chimney, in this context) is a passive solar ventilation system composed of a vertical shaft connecting the interior and exterior of a building. As the chimney warms, the air inside is heated causing an updraft that pulls air through the building. Performance can be improved by using glazing and thermal mass materials[57] in a way that mimics greenhouses.

Deciduous trees and plants have been promoted as a means of controlling solar heating and cooling. When planted on the southern side of a building in the northern hemisphere or the northern side in the southern hemisphere, their leaves provide shade during the summer, while the bare limbs allow light to pass during the winter.[58] Since bare, leafless trees shade 1/3 to 1/2 of incident solar radiation, there is a balance between the benefits of summer shading and the corresponding loss of winter heating.[59] In climates with significant heating loads, deciduous trees should not be planted on the Equator facing side of a building because they will interfere with winter solar availability. They can, however, be used on the east and west sides to provide a degree of summer shading without appreciably affecting winter solar gain.[60]

Water treatment

Main articles: Solar still, Solar water disinfection, Solar desalination and Solar Powered Desalination Unit

Solar water disinfection in Indonesia

Small scale solar powered sewerage treatment plant.

Solar distillation can be used to make saline or brackish water potable. The first recorded instance of this was by 16th-century Arab alchemists.[61] A large-scale solar distillation project was first constructed in 1872 in the Chilean mining town of Las Salinas.[62] The plant, which had solar collection area of 4,700 m2, could produce up to 22,700 L per day and operated for 40 years.[62] Individual still designs include single-slope, double-slope (or greenhouse type), vertical, conical, inverted absorber, multi-wick, and multiple effect.[61] These stills can operate in passive, active, or hybrid modes. Double-slope stills are the most economical for decentralized domestic purposes, while active multiple effect units are more suitable for large-scale applications.[61]

Solar water disinfection (SODIS) involves exposing water-filled plastic polyethylene terephthalate (PET) bottles to sunlight for several hours.[63] Exposure times vary depending on weather and climate from a minimum of six hours to two days during fully overcast conditions.[64] It is recommended by the World Health Organization as a viable method for household water treatment and safe storage.[65] Over two million people in developing countries use this method for their daily drinking water.[64]

Solar energy may be used in a water stabilisation pond to treat waste water without chemicals or electricity. A further environmental advantage is that algae grow in such ponds and consume carbon dioxide in photosynthesis, although algae may produce toxic chemicals that make the water unusable.[66][67]

Process heat

Main articles: Solar pond, Salt evaporation pond and Solar furnace

Solar concentrating technologies such as parabolic dish, trough and Scheffler reflectors can provide process heat for commercial and industrial applications. The first commercial system was the Solar Total Energy Project (STEP) in Shenandoah, Georgia, USA where a field of 114 parabolic dishes provided 50% of the process heating, air conditioning and electrical requirements for a clothing factory. This grid-connected cogeneration system provided 400 kW of electricity plus thermal energy in the form of 401 kW steam and 468 kW chilled water, and had a one hour peak load thermal storage.[68]

Evaporation ponds are shallow pools that concentrate dissolved solids through evaporation. The use of evaporation ponds to obtain salt from sea water is one of the oldest applications of solar energy. Modern uses include concentrating brine solutions used in leach mining and removing dissolved solids from waste streams.[69]

Clothes lines, clotheshorses, and clothes racks dry clothes through evaporation by wind and sunlight without consuming electricity or gas. In some states of the United States legislation protects the "right to dry" clothes.[70]

Unglazed transpired collectors (UTC) are perforated sun-facing walls used for preheating ventilation air. UTCs can raise the incoming air temperature up to 22 °C and deliver outlet temperatures of 45–60 °C.[71] The short payback period of transpired collectors (3 to 12 years) makes them a more cost-effective alternative than glazed collection systems.[71] As of 2003, over 80 systems with a combined collector area of 35,000 m2 had been installed worldwide, including an 860 m2 collector in Costa Rica used for drying coffee beans and a 1,300 m2 collector in Coimbatore, India used for drying marigolds.[31]

Cooking

Main article: Solar cooker

The Solar Bowl in Auroville, India, concentrates sunlight on a movable receiver to produce steam for cooking.

Solar cookers use sunlight for cooking, drying and pasteurization. They can be grouped into three broad categories: box cookers, panel cookers and reflector cookers.[72] The simplest solar cooker is the box cooker first built by Horace de Saussure in 1767.[73] A basic box cooker consists of an insulated container with a transparent lid. It can be used effectively with partially overcast skies and will typically reach temperatures of 90–150 °C.[74] Panel cookers use a reflective panel to direct sunlight onto an insulated container and reach temperatures comparable to box cookers. Reflector cookers use various concentrating geometries (dish, trough, Fresnel mirrors) to focus light on a cooking container. These cookers reach temperatures of 315 °C and above but require direct light to function properly and must be repositioned to track the Sun.[75]

Electricity production

View of Ivanpah Solar Electric Generating System from Yates Well Road, San Bernardino County, California. The Clark Mountain Range can be seen in the distance.

Main article: Solar power

Solar power is the conversion of sunlight into electricity, either directly using photovoltaics (PV), or indirectly using concentrated solar power (CSP). CSP systems use lenses or mirrors and tracking systems to focus a large area of sunlight into a small beam. PV converts light into electric current using the photoelectric effect.

Commercial CSP plants were first developed in the 1980s. Since 1985 the eventually 354 MW SEGS CSP installation, in the Mojave Desert of California, is the largest solar power plant in the world. Other large CSP plants include the 150 MW Solnova Solar Power Station and the 100 MW Andasol solar power station, both in Spain. The 250 MW Agua Caliente Solar Project, in the United States, and the 221 MW Charanka Solar Park in India, are the world’s largest photovoltaic plants. Solar projects exceeding 1 GW are being developed, but most of the deployed photovoltaics are in small rooftop arrays of less than 5 kW, which are grid connected using net metering and/or a feed-in tariff.[76]

Concentrated solar power

See also: Cost of electricity by source

Beginning with the surge in coal use which accompanied the Industrial Revolution, energy consumption has steadily transitioned from wood and biomass to fossil fuels. The early development of solar technologies starting in the 1860s was driven by an expectation that coal would soon become scarce. However development of solar technologies stagnated in the early 20th century in the face of the increasing availability, economy, and utility of coal and petroleum.[100]

The 1973 oil embargo and 1979 energy crisis caused a reorganization of energy policies around the world and brought renewed attention to developing solar technologies.[101][102] Deployment strategies focused on incentive programs such as the Federal Photovoltaic Utilization Program in the US and the Sunshine Program in Japan. Other efforts included the formation of research facilities in the US (SERI, now NREL), Japan (NEDO), and Germany (Fraunhofer Institute for Solar Energy Systems ISE).[103]

Commercial solar water heaters began appearing in the United States in the 1890s.[104] These systems saw increasing use until the 1920s but were gradually replaced by cheaper and more reliable heating fuels.[105] As with photovoltaics, solar water heating attracted renewed attention as a result of the oil crises in the 1970s but interest subsided in the 1980s due to falling petroleum prices. Development in the solar water heating sector progressed steadily throughout the 1990s and growth rates have averaged 20% per year since 1999.[51] Although generally underestimated, solar water heating and cooling is by far the most widely deployed solar technology with an estimated capacity of 154 GW as of 2007.[51]

The International Energy Agency has said that solar energy can make considerable contributions to solving some of the most urgent problems the world now faces:[1]

The development of affordable, inexhaustible and clean solar energy technologies will have huge longer-term benefits. It will increase countries’ energy security through reliance on an indigenous, inexhaustible and mostly import-independent resource, enhance sustainability, reduce pollution, lower the costs of mitigating climate change, and keep fossil fuel prices lower than otherwise. These advantages are global. Hence the additional costs of the incentives for early deployment should be considered learning investments; they must be wisely spent and need to be widely shared.[1]

In 2011, the International Energy Agency said that solar energy technologies such as photovoltaic panels, solar water heaters and power stations built with mirrors could provide a third of the world’s energy by 2060 if politicians commit to limiting climate change. The energy from the sun could play a key role in de-carbonizing the global economy alongside improvements in energy efficiency and imposing costs on greenhouse gas emitters. "The strength of solar is the incredible variety and flexibility of applications, from small scale to big scale".[106]

We have proved ... that after our stores of oil and coal are exhausted the human race can receive unlimited power from the rays of the sun.

—Frank Shuman, New York Times, July 2, 1916[107]

ISO Standards

The International Organization for Standardization has established a number of standards relating to solar energy equipment. For example, ISO 9050 relates to glass in building while ISO 10217 relates to the materials used in solar water heaters.

Wind power

From Wikipedia, the free encyclopedia

Burbo Bank Offshore Wind Farm, at the entrance to the River Mersey in northwest England.

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Wind turbines near Vendsyssel, Denmark (2004)

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v t e

Wind power is the conversion of wind energy into a useful form of energy, such as using wind turbines to produce electrical power, windmills for mechanical power, windpumps for water pumping or drainage, or sails to propel ships.

Large wind farms consist of hundreds of individual wind turbines which are connected to the electric power transmission network. For new constructions, onshore wind is an inexpensive source of electricity, competitive with or in many places cheaper than fossil fuel plants.[1][2] Offshore wind is steadier and stronger than on land, and offshore farms have less visual impact, but construction and maintenance costs are considerably higher. Small onshore wind farms can feed some energy into the grid or provide electricity to isolated off-grid locations.[3]

Wind power, as an alternative to fossil fuels, is plentiful, renewable, widely distributed, clean, produces no greenhouse gas emissions during operation and uses little land.[4] The effects on the environment are generally less problematic than those from other power sources. As of 2011, Denmark is generating more than a quarter of its electricity from wind and 83 countries around the world are using wind power to supply the electricity grid.[5] In 2010 wind energy production was over 2.5% of total worldwide electricity usage, and growing rapidly at more than 25% per annum.

Wind power is very consistent from year to year but has significant variation over shorter time scales. As the proportion of windpower in a region increases, a need to upgrade the grid, and a lowered ability to supplant conventional production can occur.[6][7] Power management techniques such as having excess capacity storage, geographically distributed turbines, dispatchable backing sources, storage such as pumped-storage hydroelectricity, exporting and importing power to neighboring areas or reducing demand when wind production is low, can greatly mitigate these problems.[8] In addition, weather forecasting permits the electricity network to be readied for the predictable variations in production that occur.[9][10] Wind power can be considered a topic in applied eolics.[11]

Contents [hide]

1 History

2 Wind farms

2.1 Feeding into grid

2.2 Offshore wind power

3 Wind power capacity and production

3.1 Growth trends

3.2 Capacity factor

3.3 Penetration

3.4 Variability

3.5 Predictability

3.6 Energy storage

3.7 Capacity credit and fuel savings

4 Economics

4.1 Cost trends

4.2 Incentives and community benefits

5 Small-scale wind power

6 Environmental effects

7 Politics

7.1 Central government

7.2 Public opinion

7.3 Community

8 Turbine design

9 Wind energy

10 See also

11 Notes

12 References

13 Further reading

14 External links

History[edit]

Main article: History of wind power

Charles Brush's windmill of 1888, used for generating electricity.

Wind power has been used as long as humans have put sails into the wind. For more than two millennia wind-powered machines have ground grain and pumped water. Wind power was widely available and not confined to the banks of fast-flowing streams, or later, requiring sources of fuel. Wind-powered pumps drained the polders of the Netherlands, and in arid regions such as the American mid-west or the Australian outback, wind pumps provided water for live stock and steam engines.

The first windmill used for the production of electricity was built in Scotland in July 1887 by Prof James Blyth of Anderson's College, Glasgow (the precursor of Strathclyde University).[12] Blyth's 10 m high, cloth-sailed wind turbine was installed in the garden of his holiday cottage at Marykirk in Kincardineshire and was used to charge accumulators developed by the Frenchman Camille Alphonse Faure, to power the lighting in the cottage,[12] thus making it the first house in the world to have its electricity supplied by wind power.[13] Blyth offered the surplus electricity to the people of Marykirk for lighting the main street, however, they turned down the offer as they thought electricity was "the work of the devil."[12] Although he later built a wind turbine to supply emergency power to the local Lunatic Asylum, Infirmary and Dispensary of Montrose the invention never really caught on as the technology was not considered to be economically viable.[12]

Across the Atlantic, in Cleveland, Ohio a larger and heavily engineered machine was designed and constructed in the winter of 1887-1888 by Charles F. Brush,[14] this was built by his engineering company at his home and operated from 1886 until 1900.[15] The Brush wind turbine had a rotor 17 m (56 foot) in diameter and was mounted on an 18 m (60 foot) tower. Although large by today's standards, the machine was only rated at 12 kW. The connected dynamo was used either to charge a bank of batteries or to operate up to 100 incandescent light bulbs, three arc lamps, and various motors in Brush's laboratory.[16]

With the development of electric power, wind power found new applications in lighting buildings remote from centrally-generated power. Throughout the 20th century parallel paths developed small wind plants suitable for farms or residences, and larger utility-scale wind generators that could be connected to electricity grids for remote use of power. Today wind powered generators operate in every size range between tiny plants for battery charging at isolated residences, up to near-gigawatt sized offshore wind farms that provide electricity to national electrical networks.

Wind farms[edit]

Main articles: Wind farm and List of onshore wind farms.

Large onshore wind farms

Wind farm Current

capacity

(MW) Country Notes

Gansu Wind Farm 6,000 China [17][18]

Alta (Oak Creek-Mojave) 1,320 United States [19]

Jaisalmer Wind Park 1,064 India [20]

Shepherds Flat Wind Farm 845 United States [21]

Roscoe Wind Farm 782 United States [22]

Horse Hollow Wind Energy Center 736 United States [23][24]

Capricorn Ridge Wind Farm 662 United States [23][24]

Fântânele-Cogealac Wind Farm 600 Romania [25]

Fowler Ridge Wind Farm 600 United States [26]

Whitelee Wind Farm 539 United Kingdom [27]

A wind farm is a group of wind turbines in the same location used for production of electricity. A large wind farm may consist of several hundred individual wind turbines distributed over an extended area, but the land between the turbines may be used for agricultural or other purposes. A wind farm may also be located offshore.

Almost all large wind turbines have the same design — a horizontal axis wind turbine having an upwind rotor with three blades, attached to a nacelle on top of a tall tubular tower.

In a wind farm, individual turbines are interconnected with a medium voltage (often 34.5 kV), power collection system and communications network. At a substation, this medium-voltage electric current is increased in voltage with a transformer for connection to the high voltage electric power transmission system.[citation needed]

Feeding into grid[edit]

Induction generators, often used for wind power, require reactive power for excitation so substations used in wind-power collection systems include substantial capacitor banks for power factor correction.[28] Different types of wind turbine generators behave differently during transmission grid disturbances, so extensive modelling of the dynamic electromechanical characteristics of a new wind farm is required by transmission system operators to ensure predictable stable behaviour during system faults (see: Low voltage ride through). In particular, induction generators cannot support the system voltage during faults, unlike steam or hydro turbine-driven synchronous generators. Doubly fed machines generally have more desirable properties for grid interconnection.[29][30] Transmission systems operators will supply a wind farm developer with a grid code to specify the requirements for interconnection to the transmission grid. This will include power factor, constancy of frequency and dynamic behavior of the wind farm turbines during a system fault.[31][32]

Offshore wind power[edit]

Main articles: Offshore wind power and List of offshore wind farms

Offshore wind power refers to the construction of wind farms in large bodies of water to generate electricity. These installations can utilise the more frequent and powerful winds that are available in these locations and have less aesthetic impact on the landscape than land based projects. However, the construction and the maintenance costs are considerably higher.[33][34]

Siemens and Vestas are the leading turbine suppliers for offshore wind power. DONG Energy, Vattenfall and E.ON are the leading offshore operators.[35] As of October 2010, 3.16 GW of offshore wind power capacity was operational, mainly in Northern Europe. According to BTM Consult, more than 16 GW of additional capacity will be installed before the end of 2014 and the UK and Germany will become the two leading markets. Offshore wind power capacity is expected to reach a total of 75 GW worldwide by 2020, with significant contributions from China and the US.[35]

At the end of 2012, 1,662 turbines at 55 offshore wind farms in 10 European countries are generating 18 TWh, which can power almost five million households.[36] As of August 2013 the London Array in the United Kingdom is the largest offshore wind farm in the world at 630 MW. This is followed by the Greater Gabbard Wind Farm (504 MW), also in the UK. The Gwynt y Môr wind farm (576 MW) is the largest project currently under construction.[citation needed]

Wind power capacity and production[edit]

Main article: Wind power by country

Worldwide wind generation up to 2010

Worldwide there are now over two hundred thousand wind turbines operating, with a total nameplate capacity of 282,482 MW as of end 2012.[37] The European Union alone passed some 100,000 MW nameplate capacity in September 2012,[38] while the United States surpassed 50,000 MW in August 2012 and China's grid connected capacity passed 50,000 MW the same month.[39][40]

World wind generation capacity more than quadrupled between 2000 and 2006, doubling about every three years. The United States pioneered wind farms and led the world in installed capacity in the 1980s and into the 1990s. In 1997 German installed capacity surpassed the U.S. and led until once again overtaken by the U.S. in 2008. China has been rapidly expanding its wind installations in the late 2000s and passed the U.S. in 2010 to become the world leader.

At the end of 2013, worldwide nameplate capacity of wind-powered generators was 318 gigawatts (GW), growing by 35 GW over the preceding year.[37] According to the World Wind Energy Association, an industry organization, in 2010 wind power generated 430 TWh or about 2.5% of worldwide electricity usage,[41] up from 1.5% in 2008 and 0.1% in 1997.[42] Between 2005 and 2010 the average annual growth in new installations was 27.6%.[43] Wind power market penetration is expected to reach 3.35% by 2013 and 8% by 2018.[43][44]

The actual amount of electricity that wind is able to generate is calculated by multiplying the nameplate capacity by the capacity factor, which varies according to equipment and location. Estimates of the capacity factors for wind installations are in the range of 35% to 44%.[45]

Several countries have already achieved relatively high levels of penetration, such as 28% of stationary (grid) electricity production in Denmark (2011),[46] 19% in Portugal (2011),[47] 16% in Spain (2011),[48] 16% in Ireland (2012)[49] and 8% in Germany (2011).[50] As of 2011, 83 countries around the world were using wind power on a commercial basis.[5]

Europe accounted for 48% of the world total wind power generation capacity in 2009. In 2010, Spain became Europe's leading producer of wind energy, achieving 42,976 GWh. Germany held the top spot in Europe in terms of installed capacity, with a total of 27,215 MW as of 31 December 2010.[51]

Top 10 countries

by nameplate windpower capacity

(2013 year-end)[37]

Country New 2013

capacity (MW) Windpower total capacity

(MW) % world total

China 16,088 91,412 28.7

United States 1,084 61,091 19.2

Germany 3,238 34,250 10.8

Spain 175 22,959 7.2

India 1,729 20,150 6.3

UK 1,883 10,531 3.3

Italy 444 8,552 2.7

France 631 8,254 2.6

Canada 1,599 7,803 2.5

Denmark 657 4,772 1.5

(rest of world) 7,761 48,332 15.2

World total 35,289 MW 318,105 MW 100%

Top 10 countries

by windpower electricity production

(2012 totals)[52]

Country Windpower production

(TWh) % world total

United States 140.9 26.4

China 118.1 22.1

Spain 49.1 9.2

Germany 46.0 8.6

India 30.0 5.6

UK 19.6 3.7

France 14.9 2.8

Italy 13.4 2.5

Canada 11.8 2.2

Denmark 10.3 1.9

(rest of world) 80.2 15.0

World total 534.3 TWh 100%

Growth trends[edit]

Worldwide installed capacity 1997–2020 [MW], developments and prognosis. Data source: WWEA[53]

Worldwide installed wind power capacity forecast (Source: Global Wind Energy Council)[54][55]

In 2010, more than half of all new wind power was added outside of the traditional markets in Europe and North America. This was largely from new construction in China, which accounted for nearly half the new wind installations (16.5 GW).[56]

Global Wind Energy Council (GWEC) figures show that 2007 recorded an increase of installed capacity of 20 GW, taking the total installed wind energy capacity to 94 GW, up from 74 GW in 2006. Despite constraints facing supply chains for wind turbines, the annual market for wind continued to increase at an estimated rate of 37%, following 32% growth in 2006. In terms of economic value, the wind energy sector has become one of the important players in the energy markets, with the total value of new generating equipment installed in 2007 reaching €25 billion, or US$36 billion.[57]

Although the wind power industry was affected by the global financial crisis in 2009 and 2010, a BTM Consult five-year forecast up to 2013 projects substantial growth. Over the past five years the average growth in new installations has been 27.6% each year. In the forecast to 2013 the expected average annual growth rate is 15.7%.[43][44] More than 200 GW of new wind power capacity could come on line before the end of 2014. Wind power market penetration is expected to reach 3.35% by 2013 and 8% by 2018.[43][44]

Capacity factor[edit]

Since wind speed is not constant, a wind farm's annual energy production is never as much as the sum of the generator nameplate ratings multiplied by the total hours in a year. The ratio of actual productivity in a year to this theoretical maximum is called the capacity factor. Typical capacity factors are 15–50%; values at the upper end of the range are achieved in favourable sites and are due to wind turbine design improvements.[58][59][nb 1]

Online data is available for some locations, and the capacity factor can be calculated from the yearly output.[60][61] For example, the German nation-wide average wind power capacity factor over all of 2012 was just under 17.5% (45867 GW·h/yr / (29.9 GW × 24 × 366) = 0.1746),[62] and the capacity factor for Scottish wind farms averaged 24% between 2008 and 2010.[63]

Unlike fueled generating plants, the capacity factor is affected by several parameters, including the variability of the wind at the site and the size of the generator relative to the turbine's swept area. A small generator would be cheaper and achieve a higher capacity factor but would produce less electricity (and thus less profit) in high winds. Conversely, a large generator would cost more but generate little extra power and, depending on the type, may stall out at low wind speed. Thus an optimum capacity factor of around 40–50% would be aimed for.[59][64]

In a 2008 study released by the U.S. Department of Energy's Office of Energy Efficiency and Renewable Energy, the capacity factor achieved by the U.S. wind turbine fleet is shown to be increasing as the technology improves. The capacity factor achieved by new wind turbines in 2010 reached almost 40%.[65][66]

Penetration[edit]

A panoramic view of the United Kingdom's Whitelee Wind Farm with Lochgoin Reservoir in the foreground.

Wind energy penetration refers to the fraction of energy produced by wind compared with the total available generation capacity. There is no generally accepted maximum level of wind penetration. The limit for a particular grid will depend on the existing generating plants, pricing mechanisms, capacity for energy storage, demand management and other factors. An interconnected electricity grid will already include reserve generating and transmission capacity to allow for equipment failures. This reserve capacity can also serve to compensate for the varying power generation produced by wind plants. Studies have indicated that 20% of the total annual electrical energy consumption may be incorporated with minimal difficulty.[67] These studies have been for locations with geographically dispersed wind farms, some degree of dispatchable energy or hydropower with storage capacity, demand management, and interconnected to a large grid area enabling the export of electricity when needed. Beyond the 20% level, there are few technical limits, but the economic implications become more significant. Electrical utilities continue to study the effects of large scale penetration of wind generation on system stability and economics.[68][69][70][71]

A wind energy penetration figure can be specified for different durations of time. On an annual basis, as of 2011, few grid systems have penetration levels above 5%: Denmark – 29%, Portugal – 19%, Spain – 19%, Ireland – 18%, and Germany – 11%. For the U.S. in 2011, the penetration level was estimated at 3.3%.[72] To obtain 100% from wind annually requires substantial long term storage. On a monthly, weekly, daily, or hourly basis—or less—wind can supply as much as or more than 100% of current use, with the rest stored or exported. Seasonal industry can take advantage of high wind and low usage times such as at night when wind output can exceed normal demand. Such industry can include production of silicon, aluminum, steel, or of natural gas, and hydrogen, which allow long term storage, facilitating 100% energy from variable renewable energy.[73][74] Homes can also be programmed to accept extra electricity on demand, for example by remotely turning up water heater thermostats.[75]

Variability[edit]

Main article: Variable renewable energy

Windmills are typically installed in favourable windy locations. In the image, wind power generators in Spain, near an Osborne bull.

Electricity generated from wind power can be highly variable at several different timescales: hourly, daily, or seasonally. Annual variation also exists, but is not as significant. Because instantaneous electrical generation and consumption must remain in balance to maintain grid stability, this variability can present substantial challenges to incorporating large amounts of wind power into a grid system. Intermittency and the non-dispatchable nature of wind energy production can raise costs for regulation, incremental operating reserve, and (at high penetration levels) could require an increase in the already existing energy demand management, load shedding, storage solutions or system interconnection with HVDC cables.

Fluctuations in load and allowance for failure of large fossil-fuel generating units require reserve capacity that can also compensate for variability of wind generation.

Increase in system operation costs, Euros per MWh, for 10% & 20% wind share[6]

Country 10% 20%

Germany 2.5 3.2

Denmark 0.4 0.8

Finland 0.3 1.5

Norway 0.1 0.3

Sweden 0.3 0.7

Wind power is however, variable, but during low wind periods it can be replaced by other power sources. Transmission networks presently cope with outages of other generation plants and daily changes in electrical demand, but the variability of intermittent power sources such as wind power, are unlike those of conventional power generation plants which, when scheduled to be operating, may be able to deliver their nameplate capacity around 95% of the time.

Presently, grid systems with large wind penetration require a small increase in the frequency of usage of natural gas spinning reserve power plants to prevent a loss of electricity in the event that conditions are not favorable for power production from the wind. At lower wind power grid penetration, this is less of an issue.[76][77][78]

GE has installed a prototype wind turbine with onboard battery similar to that of an electric car, equivalent of 1 minute of production. Despite the small capacity, it is enough to guarantee that power output complies with forecast for 15 minutes, as the battery is used to eliminate the difference rather than provide full output. The increased predictability can be used to take wind power penetration from 20 to 30 or 40 per cent. The battery cost can be retrieved by selling burst power on demand and reducing backup needs from gas plants.[79]

A report on Denmark's wind power noted that their wind power network provided less than 1% of average demand on 54 days during the year 2002.[80] Wind power advocates argue that these periods of low wind can be dealt with by simply restarting existing power stations that have been held in readiness, or interlinking with HVDC.[81] Electrical grids with slow-responding thermal power plants and without ties to networks with hydroelectric generation may have to limit the use of wind power.[80] According to a 2007 Stanford University study published in the Journal of Applied Meteorology and Climatology, interconnecting ten or more wind farms can allow an average of 33% of the total energy produced (i.e. about 8% of total nameplate capacity) to be used as reliable, baseload electric power which can be relied on to handle peak loads, as long as minimum criteria are met for wind speed and turbine height.[82][83]

Conversely, on particularly windy days, even with penetration levels of 16%, wind power generation can surpass all other electricity sources in a country. In Spain, on 16 April 2012 wind power production reached the highest percentage of electricity production till then, with wind farms covering 60.46% of the total demand.[84] In Denmark, which had power market penetration of 30% in 2013, over 90 hours, wind power generated 100% of the countries power, peaking at 122% of the countries demand at 2am on the 28th October.[85]

A 2006 International Energy Agency forum presented costs for managing intermittency as a function of wind-energy's share of total capacity for several countries, as shown in the table on the right. Three reports on the wind variability in the UK issued in 2009, generally agree that variability of wind needs to be taken into account, but it does not make the grid unmanageable. The additional costs, which are modest, can be quantified.[7]

The combination of diversifying variable renewables by type and location, forecasting their variation, and integrating them with dispatchable renewables, flexible fueled generators, and demand response can create a power system that has the potential to meet power supply needs reliably. Integrating ever-higher levels of renewables is being successfully demonstrated in the real world:[86]

In 2009, eight American and three European authorities, writing in the leading electrical engineers' professional journal, didn't find "a credible and firm technical limit to the amount of wind energy that can be accommodated by electricity grids". In fact, not one of more than 200 international studies, nor official studies for the eastern and western U.S. regions, nor the International Energy Agency, has found major costs or technical barriers to reliably integrating up to 30% variable renewable supplies into the grid, and in some studies much more. – Reinventing Fire[86]

Solar power tends to be complementary to wind.[87][88] On daily to weekly timescales, high pressure areas tend to bring clear skies and low surface winds, whereas low pressure areas tend to be windier and cloudier. On seasonal timescales, solar energy peaks in summer, whereas in many areas wind energy is lower in summer and higher in winter.[nb 2][89] Thus the intermittencies of wind and solar power tend to cancel each other somewhat. In 2007 the Institute for Solar Energy Supply Technology of the University of Kassel pilot-tested a combined power plant linking solar, wind, biogas and hydrostorage to provide load-following power around the clock and throughout the year, entirely from renewable sources.[90]

Further information: Grid balancing

Predictability[edit]

Main article: Wind power forecasting

Wind power forecasting methods are used, but predictability of any particular wind farm is low for short-term operation. For any particular generator there is an 80% chance that wind output will change less than 10% in an hour and a 40% chance that it will change 10% or more in 5 hours.[91]

However, studies by Graham Sinden (2009) suggest that, in practice, the variations in thousands of wind turbines, spread out over several different sites and wind regimes, are smoothed. As the distance between sites increases, the correlation between wind speeds measured at those sites, decreases.[92]

Thus, while the output from a single turbine can vary greatly and rapidly as local wind speeds vary, as more turbines are connected over larger and larger areas the average power output becomes less variable and more predictable.[93]

Energy storage[edit]

Main article: Grid energy storage. See also: List of energy storage projects.

The Sir Adam Beck Generating Complex at Niagara Falls, Canada, includes a large pumped-storage hydroelectricity reservoir. During hours of low electrical demand excess electrical grid power is used to pump water up into the reservoir, which then provides an extra 174 MW of electricity during periods of peak demand.

Typically, conventional hydroelectricity complements wind power very well. When the wind is blowing strongly, nearby hydroelectric plants can temporarily hold back their water. When the wind drops they can, provided they have the generation capacity, rapidly increase production to compensate. This gives a very even overall power supply and virtually no loss of energy and uses no more water.

Alternatively, where a suitable head of water is not available, pumped-storage hydroelectricity or other forms of grid energy storage such as compressed air energy storage and thermal energy storage can store energy developed by high-wind periods and release it when needed.[94] The type of storage needed depends on the wind penetration level – low penetration requires daily storage, and high penetration requires both short and long term storage – as long as a month or more. Stored energy increases the economic value of wind energy since it can be shifted to displace higher cost generation during peak demand periods. The potential revenue from this arbitrage can offset the cost and losses of storage; the cost of storage may add 25% to the cost of any wind energy stored but it is not envisaged that this would apply to a large proportion of wind energy generated. For example, in the UK, the 1.7 GW Dinorwig pumped-storage plant evens out electrical demand peaks, and allows base-load suppliers to run their plants more efficiently. Although pumped-storage power systems are only about 75% efficient, and have high installation costs, their low running costs and ability to reduce the required electrical base-load can save both fuel and total electrical generation costs.[95][96]

In particular geographic regions, peak wind speeds may not coincide with peak demand for electrical power. In the U.S. states of California and Texas, for example, hot days in summer may have low wind speed and high electrical demand due to the use of air conditioning. Some utilities subsidize the purchase of geothermal heat pumps by their customers, to reduce electricity demand during the summer months by making air conditioning up to 70% more efficient;[97] widespread adoption of this technology would better match electricity demand to wind availability in areas with hot summers and low summer winds. A possible future option may be to interconnect widely dispersed geographic areas with an HVDC "super grid". In the U.S. it is estimated that to upgrade the transmission system to take in planned or potential renewables would cost at least $60 billion.[98]

Germany has an installed capacity of wind and solar that can exceed daily demand, and has been exporting peak power to neighboring countries, with exports which amounted to some 14.7 billion kilowatt hours in 2012.[99] A more practical solution is the installation of thirty days storage capacity able to supply 80% of demand, which will become necessary when most of Europe's energy is obtained from wind power and solar power. Just as the EU requires member countries to maintain 90 days strategic reserves of oil it can be expected that countries will provide electricity storage, instead of expecting to use their neighbors for net metering.[100]

Wind power hardly ever suffers major technical failures, since failures of individual wind turbines have hardly any effect on overall power, so that the distributed wind power is highly reliable and predictable,[101] whereas conventional generators, while far less variable, can suffer major unpredictable outages.

Capacity credit and fuel savings[edit]

The capacity credit of wind is estimated by determining the capacity of conventional plants displaced by wind power, whilst maintaining the same degree of system security,.[102] However, the precise value is irrelevant since the main value of wind is its fuel and CO

2 savings,[citation needed] and wind is not expected to be constantly available.[103]

Economics[edit]

Wind turbines reached grid parity (the point at which the cost of wind power matches traditional sources) in some areas of Europe in the mid-2000s, and in the US around the same time. Falling prices continue to drive the levelized cost down and it has been suggested that it has reached general grid parity in Europe in 2010, and will reach the same point in the US around 2016 due to an expected reduction in capital costs of about 12%.[1]

Cost trends[edit]

Estimated cost per MWh for wind power in Denmark

The National Renewable Energy Laboratory projects that the levelized cost of wind power in the U.S. will decline about 25% from 2012 to 2030.[104]

A turbine blade convoy passing through Edenfield in the U.K. (2008). Even longer two-piece blades are now manufactured, and then assembled on-site to reduce difficulties in transportation.

Wind power is capital intensive, but has no fuel costs.[105] The price of wind power is therefore much more stable than the volatile prices of fossil fuel sources.[106] The marginal cost of wind energy once a plant is constructed is usually less than 1-cent per kW·h.[107] This cost has additionally reduced as wind turbine technology has improved. There are now longer and lighter wind turbine blades, improvements in turbine performance and increased power generation efficiency. Also, wind project capital and maintenance costs have continued to decline.[108]

The estimated average cost per unit incorporates the cost of construction of the turbine and transmission facilities, borrowed funds, return to investors (including cost of risk), estimated annual production, and other components, averaged over the projected useful life of the equipment, which may be in excess of twenty years. Energy cost estimates are highly dependent on these assumptions so published cost figures can differ substantially. In 2004, wind energy cost a fifth of what it did in the 1980s, and some expected that downward trend to continue as larger multi-megawatt turbines were mass-produced.[109] As of 2012 capital costs for wind turbines are substantially lower than 2008–2010 but are still above 2002 levels.[110] A 2011 report from the American Wind Energy Association stated, "Wind's costs have dropped over the past two years, in the range of 5 to 6 cents per kilowatt-hour recently.... about 2 cents cheaper than coal-fired electricity, and more projects were financed through debt arrangements than tax equity structures last year.... winning more mainstream acceptance from Wall Street's banks.... Equipment makers can also deliver products in the same year that they are ordered instead of waiting up to three years as was the case in previous cycles.... 5,600 MW of new installed capacity is under construction in the United States, more than double the number at this point in 2010. Thirty-five percent of all new power generation built in the United States since 2005 has come from wind, more than new gas and coal plants combined, as power providers are increasingly enticed to wind as a convenient hedge against unpredictable commodity price moves."[111]

A British Wind Energy Association report gives an average generation cost of onshore wind power of around 3.2 pence (between US 5 and 6 cents) per kW·h (2005).[112] Cost per unit of energy produced was estimated in 2006 to be comparable to the cost of new generating capacity in the US for coal and natural gas: wind cost was estimated at $55.80 per MW·h, coal at $53.10/MW·h and natural gas at $52.50.[113] Similar comparative results with natural gas were obtained in a governmental study in the UK in 2011.[114] The presence of wind energy, even when subsidised, can reduce costs for consumers (€5 billion/yr in Germany) by reducing the marginal price, by minimising the use of expensive peaking power plants.[115]

In February 2013 Bloomberg New Energy Finance reported that the cost of generating electricity from new wind farms is cheaper than new coal or new baseload gas plants. When including the current Australian federal government carbon pricing scheme their modeling gives costs (in Australian dollars) of $80/MWh for new wind farms, $143/MWh for new coal plants and $116/MWh for new baseload gas plants. The modeling also shows that "even without a carbon price (the most efficient way to reduce economy-wide emissions) wind energy is 14% cheaper than new coal and 18% cheaper than new gas."[116] Part of the higher costs for new coal plants is due to high financial lending costs because of "the reputational damage of emissions-intensive investments". The expense of gas fired plants is partly due to "export market" effects on local prices. Costs of production from coal fired plants built in "the 1970s and 1980s" are cheaper than renewable energy sources because of depreciation.[116]

The wind industry in the USA is now able to produce more power at lower cost by using taller wind turbines with longer blades, capturing the faster winds at higher elevations. This has opened up new opportunities and in Indiana, Michigan, and Ohio, the price of power from wind turbines built 300 feet to 400 feet above the ground can now compete with conventional fossil fuels like coal. Prices have fallen to about 4 cents per kilowatt-hour in some cases and utilities have been increasing the amount of wind energy in their portfolio, saying it is their cheapest option.[117]

Incentives and community benefits[edit]

U.S. landowners typically receive $3,000–$5,000 annual rental income per wind turbine, while farmers continue to grow crops or graze cattle up to the foot of the turbines.[118] Shown: the Brazos Wind Farm in Texas.

Some of the 6,000 wind turbines in California's Altamont Pass Wind Farm aided by tax incentives during the 1980s.[119]

The U.S. wind industry generates tens of thousands of jobs and billions of dollars of economic activity.[120] Wind projects provide local taxes, or payments in lieu of taxes and strengthen the economy of rural communities by providing income to farmers with wind turbines on their land.[118][121] Wind energy in many jurisdictions receives financial or other support to encourage its development. Wind energy benefits from subsidies in many jurisdictions, either to increase its attractiveness, or to compensate for subsidies received by other forms of production which have significant negative externalities.

In the US, wind power receives a production tax credit (PTC) of 1.5¢/kWh in 1993 dollars for each kW·h produced, for the first ten years; at 2.2 cents per kW·h in 2012, the credit was renewed on 2 January 2012, to include construction begun in 2013.[122] A 30% tax credit can be applied instead of receiving the PTC.[123][124] Another tax benefit is accelerated depreciation. Many American states also provide incentives, such as exemption from property tax, mandated purchases, and additional markets for "green credits".[125] The Energy Improvement and Extension Act of 2008 contains extensions of credits for wind, including microturbines. Countries such as Canada and Germany also provide incentives for wind turbine construction, such as tax credits or minimum purchase prices for wind generation, with assured grid access (sometimes referred to as feed-in tariffs). These feed-in tariffs are typically set well above average electricity prices.[126][127] In December 2013 U.S. Senator Lamar Alexander and other Republican senators argued that the "wind energy production tax credit should be allowed to expire at the end of 2013."[128]

Secondary market forces also provide incentives for businesses to use wind-generated power, even if there is a premium price for the electricity. For example, socially responsible manufacturers pay utility companies a premium that goes to subsidize and build new wind power infrastructure. Companies use wind-generated power, and in return they can claim that they are undertaking strong "green" efforts. In the US the organization Green-e monitors business compliance with these renewable energy credits.[129]

Small-scale wind power[edit]

Further information: Microgeneration

A small Quietrevolution QR5 Gorlov type vertical axis wind turbine on the roof of Colston Hall in Bristol, England. Measuring 3 m in diameter and 5 m high, it has a nameplate rating of 6.5 kW.

Small-scale wind power is the name given to wind generation systems with the capacity to produce up to 50 kW of electrical power.[130] Isolated communities, that may otherwise rely on diesel generators, may use wind turbines as an alternative. Individuals may purchase these systems to reduce or eliminate their dependence on grid electricity for economic reasons, or to reduce their carbon footprint. Wind turbines have been used for household electricity generation in conjunction with battery storage over many decades in remote areas.[131]

Recent examples of small-scale wind power projects in an urban setting can be found in New York City, where, since 2009, a number of building projects have capped their roofs with Gorlov-type helical wind turbines. Although the energy they generate is small compared to the buildings' overall consumption, they help to reinforce the building's 'green' credentials in ways that "showing people your high-tech boiler" can not, with some of the projects also receiving the direct support of the New York State Energy Research and Development Authority.[132]

Grid-connected domestic wind turbines may use grid energy storage, thus replacing purchased electricity with locally produced power when available. The surplus power produced by domestic microgenerators can, in some jurisdictions, be fed into the network and sold to the utility company, producing a retail credit for the microgenerators' owners to offset their energy costs.[133][134]

Off-grid system users can either adapt to intermittent power or use batteries, photovoltaic or diesel systems to supplement the wind turbine. Equipment such as parking meters, traffic warning signs, street lighting, or wireless Internet gateways may be powered by a small wind turbine, possibly combined with a photovoltaic system, that charges a small battery replacing the need for a connection to the power grid.[135]

A Carbon Trust study into the potential of small-scale wind energy in the UK, published in 2010, found that small wind turbines could provide up to 1.5 terawatt hours (TW·h) per year of electricity (0.4% of total UK electricity consumption), saving 0.6 million tonnes of carbon dioxide (Mt CO2) emission savings. This is based on the assumption that 10% of households would install turbines at costs competitive with grid electricity, around 12 pence (US 19 cents) a kW·h.[136] A report prepared for the UK's government-sponsored Energy Saving Trust in 2006, found that home power generators of various kinds could provide 30 to 40% of the country's electricity needs by 2050.[137]

Distributed generation from renewable resources is increasing as a consequence of the increased awareness of climate change. The electronic interfaces required to connect renewable generation units with the utility system can include additional functions, such as the active filtering to enhance the power quality.[138]

Environmental effects[edit]

Main article: Environmental impact of wind power

According to the manager of this wind farm, livestock ignore wind turbines,[139] and continue to graze as they did before wind turbines were installed.

Compared to the environmental impact of traditional energy sources, the environmental impact of wind power is relatively minor in terms of pollution. Wind power consumes no fuel, and emits no air pollution, unlike fossil fuel power sources. The energy consumed to manufacture and transport the materials used to build a wind power plant is equal to the new energy produced by the plant within a few months. While a wind farm may cover a large area of land, many land uses such as agriculture are compatible, with only small areas of turbine foundations and infrastructure made unavailable for use.[140][141]

There are reports of bird and bat mortality at wind turbines as there are around other artificial structures. The scale of the ecological impact may[142] or may not[143] be significant, depending on specific circumstances. Although many artificial structures can kill birds, wind power has a disproportionate effect on certain endangered bird species.[144] An especially vulnerable group are raptors, which are slow to reproduce and favor the high wind speed corridors that wind turbine companies build turbines in, to maximize energy production.[144] Although they have a negligible effect on most birds, in some locations there is a disproportionate effects on some birds of conservation concern, such as the golden eagle and raptor species.[144]

However, a large meta-analysis of 616 individual studies on electricity production and its effects on avian mortality concluded that the most visible impacts of wind technology are not necessarily the most flagrant ones, as:[145]

“

Wind turbines seem to present a significant threat as all their negative externalities are concentrated in one place, while those from conventional and nuclear fuel cycles are spread out across space and time. Avian mortality and wind energy has consequently received far more attention and research than the avian deaths associated with coal, oil, natural gas and nuclear power generators [although] study suggests that wind energy may be the least harmful to birds.

”

Prevention and mitigation of wildlife fatalities, and protection of peat bogs,[146] affect the siting and operation of wind turbines.

There are anecdotal reports of negative effects from noise on people who live very close to wind turbines. Peer-reviewed research has generally not supported these statements.[147]

Politics[edit]

Central government[edit]

Part of the Seto Hill Windfarm in Japan, one of several windfarms that continued generating without interruption after the severe 2011 earthquake and tsunami followed by the Fukushima nuclear disaster.

Nuclear power and fossil fuels are subsidized by many governments, and wind power and other forms of renewable energy are also often subsidized. For example a 2009 study by the Environmental Law Institute[148] assessed the size and structure of U.S. energy subsidies over the 2002–2008 period. The study estimated that subsidies to fossil-fuel based sources amounted to approximately $72 billion over this period and subsidies to renewable fuel sources totalled $29 billion. In the United States, the federal government has paid US$74 billion for energy subsidies to support R&D for nuclear power ($50 billion) and fossil fuels ($24 billion) from 1973 to 2003. During this same time frame, renewable energy technologies and energy efficiency received a total of US$26 billion. It has been suggested that a subsidy shift would help to level the playing field and support growing energy sectors, namely solar power, wind power, and biofuels.[149] History shows that no energy sector was developed without subsidies.[149]

According to the International Energy Agency (IEA) (2011), energy subsidies artificially lower the price of energy paid by consumers, raise the price received by producers or lower the cost of production. "Fossil fuels subsidies costs generally outweigh the benefits. Subsidies to renewables and low-carbon energy technologies can bring long-term economic and environmental benefits".[150] In November 2011, an IEA report entitled Deploying Renewables 2011 said "subsidies in green energy technologies that were not yet competitive are justified in order to give an incentive to investing into technologies with clear environmental and energy security benefits". The IEA's report disagreed with claims that renewable energy technologies are only viable through costly subsidies and not able to produce energy reliably to meet demand.

In the U.S., the wind power industry has recently increased its lobbying efforts considerably, spending about $5 million in 2009 after years of relative obscurity in Washington.[151] By comparison, the U.S. nuclear industry alone spent over $650 million on its lobbying efforts and campaign contributions during a single ten-year period ending in 2008.[152][153][154]

Following the 2011 Japanese nuclear accidents, Germany's federal government is working on a new plan for increasing energy efficiency and renewable energy commercialization, with a particular focus on offshore wind farms. Under the plan, large wind turbines will be erected far away from the coastlines, where the wind blows more consistently than it does on land, and where the enormous turbines won't bother the inhabitants. The plan aims to decrease Germany's dependence on energy derived from coal and nuclear power plants.[155]

Public opinion[edit]

Environmental group members are both more in favor of wind power (74%) as well as more opposed (24%). Few are undecided.

Surveys of public attitudes across Europe and in many other countries show strong public support for wind power.[156][157][158] About 80% of EU citizens support wind power.[159] In Germany, where wind power has gained very high social acceptance, hundreds of thousands of people have invested in citizens' wind farms across the country and thousands of small and medium sized enterprises are running successful businesses in a new sector that in 2008 employed 90,000 people and generated 8% of Germany's electricity.[160][161] Although wind power is a popular form of energy generation, the construction of wind farms is not universally welcomed, often for aesthetic reasons.[140][156][157][158][159][162][163]

In Spain, with some exceptions, there has been little opposition to the installation of inland wind parks. However, the projects to build offshore parks have been more controversial.[164] In particular, the proposal of building the biggest offshore wind power production facility in the world in southwestern Spain in the coast of Cádiz, on the spot of the 1805 Battle of Trafalgar.[165] has been met with strong opposition who fear for tourism and fisheries in the area,[166] and because the area is a war grave.[165]

Which should be increased in Scotland?[167]

In a survey conducted by Angus Reid Strategies in October 2007, 89 per cent of respondents said that using renewable energy sources like wind or solar power was positive for Canada, because these sources were better for the environment. Only 4 per cent considered using renewable sources as negative since they can be unreliable and expensive.[168] According to a Saint Consulting survey in April 2007, wind power was the alternative energy source most likely to gain public support for future development in Canada, with only 16% opposed to this type of energy. By contrast, 3 out of 4 Canadians opposed nuclear power developments.[169]

A 2003 survey of residents living around Scotland's 10 existing wind farms found high levels of community acceptance and strong support for wind power, with much support from those who lived closest to the wind farms. The results of this survey support those of an earlier Scottish Executive survey 'Public attitudes to the Environment in Scotland 2002', which found that the Scottish public would prefer the majority of their electricity to come from renewables, and which rated wind power as the cleanest source of renewable energy.[170] A survey conducted in 2005 showed that 74% of people in Scotland agree that wind farms are necessary to meet current and future energy needs. When people were asked the same question in a Scottish renewables study conducted in 2010, 78% agreed. The increase is significant as there were twice as many wind farms in 2010 as there were in 2005. The 2010 survey also showed that 52% disagreed with the statement that wind farms are "ugly and a blot on the landscape". 59% agreed that wind farms were necessary and that how they looked was unimportant.[171] Scotland is planning to obtain 100% of electricity from renewable sources by 2020.[172]

In other cases there is direct community ownership of wind farm projects. In Germany, hundreds of thousands of people have invested in citizens' wind farms across the country and thousands of small and medium sized enterprises are running successful businesses in a new sector that in 2008 employed 90,000 people and generated 8 percent of Germany's electricity.[173] Wind power has gained very high social acceptance in Germany.[174] Surveys of public attitudes across Europe and in many other countries show strong public support for wind power.[156][157][175]

Opinion on increase in number of wind farms, 2010 Harris Poll[176]

U.S. Great

Britain France Italy Spain Germany

% % % % % %

Strongly oppose 3 6 6 2 2 4

Oppose more than favour 9 12 16 11 9 14

Favour more than oppose 37 44 44 38 37 42

Strongly favour 50 38 33 49 53 40

Community[edit]

See also: Community debate about wind farms

Wind turbines such as these, in Cumbria, England, have been opposed for a number of reasons, including aesthetics, by some sectors of the population.[177][178]

Many wind power companies work with local communities to reduce environmental and other concerns associated with particular wind farms.[179][180][181] In other cases there is direct community ownership of wind farm projects. Appropriate government consultation, planning and approval procedures also help to minimize environmental risks.[156][182][183] Some may still object to wind farms[184] but, according to The Australia Institute, their concerns should be weighed against the need to address the threats posed by climate change and the opinions of the broader community.[185]

In America, wind projects are reported to boost local tax bases, helping to pay for schools, roads and hospitals. Wind projects also revitalize the economy of rural communities by providing steady income to farmers and other landowners.[118]

In the UK, both the National Trust and the Campaign to Protect Rural England have expressed concerns about the effects on the rural landscape caused by inappropriately sited wind turbines and wind farms.[186][187]

Some wind farms have become tourist attractions. The Whitelee Wind Farm Visitor Centre has an exhibition room, a learning hub, a café with a viewing deck and also a shop. It is run by the Glasgow Science Centre.[188]

In Denmark, a loss-of-value scheme gives people the right to claim compensation for loss of value of their property if it is caused by proximity to a wind turbine. The loss must be at least 1% of the property's value.[189]

Despite this general support for the concept of wind power in the public at large, local opposition often exists and has delayed or aborted a number of projects.[190][191][192]

While aesthetic issues are subjective and some find wind farms pleasant and optimistic, or symbols of energy independence and local prosperity, protest groups are often formed to attempt to block new wind power sites for various reasons.[184][193][194]

This type of opposition is often described as NIMBYism,[195] but research carried out in 2009 found that there is little evidence to support the belief that residents only object to renewable power facilities such as wind turbines as a result of a "Not in my Back Yard" attitude.[196]

Turbine design[edit]

Main articles: Wind turbine and Wind turbine design. See also: Wind turbine aerodynamics.

Typical wind turbine components : 1-Foundation, 2-Connection to the electric grid, 3-Tower, 4-Access ladder, 5-Wind orientation control (Yaw control), 6-Nacelle, 7-Generator, 8-Anemometer, 9-Electric or Mechanical Brake, 10-Gearbox, 11-Rotor blade, 12-Blade pitch control, 13-Rotor hub.

Wind turbines are devices that convert the wind's kinetic energy into electrical power. The result of over a millennium of windmill development and modern engineering, today's wind turbines are manufactured in a wide range of horizontal axis and vertical axis types. The smallest turbines are used for applications such as battery charging for auxiliary power. Slightly larger turbines can be used for making small contributions to a domestic power supply while selling unused power back to the utility supplier via the electrical grid. Arrays of large turbines, known as wind farms, have become an increasingly important source of renewable energy and are used in many countries as part of a strategy to reduce their reliance on fossil fuels.

Wind turbine design is the process of defining the form and specifications of a wind turbine to extract energy from the wind.[197] A wind turbine installation consists of the necessary systems needed to capture the wind's energy, point the turbine into the wind, convert mechanical rotation into electrical power, and other systems to start, stop, and control the turbine.

In 1919 the physicist Albert Betz showed that for a hypothetical ideal wind-energy extraction machine, the fundamental laws of conservation of mass and energy allowed no more than 16/27 (59.3%) of the kinetic energy of the wind to be captured. This Betz limit can be approached in modern turbine designs, which may reach 70 to 80% of the theoretical Betz limit.[198][199]

The aerodynamics of a wind turbine are not straightforward. The air flow at the blades is not the same as the airflow far away from the turbine. The very nature of the way in which energy is extracted from the air also causes air to be deflected by the turbine. In addition the aerodynamics of a wind turbine at the rotor surface exhibit phenomena that are rarely seen in other aerodynamic fields. The shape and dimensions of the blades of the wind turbine are determined by the aerodynamic performance required to efficiently extract energy from the wind, and by the strength required to resist the forces on the blade.[200]

In addition to the aerodynamic design of the blades, the design of a complete wind power system must also address the design of the installation's rotor hub, nacelle, tower structure, generator, controls, and foundation.[201] Further design factors must also be considered when integrating wind turbines into electrical power grids.

Wind energy[edit]

Wind energy is the kinetic energy of air in motion, also called wind. Total wind energy flowing through an imaginary area A during the time t is:

E = \frac{1}{2}mv^2 = \frac{1}{2}(Avt\rho)v^2 = \frac{1}{2}At\rho v^3,[202]

where ρ is the density of air; v is the wind speed; Avt is the volume of air passing through A (which is considered perpendicular to the direction of the wind); Avtρ is therefore the mass m passing through "A". Note that ½ ρv2 is the kinetic energy of the moving air per unit volume.

Power is energy per unit time, so the wind power incident on A (e.g. equal to the rotor area of a wind turbine) is:

P = \frac{E}{t} = \frac{1}{2}A\rho v^3.[202]

Map of available wind power for the United States. Color codes indicate wind power density class. (click to see larger)

Distribution of wind speed (red) and energy (blue) for all of 2002 at the Lee Ranch facility in Colorado. The histogram shows measured data, while the curve is the Rayleigh model distribution for the same average wind speed.

Wind power in an open air stream is thus proportional to the third power of the wind speed; the available power increases eightfold when the wind speed doubles. Wind turbines for grid electricity therefore need to be especially efficient at greater wind speeds.

Wind is the movement of air across the surface of the Earth, affected by areas of high pressure and of low pressure.[203] The surface of the Earth is heated unevenly by the Sun, depending on factors such as the angle of incidence of the sun's rays at the surface (which differs with latitude and time of day) and whether the land is open or covered with vegetation. Also, large bodies of water, such as the oceans, heat up and cool down slower than the land. The heat energy absorbed at the Earth's surface is transferred to the air directly above it and, as warmer air is less dense than cooler air, it rises above the cool air to form areas of high pressure and thus pressure differentials. The rotation of the Earth drags the atmosphere around with it causing turbulence. These effects combine to cause a constantly varying pattern of winds across the surface of the Earth.[203]

The total amount of economically extractable power available from the wind is considerably more than present human power use from all sources.[204] Axel Kleidon of the Max Planck Institute in Germany, carried out a "top down" calculation on how much wind energy there is, starting with the incoming solar radiation that drives the winds by creating temperature differences in the atmosphere. He concluded that somewhere between 18 TW and 68 TW could be extracted.[205]

Cristina Archer and Mark Z. Jacobson presented a "bottom-up" estimate, which unlike Kleidon's are based on actual measurements of wind speeds, and found that there is 1700 TW of wind power at an altitude of 100 metres over land and sea. Of this, "between 72 and 170 TW could be extracted in a practical and cost-competitive manner".[205] They later estimated 80 TW.[206] However research at Harvard University estimates 1 Watt/m2 on average and 2–10 MW/km2 capacity for large scale wind farms, suggesting that these estimates of total global wind resources are too high by a factor of about 4.[207]

The strength of wind varies, and an average value for a given location does not alone indicate the amount of energy a wind turbine could produce there. To assess the frequency of wind speeds at a particular location, a probability distribution function is often fit to the observed data. Different locations will have different wind speed distributions. The Weibull model closely mirrors the actual distribution of hourly/ten-minute wind speeds at many locations. The Weibull factor is often close to 2 and therefore a Rayleigh distribution can be used as a less accurate, but simpler model.[208]

tenaga angin

Dari Wikipedia, ensiklopedia bebas

Burbo Bank Offshore Wind Farm, di pintu masuk ke Sungai Mersey di barat laut Inggris.

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energi yang berkelanjutan

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energi terbarukan

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v t e

Tenaga angin adalah konversi energi angin menjadi bentuk yang berguna energi, seperti menggunakan turbin angin untuk menghasilkan tenaga listrik, kincir angin untuk tenaga mekanik, windpumps untuk memompa air atau drainase, atau layar untuk mendorong kapal.

Peternakan angin besar terdiri dari ratusan turbin angin individu yang terhubung ke jaringan transmisi tenaga listrik. Untuk konstruksi baru, angin darat merupakan sumber yang murah listrik, kompetitif dengan atau di banyak tempat lebih murah daripada bahan bakar fosil tanaman. [1] [2] lepas pantai angin stabil dan lebih kuat dari di darat, dan peternakan lepas pantai memiliki dampak yang lebih rendah visual, tetapi biaya konstruksi dan pemeliharaan jauh lebih tinggi. Peternakan angin darat kecil dapat memberi makan beberapa energi ke dalam grid atau menyediakan listrik untuk terisolasi off-grid lokasi. [3]

Tenaga angin, sebagai alternatif untuk bahan bakar fosil, berlimpah, terbarukan, didistribusikan secara luas, bersih, tidak menghasilkan emisi gas rumah kaca selama operasi dan menggunakan lahan kecil. [4] Efek pada lingkungan umumnya kurang bermasalah dibandingkan dari sumber daya lain . Pada 2011, Denmark adalah menghasilkan lebih dari seperempat dari listrik dari angin dan 83 negara di seluruh dunia menggunakan tenaga angin untuk memasok jaringan listrik. [5] Pada tahun 2010 produksi energi angin lebih dari 2,5% dari total penggunaan listrik di seluruh dunia, dan berkembang pesat di lebih dari 25% per tahun.

Energi angin sangat konsisten dari tahun ke tahun tetapi memiliki variasi yang signifikan dari skala waktu yang lebih pendek. Sebagai proporsi windpower di suatu daerah meningkat, kebutuhan untuk meng-upgrade grid, dan kemampuan diturunkan untuk menggantikan produksi konvensional dapat terjadi. [6] [7] teknik manajemen daya seperti memiliki kapasitas penyimpanan berlebih, turbin didistribusikan secara geografis, dukungan dispatchable sumber, penyimpanan [8] Selain itu, prakiraan cuaca memungkinkan jaringan listrik yang akan disiapkan untuk diprediksi seperti pembangkit listrik tenaga air dipompa-storage, mengekspor dan mengimpor listrik ke daerah-daerah tetangga atau mengurangi permintaan saat produksi angin rendah, dapat sangat mengurangi masalah ini. variasi produksi yang terjadi. [9] [10] Energi angin dapat dianggap sebagai topik dalam eolics diterapkan. [11]

Isi [hide]

1 Sejarah

2 peternakan angin

2.1 Feeding ke dalam grid

2.2 tenaga angin lepas pantai

Kapasitas daya 3 Angin dan produksi

3,1 tren Pertumbuhan

Faktor 3.2 Kapasitas

3.3 Penetrasi

3.4 Variabilitas

3.5 Prediktabilitas

Penyimpanan 3.6 Energi

Kredit dan bahan bakar tabungan 3,7 Kapasitas

4 Ekonomi

4,1 tren Biaya

4.2 Insentif dan keuntungan bagi masyarakat

Tenaga angin 5 Kecil

6 Efek lingkungan

7 Politik

7.1 Pemerintah pusat

7.2 Opini publik

7.3 Masyarakat

Desain 8 Turbin

Energi 9 Angin

10 Lihat juga

11 Catatan

12 Referensi

13 Bacaan lebih lanjut

14 Pranala luar

Sejarah [sunting]

Artikel utama: Sejarah tenaga angin

Kincir angin Charles Brush murah dari 1888, yang digunakan untuk menghasilkan listrik.

Tenaga angin telah digunakan selama manusia telah menempatkan layar menjadi angin. Selama lebih dari dua mesin bertenaga angin ribuan tahun memiliki butiran tanah dan air dipompa. Tenaga angin yang tersedia secara luas dan tidak terbatas pada bank cepat mengalir sungai, atau lambat, membutuhkan sumber bahan bakar. Bertenaga angin pompa menguras polder Belanda, dan di daerah kering seperti Amerika pertengahan barat atau pedalaman Australia, pompa angin tersedia air untuk saham dan uap mesin hidup.

Kincir angin pertama kali digunakan untuk produksi listrik dibangun di Skotlandia pada bulan Juli 1887 oleh Prof James Blyth dari Anderson College, Glasgow (pendahulu dari Strathclyde University). [12] Blyth ini 10 m turbin tinggi, kain-berlayar angin dipasang di taman pondok liburannya di Marykirk di Kincardineshire dan digunakan untuk mengisi akumulator dikembangkan oleh Prancis Camille Alphonse Faure, untuk daya pencahayaan di pondok, [12] sehingga membuatnya rumah pertama di dunia yang telah listriknya dipasok oleh angin [13] Blyth menawarkan surplus listrik untuk rakyat Marykirk untuk penerangan jalan utama kekuasaan. namun, mereka menolak tawaran itu karena mereka pikir listrik adalah "pekerjaan setan." [12] Meskipun ia kemudian membangun angin turbin untuk memasok listrik darurat ke Lunatic Asylum lokal, Infirmary dan Apotik dari Montrose penemuan tidak pernah benar-benar tertangkap sebagai teknologi tidak dianggap ekonomis. [12]

Di seberang Atlantik, di Cleveland, Ohio yang lebih besar dan berat mesin direkayasa dirancang dan dibangun pada musim dingin tahun 1887-1888 oleh Charles F. Brush, [14] ini dibangun oleh perusahaan rekayasa di rumahnya dan dioperasikan dari 1886 sampai 1900 . [15] Sikat turbin angin memiliki rotor 17 m (56 kaki) dengan diameter dan dipasang pada 18 m (60 kaki) menara. Meskipun besar menurut standar sekarang, mesin itu hanya dinilai pada 12 kW. Dinamo yang terhubung digunakan baik untuk mengisi bank baterai atau untuk beroperasi hingga 100 pijar lampu, tiga lampu busur, dan berbagai motor di laboratorium Brush ini. [16]

Dengan perkembangan tenaga listrik, tenaga angin ditemukan aplikasi baru di pencahayaan bangunan jauh dari kekuasaan terpusat yang dihasilkan. Sepanjang abad ke-20 jalur paralel dikembangkan tanaman angin kecil cocok untuk pertanian atau tempat tinggal, dan lebih besar generator angin skala utilitas yang dapat dihubungkan ke jaringan listrik untuk penggunaan jarak jauh dari kekuasaan. Angin hari ini generator bertenaga beroperasi di setiap rentang ukuran antara tanaman kecil untuk pengisian daya baterai di tempat tinggal terisolasi, hingga dekat-gigawatt berukuran peternakan angin lepas pantai yang menyediakan listrik untuk jaringan listrik nasional.

Peternakan angin [sunting]

Artikel utama: pertanian angin dan Daftar peternakan angin darat.

Besar peternakan angin darat

Kincir angin sekarang

kapasitas

(MW) Negara Catatan

Gansu Wind Farm 6.000 Cina [17] [18]

Alta (Oak Creek-Mojave) 1320 Amerika Serikat [19]

Jaisalmer Wind Park 1064 India [20]

Shepherds datar Wind Farm 845 Amerika Serikat [21]

Roscoe Wind Farm 782 Amerika Serikat [22]

Kuda berongga Angin Energy Center 736 Amerika Serikat [23] [24]

Capricorn Ridge Wind Farm 662 Amerika Serikat [23] [24]

Fantanele-Cogealac Wind Farm 600 Rumania [25]

Fowler Ridge Wind Farm 600 Amerika Serikat [26]

Whitelee Wind Farm 539 Inggris [27]

Sebuah peternakan angin adalah sekelompok turbin angin di lokasi yang sama digunakan untuk produksi listrik. Sebuah peternakan angin yang besar dapat terdiri dari beberapa ratus turbin angin individu didistribusikan ke daerah diperpanjang, tetapi tanah antara turbin dapat digunakan untuk tujuan pertanian atau lainnya. Sebuah peternakan angin juga dapat terletak di lepas pantai.

Hampir semua turbin angin yang besar memiliki desain yang sama - sebuah turbin angin sumbu horisontal memiliki rotor melawan angin dengan tiga bilah, melekat pada nacelle di atas menara tubular tinggi.

Dalam sebuah peternakan angin, turbin individu saling berhubungan dengan tegangan menengah (sering 34,5 kV), sistem pengumpulan listrik dan jaringan komunikasi. Pada gardu, tegangan menengah arus listrik ini meningkat pada tegangan dengan transformator untuk koneksi ke tegangan tinggi listrik sistem transmisi daya. [Rujukan?]

Feeding ke dalam grid [sunting]

Generator induksi, sering digunakan untuk tenaga angin, membutuhkan daya reaktif untuk eksitasi sehingga gardu digunakan dalam sistem pengumpulan angin-daya termasuk bank kapasitor besar untuk koreksi faktor daya. [28] Berbagai jenis generator turbin angin berperilaku berbeda selama gangguan transmisi jaringan, begitu luas pemodelan karakteristik elektromekanis dinamis sebuah peternakan angin baru yang dibutuhkan oleh operator sistem transmisi untuk memastikan perilaku yang stabil diprediksi selama kesalahan sistem (lihat: naik tegangan rendah melalui). Secara khusus, generator induksi tidak dapat mendukung tegangan sistem selama kesalahan, seperti uap atau hidro-turbin generator sinkron. Mesin ganda makan umumnya memiliki sifat yang lebih diinginkan untuk interkoneksi grid. [29] [30] Sistem Transmisi operator akan menyediakan pengembang kincir angin dengan kode grid untuk menentukan persyaratan untuk interkoneksi ke jaringan transmisi. Ini akan mencakup faktor daya, keteguhan frekuensi dan perilaku dinamis dari turbin angin pertanian selama kesalahan sistem. [31] [32]

Tenaga angin lepas pantai [sunting]

Artikel utama: tenaga angin lepas pantai dan Daftar peternakan angin lepas pantai

Tenaga angin lepas pantai mengacu pada pembangunan peternakan angin di tubuh besar air untuk menghasilkan listrik. Instalasi ini dapat memanfaatkan angin lebih sering dan kuat yang tersedia di lokasi tersebut dan memiliki dampak estetika kurang pada lanskap dari proyek-proyek berbasis lahan. Namun, pembangunan dan biaya pemeliharaan jauh lebih tinggi. [33] [34]

Siemens dan Vestas adalah pemasok terkemuka untuk turbin tenaga angin lepas pantai. DONG Energy, Vattenfall dan E. ON yang operator lepas pantai terkemuka. [35] Pada Oktober 2010, 3.16 GW kapasitas tenaga angin lepas pantai operasional, terutama di Eropa Utara. Menurut BTM Consult, lebih dari 16 GW kapasitas tambahan akan dipasang sebelum akhir 2014 dan Inggris dan Jerman akan menjadi dua pasar terkemuka. Kapasitas tenaga angin lepas pantai diperkirakan akan mencapai total 75 GW di seluruh dunia pada tahun 2020, dengan kontribusi signifikan dari China dan Amerika Serikat. [35]

Pada akhir 2012, 1662 turbin di 55 peternakan angin lepas pantai di 10 negara Eropa yang menghasilkan 18 TWh, yang dapat kekuasaan hampir lima juta rumah tangga. [36] Pada Agustus 2013 Array London di Inggris adalah peternakan angin lepas pantai terbesar di dunia pada 630 MW. Ini diikuti dengan Greater Gabbard Wind Farm (504 MW), juga di Inggris. The Gwynt y Môr kincir angin (576 MW) adalah proyek terbesar saat ini sedang dibangun. [Rujukan?]

Kapasitas tenaga angin dan produksi [sunting]

Artikel utama: Tenaga angin menurut negara

Seluruh Dunia generasi angin sampai dengan tahun 2010

Seluruh dunia sekarang ada lebih dari dua ratus ribu turbin angin yang beroperasi, dengan kapasitas terpasang total 282.482 MW pada akhir 2012 [37] Uni Eropa sendiri melewati beberapa kapasitas terpasang 100.000 MW pada September 2012, [38] sementara Amerika Serikat melampaui 50.000 MW pada bulan Agustus 2012 dan grid terhubung kapasitas China melewati 50.000 MW pada bulan yang sama. [39] [40]

Kapasitas pembangkit angin dunia lebih dari empat kali lipat antara tahun 2000 dan 2006, dua kali lipat setiap tiga tahun. Amerika Serikat merintis peternakan angin dan memimpin dunia dalam kapasitas terpasang pada 1980-an dan 1990-an. Pada tahun 1997 kapasitas terpasang Jerman melampaui AS dan dipimpin sampai sekali lagi dikalahkan oleh Amerika Serikat pada tahun 2008 China telah berkembang pesat instalasi angin di tahun 2000-an dan melewati Amerika Serikat pada 2010 untuk menjadi pemimpin dunia.

Pada akhir tahun 2013, kapasitas terpasang di seluruh dunia generator bertenaga angin adalah 318 gigawatt (GW), tumbuh sebesar 35 GW dari tahun sebelumnya. [37] Menurut Asosiasi Energi Angin Dunia, sebuah organisasi industri, pada tahun 2010 tenaga angin yang dihasilkan 430 TWh atau sekitar 2,5% dari penggunaan listrik di seluruh dunia, [41] naik dari 1,5% pada tahun 2008 dan 0,1% pada tahun 1997 [42] Antara tahun 2005 dan 2010 pertumbuhan tahunan rata-rata di instalasi baru adalah 27,6%. [43] angin pasar tenaga penetrasi diperkirakan akan mencapai 3,35% pada tahun 2013 dan 8% pada tahun 2018. [43] [44]

Jumlah aktual listrik yang angin mampu menghasilkan dihitung dengan mengalikan kapasitas terpasang dengan faktor kapasitas, yang bervariasi sesuai dengan peralatan dan lokasi. Perkiraan faktor kapasitas untuk instalasi angin di kisaran 35% sampai 44%. [45]

Beberapa negara telah mencapai tingkat yang relatif tinggi penetrasi, seperti 28% dari stasioner (grid) produksi listrik di Denmark (2011), [46] 19% di Portugal (2011), [47] 16% di Spanyol (2011), [48] 16% di Irlandia (2012) [49] dan 8% di Jerman (2011). [50] pada 2011, 83 negara di seluruh dunia menggunakan tenaga angin secara komersial. [5]

Eropa menyumbang 48% dari total dunia kapasitas pembangkit tenaga angin pada tahun 2009 Pada tahun 2010, Spanyol menjadi produsen terkemuka Eropa energi angin, mencapai 42,976 GWh. Jerman memegang posisi teratas di Eropa dalam hal kapasitas terpasang, dengan total 27.215 MW per 31 Desember 2010 [51]

Top 10 negara

oleh kapasitas windpower rancang

(2013 akhir tahun) [37]

Negara Baru 2013

total kapasitas kapasitas (MW) Windpower

(MW)% dari total dunia

Cina 16.088 91.412 28,7

Amerika Serikat 1084 61091 19.2

Jerman 3.238 34.250 10.8

Spanyol 175 22959 7.2

India 1,729 20,150 6.3

UK 1883 10,531 3.3

Italia 444 8552 2.7

Prancis 631 8254 2.6

Kanada 1599 7803 2.5

Denmark 657 4772 1.5

(seluruh dunia) 7761 48332 15.2

Dunia Total 35.289 MW 318.105 MW 100%

Top 10 negara

oleh produksi listrik tenaga angin

(2012 total) [52]

Produksi Negara Windpower

(TWh)% dari total dunia

Amerika Serikat 140,9 26,4

Cina 118.1 22.1

Spanyol 49.1 9.2

Jerman 46.0 8.6

India 30.0 5.6

UK 19.6 3.7

Prancis 14.9 2.8

Italia 13.4 2.5

Kanada 11.8 2.2

Denmark 10.3 1.9

(seluruh dunia) 80.2 15.0

Dunia Total 534,3 TWh 100%

Tren pertumbuhan [sunting]

Seluruh dunia kapasitas terpasang 1997-2020 [MW], perkembangan dan prognosis. Sumber data: WWEA [53]

Seluruh dunia kapasitas daya terpasang angin perkiraan (Sumber: Global Dewan Energi Angin) [54] [55]

Pada tahun 2010, lebih dari setengah dari semua tenaga angin baru ditambahkan di luar pasar tradisional di Eropa dan Amerika Utara. Hal ini terutama dari konstruksi baru di Cina, yang menyumbang hampir setengah instalasi angin baru (16,5 GW). [56]

Solar energy

Global Dewan Energi Angin (GWEC) angka menunjukkan bahwa tahun 2007 mencatat kenaikan kapasitas terpasang 20 GW, mengambil total kapasitas terpasang energi angin untuk 94 GW, naik dari 74 GW pada tahun 2006 Meskipun kendala yang dihadapi rantai pasokan untuk turbin angin, tahunan pasar untuk angin terus meningkat pada tingkat diperkirakan 37%, menyusul pertumbuhan 32% pada tahun 2006 dalam hal nilai ekonomi, sektor energi angin telah menjadi salah satu pemain penting dalam pasar energi, dengan nilai total pembangkit baru peralatan yang dipasang pada tahun 2007 mencapai € 25 miliar atau US $ 36 miliar. [57]

Meskipun industri tenaga angin dipengaruhi oleh krisis keuangan global pada tahun 2009 dan 2010, BTM sebuah Konsultasikan lima tahun diperkirakan hingga 2.013 proyek pertumbuhan substansial. Selama lima tahun terakhir rata-rata pertumbuhan dalam instalasi baru telah 27,6% setiap tahun. Dalam perkiraan untuk 2013 tingkat pertumbuhan yang diharapkan rata-rata tahunan adalah 15,7%. [43] [44] Lebih dari 200 GW kapasitas tenaga angin baru bisa datang pada baris sebelum akhir 2014 Angin penetrasi pasar listrik diperkirakan akan mencapai 3,35% pada tahun 2013 dan 8% pada tahun 2018. [43] [44]

Kapasitas faktor [sunting]

Karena kecepatan angin tidak konstan, produksi energi tahunan sebuah peternakan angin adalah tidak pernah sebanyak jumlah dari peringkat pembangkit papan nama dikalikan dengan jumlah jam dalam setahun. Rasio produktivitas aktual dalam setahun untuk maksimum teoritis ini disebut faktor kapasitas. Faktor kapasitas tipikal adalah 15-50%; nilai-nilai pada batas atas dari kisaran yang dicapai di lokasi yang menguntungkan dan karena perbaikan desain turbin angin. [58] [59] [nb 1]

Data Online tersedia untuk beberapa lokasi, dan faktor kapasitas dapat dihitung dari output tahunan. [60] [61] Sebagai contoh, Jerman kapasitas tenaga angin rata-rata faktor nasional atas semua 2012 hanya di bawah 17,5% (45.867 GW · h / tahun / (29.9 GW × 24 × 366) = 0,1746), [62] dan faktor kapasitas peternakan angin Skotlandia rata-rata 24% antara 2008 dan 2010 [63]

Tidak seperti bahan bakar pembangkit listrik, faktor kapasitas dipengaruhi oleh beberapa parameter, termasuk variabilitas angin di lokasi dan ukuran generator relatif terhadap daerah turbin menyapu. Sebuah generator kecil akan lebih murah dan mencapai faktor kapasitas yang lebih tinggi tapi akan menghasilkan lebih sedikit listrik (dan dengan demikian lebih sedikit profit) dalam angin kencang. Sebaliknya, generator besar akan lebih mahal tapi menghasilkan tenaga ekstra dan, tergantung pada jenis, mungkin kios keluar pada kecepatan angin rendah. Dengan demikian faktor kapasitas optimum sekitar 40-50% akan ditujukan untuk. [59] [64]

Dalam studi 2008 yang dirilis oleh Departemen Energi AS Kantor Efisiensi Energi dan Energi Terbarukan, faktor kapasitas dicapai oleh armada turbin angin AS terbukti meningkat sebagai teknologi membaik. Kapasitas Faktor dicapai dengan turbin angin baru pada tahun 2010 mencapai hampir 40%. [65] [66]

Penetrasi [sunting]

Sebuah panorama Britania Raya Whitelee Wind Farm dengan Lochgoin Reservoir di latar depan.

Penetrasi Energi angin mengacu pada fraksi energi yang dihasilkan oleh angin dibandingkan dengan total kapasitas pembangkitan yang tersedia. Tidak ada tingkat maksimum yang berlaku umum penetrasi angin. Batas untuk grid tertentu akan tergantung pada tanaman menghasilkan yang ada, penentuan harga mekanisme, kapasitas untuk penyimpanan energi, manajemen permintaan dan faktor lainnya. Sebuah jaringan listrik interkoneksi sudah akan mencakup pembangkit cadangan dan kapasitas transmisi untuk memungkinkan kegagalan peralatan. Kapasitas cadangan ini juga dapat berfungsi untuk mengkompensasi pembangkit listrik yang bervariasi dihasilkan oleh tanaman angin. Penelitian telah menunjukkan bahwa 20% dari total konsumsi energi tahunan listrik dapat digabungkan dengan sedikit kesulitan. [67] Studi-studi ini telah untuk lokasi dengan peternakan angin geografis, beberapa derajat energi dispatchable atau tenaga air dengan kapasitas penyimpanan, manajemen permintaan, dan saling berhubungan ke daerah grid besar memungkinkan ekspor listrik bila diperlukan. Di luar tingkat 20%, ada beberapa batasan teknis, tetapi implikasi ekonomi menjadi lebih signifikan. Utilitas listrik terus mempelajari efek penetrasi skala besar generasi angin pada stabilitas sistem dan ekonomi. [68] [69] [70] [71]

Seorang tokoh penetrasi energi angin dapat ditentukan untuk jangka waktu yang berbeda waktu. Pada dasar tahunan, seperti tahun 2011, beberapa sistem jaringan memiliki tingkat penetrasi di atas 5%: Denmark - 29%, Portugal - 19%, Spanyol - 19%, Irlandia - 18%, dan Jerman - 11%. Bagi AS pada tahun 2011, tingkat penetrasi diperkirakan 3,3%. [72] Untuk mendapatkan 100% dari angin setiap tahunnya membutuhkan penyimpanan jangka panjang yang besar. Pada bulanan, mingguan, harian, atau per jam dasar-atau kurang-angin dapat menyediakan sebanyak atau lebih dari 100% dari penggunaan saat ini, dengan sisa disimpan atau diekspor. Industri musiman dapat mengambil keuntungan dari angin kencang dan penggunaan rendah kali seperti pada malam hari ketika output angin dapat melebihi permintaan normal. Industri tersebut dapat mencakup produksi silikon, aluminium, baja, atau gas alam, dan hidrogen, yang memungkinkan penyimpanan jangka panjang, memfasilitasi 100% energi dari energi terbarukan variabel. [73] [74] Homes juga dapat diprogram untuk menerima listrik tambahan pada permintaan, misalnya dengan jarak jauh menyalakan termostat pemanas air. [75]

Variabilitas [sunting]

Artikel utama: energi terbarukan Variable

Kincir angin biasanya dipasang di lokasi yang berangin menguntungkan. Dalam gambar, generator tenaga angin di Spanyol, dekat banteng Osborne.

Listrik yang dihasilkan dari tenaga angin dapat sangat bervariasi di beberapa skala waktu yang berbeda: per jam, harian, atau musiman. Variasi tahunan juga ada, tapi tidak signifikan. Karena generasi listrik sesaat dan konsumsi harus tetap seimbang untuk menjaga stabilitas grid, variabilitas ini dapat hadir tantangan besar untuk menggabungkan sejumlah besar tenaga angin ke dalam sistem grid. Intermittency dan sifat non-dispatchable produksi energi angin dapat meningkatkan biaya untuk regulasi, cadangan operasi tambahan, dan (pada tingkat penetrasi yang tinggi) bisa memerlukan peningkatan pengelolaan permintaan energi yang sudah ada, load shedding, solusi penyimpanan atau sistem interkoneksi dengan HVDC kabel.

Fluktuasi beban dan penyisihan kegagalan besar bahan bakar fosil pembangkit unit membutuhkan kapasitas cadangan yang juga dapat mengimbangi variabilitas generasi angin.

Kenaikan biaya operasi sistem, euro per MWh, 10% & 20% pangsa angin [6]

Negara 10% 20%

Jerman 2.5 3.2

Denmark 0.4 0.8

Finlandia 0.3 1.5

Norwegia 0.1 0.3

Swedia 0.3 0.7

Tenaga angin adalah Namun, variabel, tetapi selama periode angin rendah dapat digantikan oleh sumber daya lainnya. Jaringan Transmisi saat mengatasi pemadaman dari pembangkit lain dan perubahan harian dalam permintaan listrik, tetapi variabilitas sumber daya intermiten seperti tenaga angin, tidak seperti orang-orang dari pembangkit listrik konvensional yang bila dijadwalkan akan beroperasi, mungkin dapat memberikan kapasitas terpasang mereka sekitar 95% dari waktu.

Saat ini, sistem grid dengan penetrasi angin yang besar memerlukan peningkatan kecil dalam frekuensi penggunaan gas alam pembangkit listrik berputar cadangan untuk mencegah kehilangan listrik dalam hal kondisi yang tidak menguntungkan untuk produksi listrik dari angin. Pada rendah angin penetrasi jaringan listrik, ini kurang dari sebuah isu. [76] [77] [78]

GE telah memasang turbin angin prototipe dengan baterai onboard, mirip dengan mobil listrik, yang setara dengan 1 menit produksi. Meskipun kapasitas kecil, itu sudah cukup untuk menjamin bahwa dipatuhi output daya dengan perkiraan selama 15 menit, seperti baterai digunakan untuk menghilangkan perbedaan daripada memberikan output penuh. Peningkatan prediktabilitas dapat digunakan untuk mengambil angin penetrasi daya dari 20 sampai 30 atau 40 persen. Biaya baterai dapat diambil dengan menjual daya meledak pada permintaan dan mengurangi kebutuhan cadangan dari pabrik gas. [79]

Sebuah laporan tentang tenaga angin Denmark mencatat bahwa jaringan tenaga angin mereka yang tersedia kurang dari 1% dari kebutuhan rata-rata 54 hari selama tahun 2002 [80] Energi angin pendukung berpendapat bahwa periode ini angin rendah dapat ditangani hanya dengan restart kekuasaan yang ada stasiun yang telah diselenggarakan dalam kesiapan, atau interlinking dengan HVDC. [81] grid listrik dengan pembangkit listrik termal lambat menanggapi dan tanpa hubungan dengan jaringan dengan generasi listrik tenaga air mungkin harus membatasi penggunaan tenaga angin. [80] Menurut 2007 penelitian Stanford University yang diterbitkan dalam Journal of Applied Meteorologi Klimatologi dan, interkoneksi sepuluh atau lebih peternakan angin dapat memungkinkan rata-rata 33% dari total energi yang dihasilkan (yaitu sekitar 8% dari total kapasitas terpasang) untuk digunakan sebagai terpercaya, beban-basis tenaga listrik yang dapat diandalkan untuk menangani beban puncak, asalkan kriteria minimum terpenuhi untuk kecepatan angin dan tinggi turbin. [82] [83]

Sebaliknya, pada hari-hari terutama berangin, bahkan dengan tingkat penetrasi 16%, pembangkit listrik angin dapat melampaui semua sumber listrik lain dalam suatu negara. Di Spanyol, pada 16 April 2012 tenaga angin produksi mencapai persentase tertinggi produksi listrik sampai kemudian, dengan peternakan angin yang meliputi 60,46% dari total permintaan. [84] Di Denmark, yang memiliki kekuatan penetrasi pasar sebesar 30% pada tahun 2013, lebih dari 90 jam, tenaga angin yang dihasilkan 100% dari kekuatan negara, memuncak pada 122% dari permintaan negara-negara di 02:00 pada tanggal 28 Oktober. [85]

A 2006 forum Badan Energi Internasional disajikan biaya untuk mengelola intermittency sebagai fungsi dari pangsa angin-energi murah dari total kapasitas untuk beberapa negara, seperti yang ditunjukkan pada tabel di sebelah kanan. Tiga laporan mengenai variabilitas angin di Inggris yang diterbitkan pada tahun 2009, umumnya sepakat bahwa variabilitas angin perlu diperhitungkan, tapi itu tidak membuat grid diatur. Biaya tambahan, yang sederhana, bisa diukur. [7]

Kombinasi diversifikasi energi terbarukan variabel berdasarkan jenis dan lokasi, peramalan variasi mereka, dan mengintegrasikan mereka dengan energi terbarukan dispatchable, fleksibel berbahan bakar generator, dan respon permintaan dapat membuat sistem kekuasaan yang memiliki potensi untuk memenuhi kebutuhan pasokan listrik andal. Mengintegrasikan tingkat yang semakin tinggi dari energi terbarukan sedang berhasil menunjukkan di dunia nyata: [86]

Pada tahun 2009, delapan Amerika dan tiga otoritas Eropa, menulis dalam jurnal profesional insinyur listrik terkemuka ', tidak menemukan "batas teknis yang kredibel dan tegas untuk jumlah energi angin yang dapat ditampung oleh jaringan listrik". Bahkan, bukan salah satu dari lebih dari 200 studi internasional, maupun studi resmi untuk timur dan barat wilayah AS, maupun Badan Energi Internasional, telah menemukan biaya besar atau hambatan teknis andal mengintegrasikan ke variabel 30% pasokan terbarukan ke dalam grid, dan dalam beberapa penelitian banyak lagi. - Reinventing Api [86]

Tenaga surya cenderung melengkapi angin. [87] [88] Pada setiap hari untuk rentang waktu mingguan, daerah tekanan tinggi cenderung membawa langit cerah dan angin permukaan rendah, sedangkan daerah tekanan rendah cenderung windier dan cloudier. Pada rentang waktu musiman, puncak energi surya di musim panas, sedangkan di banyak daerah angin energi lebih rendah di musim panas dan lebih tinggi di musim dingin. [Nb 2] [89] Dengan demikian intermittencies angin dan tenaga surya cenderung membatalkan satu sama lain agak. Pada tahun 2007 Institute for Solar Energy Pasokan Teknologi dari Universitas Kassel diuji-coba pembangkit listrik gabungan menghubungkan surya, angin, biogas dan hydrostorage untuk memberikan daya beban-mengikuti sepanjang waktu dan sepanjang tahun, seluruhnya dari sumber terbarukan. [90 ]

Informasi lebih lanjut: Grid balancing

Prediktabilitas [sunting]

Artikel utama: Angin daya peramalan

Angin metode peramalan daya yang digunakan, tetapi prediktabilitas dari setiap peternakan angin tertentu rendah untuk operasi jangka pendek. Untuk generator tertentu ada 80% kemungkinan bahwa output angin akan berubah kurang dari 10% dalam satu jam dan kesempatan 40% bahwa itu akan mengubah 10% atau lebih di 5 jam. [91]

Namun, penelitian oleh Graham Sinden (2009) menunjukkan bahwa, dalam prakteknya, variasi dalam ribuan turbin angin, tersebar di beberapa situs yang berbeda dan rezim angin, dihaluskan. Sebagai jarak antara situs meningkat, korelasi antara kecepatan angin diukur pada situs tersebut, menurun. [92]

Jadi, sementara output dari turbin tunggal dapat sangat bervariasi dan cepat karena kecepatan angin lokal bervariasi, karena lebih banyak turbin yang terhubung lebih dari lebih besar dan lebih besar daerah output daya rata-rata menjadi kurang bervariasi dan lebih dapat diprediksi. [93]

Penyimpanan energi [sunting]

Artikel utama: penyimpanan energi Grid. Lihat juga: Daftar proyek-proyek penyimpanan energi.

The Sir Adam Beck Membangkitkan Complex di Air Terjun Niagara, Kanada, termasuk dipompa penyimpanan listrik tenaga air waduk besar. Selama jam permintaan listrik kelebihan daya rendah jaringan listrik digunakan untuk memompa air ke dalam reservoir, yang kemudian memberikan tambahan 174 MW listrik selama periode permintaan puncak.

Biasanya, pembangkit listrik tenaga air konvensional melengkapi tenaga angin sangat baik. Ketika angin bertiup kuat, pembangkit listrik tenaga air di dekatnya sementara bisa menahan air mereka. Ketika angin turun mereka bisa, asalkan mereka memiliki kapasitas pembangkit, dengan cepat meningkatkan produksi untuk mengimbangi. Hal ini memberikan sangat bahkan keseluruhan power supply dan hampir tidak kehilangan energi dan tidak menggunakan lebih banyak air.

Atau, di mana kepala cocok air tidak tersedia, pembangkit listrik tenaga air dipompa-penyimpanan atau bentuk lain dari penyimpanan energi jaringan seperti penyimpanan energi udara kompresi dan penyimpanan energi panas dapat menyimpan energi yang dikembangkan oleh periode tinggi angin dan melepaskannya bila diperlukan. [94 ] Jenis penyimpanan yang dibutuhkan tergantung pada tingkat penetrasi angin - penetrasi yang rendah membutuhkan penyimpanan harian, dan penetrasi yang tinggi membutuhkan baik penyimpanan jangka pendek dan jangka panjang - selama satu bulan atau lebih. Energi yang tersimpan meningkatkan nilai ekonomi dari energi angin karena dapat digeser untuk menggantikan generasi biaya yang lebih tinggi selama periode permintaan puncak. Potensi pendapatan dari arbitrase ini dapat meringankan biaya dan kerugian penyimpanan; biaya penyimpanan dapat menambahkan 25% untuk biaya apapun energi angin yang tersimpan tetapi tidak dipertimbangkan bahwa hal ini akan berlaku untuk sebagian besar energi angin yang dihasilkan. Misalnya, di Inggris, 1,7 GW Dinorwig tanaman dipompa penyimpanan meratakan puncak permintaan listrik, dan memungkinkan pemasok beban dasar untuk menjalankan pabrik mereka lebih efisien. Meskipun sistem tenaga dipompa penyimpanan hanya sekitar 75% efisien, dan memiliki biaya instalasi yang tinggi, biaya operasional yang rendah dan kemampuan untuk mengurangi diperlukan listrik beban dasar dapat menghemat bahan bakar dan biaya total generasi listrik. [95] [96]

Di daerah geografis tertentu, kecepatan angin puncak mungkin tidak bertepatan dengan permintaan puncak untuk tenaga listrik. Di negara bagian California dan Texas, misalnya, hari-hari panas di musim panas mungkin memiliki kecepatan angin rendah dan permintaan listrik yang tinggi akibat penggunaan AC. Beberapa utilitas mensubsidi pembelian pompa panas bumi oleh pelanggan mereka, untuk mengurangi kebutuhan listrik selama musim panas dengan membuat AC hingga 70% lebih efisien; [97] adopsi teknologi ini akan lebih baik memenuhi permintaan listrik ketersediaan angin di daerah dengan musim panas yang panas dan angin musim panas yang rendah. Sebuah pilihan di masa depan mungkin untuk menghubungkan wilayah geografis tersebar luas dengan HVDC "super grid". Di AS diperkirakan bahwa untuk meng-upgrade sistem transmisi untuk mengambil di direncanakan atau energi terbarukan potensial akan biaya setidaknya $ 60 miliar. [98]

Jerman memiliki kapasitas terpasang angin dan matahari yang dapat melebihi permintaan harian, dan telah mengekspor puncak kekuasaan ke negara-negara tetangga, dengan ekspor sebesar 14,7 miliar kilowatt beberapa jam pada tahun 2012 [99] Solusi yang lebih praktis adalah pemasangan tiga puluh hari kapasitas penyimpanan mampu memasok 80% dari permintaan, yang akan menjadi perlu ketika sebagian energi Eropa diperoleh dari tenaga angin dan tenaga surya. Sama seperti Uni Eropa mengharuskan negara-negara anggota untuk mempertahankan 90 hari cadangan strategis minyak itu dapat diharapkan bahwa negara-negara akan menyediakan penyimpanan listrik, bukannya mengharapkan untuk menggunakan tetangga mereka untuk metering bersih. [100]

Tenaga angin hampir tidak pernah menderita kegagalan teknis utama, karena kegagalan turbin angin individu hampir tidak memiliki efek pada daya keseluruhan, sehingga tenaga angin didistribusikan sangat handal dan dapat diprediksi, [101] sedangkan generator konvensional, sedangkan variabel jauh lebih sedikit, bisa menderita besar padam tak terduga.

Kredit Kapasitas dan bahan bakar tabungan [sunting]

Kapasitas kredit angin diperkirakan dengan menentukan kapasitas pembangkit konvensional yang mengungsi akibat tenaga angin, sementara menjaga tingkat yang sama dari sistem keamanan,. [102] Namun, nilai yang tepat tidak relevan karena nilai utama angin bahan bakar dan CO

2 tabungan, [rujukan?] Dan angin tidak diharapkan akan selalu tersedia. [103]

Ekonomi [sunting]

Turbin angin mencapai paritas grid (titik di mana biaya tenaga angin sesuai sumber tradisional) di beberapa daerah di Eropa pada pertengahan 2000-an, dan di Amerika Serikat sekitar waktu yang sama. Penurunan harga terus mendorong biaya levelized bawah dan telah menyarankan bahwa pihaknya telah mencapai paritas umum jaringan di Eropa pada tahun 2010, dan akan mencapai titik yang sama di Amerika Serikat sekitar 2016 karena adanya penurunan yang diharapkan dalam biaya modal sekitar 12%. [1]

Tren biaya [sunting]

Perkiraan biaya per MWh tenaga angin di Denmark

The National Renewable Energy Laboratory memproyeksikan bahwa biaya levelized tenaga angin di AS akan menurun sekitar 25% dari tahun 2012 sampai 2030 [104]

Sebuah konvoi blade turbin melewati Edenfield di Inggris (2008).Even longer two-piece blades are now manufactured, and then assembled on-site to reduce difficulties in transportation.

Incentives and community benefits[edit]

Some of the 6,000 wind turbines in California's Altamont Pass Wind Farm aided by tax incentives during the 1980s.[119]

Small-scale wind power[edit]

Further information: Microgeneration

A small Quietrevolution QR5 Gorlov type vertical axis wind turbine on the roof of Colston Hall in Bristol, England. Measuring 3 m in diameter and 5 m high, it has a nameplate rating of 6.5 kW.

Efek lingkungan [sunting]

Main article: Environmental impact of wind power

According to the manager of this wind farm, livestock ignore wind turbines,[139] and continue to graze as they did before wind turbines were installed.

Prevention and mitigation of wildlife fatalities, and protection of peat bogs,[146] affect the siting and operation of wind turbines.

There are anecdotal reports of negative effects from noise on people who live very close to wind turbines. Peer-reviewed research has generally not supported these statements.[147]

Politik [sunting]

Central government[edit]

According to the International Energy Agency (IEA) (2011), energy subsidies artificially lower the price of energy paid by consumers, raise the price received by producers or lower the cost of production."Fossil fuels subsidies costs generally outweigh the benefits. Subsidies to renewables and low-carbon energy technologies can bring long-term economic and environmental benefits".[150] In November 2011, an IEA report entitled Deploying Renewables 2011 said "subsidies in green energy technologies that were not yet competitive are justified in order to give an incentive to investing into technologies with clear environmental and energy security benefits". Laporan IEA tidak setuju dengan klaim bahwa teknologi energi terbarukan hanya layak melalui subsidi mahal dan tidak mampu menghasilkan energi andal untuk memenuhi permintaan.

Public opinion[edit]

Environmental group members are both more in favor of wind power (74%) as well as more opposed (24%). Few are undecided.

Which should be increased in Scotland?[167]

Opinion on increase in number of wind farms, 2010 Harris Poll[176]

U.S. Great

Britain France Italy Spain Germany

% % % % % %

Strongly oppose 3 6 6 2 2 4

Oppose more than favour 9 12 16 11 9 14

Favour more than oppose 37 44 44 38 37 42

Strongly favour 50 38 33 49 53 40

Community[edit]

See also: Community debate about wind farms

Wind turbines such as these, in Cumbria, England, have been opposed for a number of reasons, including aesthetics, by some sectors of the population.[177][178]

Despite this general support for the concept of wind power in the public at large, local opposition often exists and has delayed or aborted a number of projects.[190][191][192]

Turbine design[edit]

Main articles: Wind turbine and Wind turbine design. See also: Wind turbine aerodynamics.

Wind energy[edit]

Wind energy is the kinetic energy of air in motion, also called wind. Total wind energy flowing through an imaginary area A during the time t is:

E = \frac{1}{2}mv^2 = \frac{1}{2}(Avt\rho)v^2 = \frac{1}{2}At\rho v^3,[202]

Power is energy per unit time, so the wind power incident on A (e.g. equal to the rotor area of a wind turbine) is:

P = \frac{E}{t} = \frac{1}{2}A\rho v^3.[202]

Map of available wind power for the United States. Color codes indicate wind power density class. (click to see larger)

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Monday, September 1, 2014

Unfinished journey (28)

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