Renewable energy

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

American President Barack Obama speaks at the DeSoto Next Generation Solar Energy Center, in the USA.

Renewable energy
Biofuel Biomass Geothermal Hydroelectricity Solar energy Tidal power Wave power Wind power
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Renewable energy is energy which comes from natural resources such as sunlight, wind, rain, tides, and geothermal heat, which are renewable (naturally replenished). In 2008, about 19% of global final energy consumption came from renewables, with 13% coming from traditional biomass, which is mainly used for heating, and 3.2% from hydroelectricity.^[1] New renewables (small hydro, modern biomass, wind, solar, geothermal, and biofuels) accounted for another 2.7% and are growing very rapidly.^[1] The share of renewables in electricity generation is around 18%, with 15% of global electricity coming from hydroelectricity and 3% from new renewables.^[1][2]

Wind power is growing at the rate of 30% annually, with a worldwide installed capacity of 157,900 megawatts (MW) in 2009,^[3][4] and is widely used in Europe, Asia, and the United States.^[5] At the end of 2009, cumulative global photovoltaic (PV) installations surpassed 21,000 MW^[6][7][8] and PV power stations are popular in Germany and Spain.^[9] Solar thermal power stations operate in the USA and Spain, and the largest of these is the 354 MW SEGS power plant in the Mojave Desert.^[10] The world's largest geothermal power installation is The Geysers in California, with a rated capacity of 750 MW. Brazil has one of the largest renewable energy programs in the world, involving production of ethanol fuel from sugar cane, and ethanol now provides 18% of the country's automotive fuel.^[11] Ethanol fuel is also widely available in the USA.

While many renewable energy projects are large-scale, renewable technologies are also suited to rural and remote areas, where energy is often crucial in human development.^[12] Globally, an estimated 3 million households get power from small solar PV systems. Micro-hydro systems configured into village-scale or county-scale mini-grids serve many areas.^[13] More than 30 million rural households get lighting and cooking from biogas made in household-scale digesters. Biomass cookstoves are used by 160 million households.^[13]

Climate change concerns, coupled with high oil prices, peak oil, and increasing government support, are driving increasing renewable energy legislation, incentives and commercialization.^[14] New government spending, regulation and policies helped the industry weather the 2009 economic crisis better than many other sectors.^[15]

Overview

2008 worldwide renewable-energy sources. Source: REN21^[16]

Renewable energy flows involve natural phenomena such as sunlight, wind, tides and geothermal heat, as the International Energy Agency explains:^[17]

Renewable energy is derived from natural processes that are replenished constantly. In its various forms, it derives directly from the sun, or from heat generated deep within the earth. Included in the definition is electricity and heat generated from solar, wind, ocean, hydropower, biomass, geothermal resources, and biofuels and hydrogen derived from renewable resources.

Renewable energy replaces conventional fuels in four distinct areas: power generation, hot water/ space heating, transport fuels, and rural (off-grid) energy services:^[18]

• Power generation. Renewable energy provides 18 percent of total electricity generation worldwide. Renewable power generators are spread across many countries, and wind power alone already provides a significant share of electricity in some areas: for example, 14 percent in the U.S. state of Iowa, 40 percent in the northern German state of Schleswig-Holstein, and 20 percent in Denmark. Some countries get most of their power from renewables, including Iceland (100 percent), Brazil (85 percent), Austria (62 percent), New Zealand (65 percent), and Sweden (54 percent).^[19]

• Heating. Solar hot water makes an important contribution in many countries, most notably in China, which now has 70 percent of the global total (180 GWth). Most of these systems are installed on multi-family apartment buildings and meet a portion of the hot water needs of an estimated 50–60 million households in China. Worldwide, total installed solar water heating systems meet a portion of the water heating needs of over 70 million households. The use of biomass for heating continues to grow as well. In Sweden, national use of biomass energy has surpassed that of oil. Direct geothermal for heating is also growing rapidly.^[19]

• Transport fuels. Renewable biofuels have contributed to a significant decline in oil consumption in the United States since 2006. The 93 billion liters of biofuels produced worldwide in 2009 displaced the equivalent of an estimated 68 billion liters of gasoline, equal to about 5 percent of world gasoline production.^[19]

Mainstream forms of renewable energy

Wind power

Airflows can be used to run wind turbines. Modern wind turbines range from around 600 kW to 5 MW of rated power, although turbines with rated output of 1.5–3 MW have become the most common for commercial use; the power output of a turbine is a function of the cube of the wind speed, so as wind speed increases, power output increases dramatically.^[20] Areas where winds are stronger and more constant, such as offshore and high altitude sites, are preferred locations for wind farms. Typical capacity factors are 20-40%, with values at the upper end of the range in particularly favourable sites.^[21][22]

Globally, the long-term technical potential of wind energy is believed to be five times total current global energy production, or 40 times current electricity demand. This could require large amounts of land to be used for wind turbines, particularly in areas of higher wind resources. Offshore resources experience mean wind speeds of ~90% greater than that of land, so offshore resources could contribute substantially more energy.^[23]

Wind power is renewable and produces no greenhouse gases during operation, such as carbon dioxide and methane.

Hydropower

The Hoover Dam when completed in 1936 was both the world's largest electric-power generating station and the world's largest concrete structure.

Energy in water can be harnessed and used. Since water is about 800 times denser than air,^[24][25] even a slow flowing stream of water, or moderate sea swell, can yield considerable amounts of energy. There are many forms of water energy:

• Hydroelectric energy is a term usually reserved for large-scale hydroelectric dams. Examples are the Grand Coulee Dam in Washington State and the Akosombo Dam in Ghana.
• Micro hydro systems are hydroelectric power installations that typically produce up to 100 kW of power. They are often used in water rich areas as a remote-area power supply (RAPS). There are many of these installations around the world, including several delivering around 50 kW in the Solomon Islands.
• Damless hydro systems derive kinetic energy from rivers and oceans without using a dam.
• Ocean energy describes all the technologies to harness energy from the ocean and the sea. This includes marine current power, ocean thermal energy conversion, and tidal power.

Solar energy

Monocrystalline solar cell.

Solar energy is the energy derived from the sun through the form of solar radiation. Solar powered electrical generation relies on photovoltaics and heat engines. A partial list of other solar applications includes space heating and cooling through solar architecture, daylighting, solar hot water, solar cooking, and high temperature process heat for industrial purposes.

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.

Biomass

Biomass (plant material) is a renewable energy source because the energy it contains comes from the sun. Through the process of photosynthesis, plants capture the sun's energy. When the plants are burned, they release the sun's energy they contain. In this way, biomass functions as a sort of natural battery for storing solar energy. As long as biomass is produced sustainably, with only as much used as is grown, the battery will last indefinitely.^[26]

In general there are two main approaches to using plants for energy production: growing plants specifically for energy use, and using the residues from plants that are used for other things. The best approaches vary from region to region according to climate, soils and geography.^[26]

Biofuel

Information on pump regarding ethanol fuel blend up to 10%, California.

Liquid biofuel is usually either bioalcohol such as bioethanol or an oil such as biodiesel.

Bioethanol is an alcohol made by fermenting the sugar components of plant materials and it is made mostly from sugar and starch crops. With advanced technology being developed, cellulosic biomass, such as trees and grasses, are also used as feedstocks for ethanol production. Ethanol can be used as a fuel for vehicles in its pure form, but it is usually used as a gasoline additive to increase octane and improve vehicle emissions. Bioethanol is widely used in the USA and in Brazil.

Biodiesel is made from vegetable oils, animal fats or recycled greases. Biodiesel can be used as a fuel for vehicles in its pure form, but it is usually used as a diesel additive to reduce levels of particulates, carbon monoxide, and hydrocarbons from diesel-powered vehicles. Biodiesel is produced from oils or fats using transesterification and is the most common biofuel in Europe.

Biofuels provided 1.8% of the world's transport fuel in 2008.^[27]

Geothermal energy

Krafla Geothermal Station in northeast Iceland

Geothermal energy is energy obtained by tapping the heat of the earth itself, both from kilometers deep into the Earth's crust in some places of the globe or from some meters in geothermal heat pump in all the places of the planet . It is expensive to build a power station but operating costs are low resulting in low energy costs for suitable sites. Ultimately, this energy derives from heat in the Earth's core.

Three types of power plants are used to generate power from geothermal energy: dry steam, flash, and binary. Dry steam plants take steam out of fractures in the ground and use it to directly drive a turbine that spins a generator. Flash plants take hot water, usually at temperatures over 200 °C, out of the ground, and allows it to boil as it rises to the surface then separates the steam phase in steam/water separators and then runs the steam through a turbine. In binary plants, the hot water flows through heat exchangers, boiling an organic fluid that spins the turbine. The condensed steam and remaining geothermal fluid from all three types of plants are injected back into the hot rock to pick up more heat.^{[citation needed]}

The geothermal energy from the core of the Earth is closer to the surface in some areas than in others. Where hot underground steam or water can be tapped and brought to the surface it may be used to generate electricity. Such geothermal power sources exist in certain geologically unstable parts of the world such as Chile, Iceland, New Zealand, United States, the Philippines and Italy. The two most prominent areas for this in the United States are in the Yellowstone basin and in northern California. Iceland produced 170 MW geothermal power and heated 86% of all houses in the year 2000 through geothermal energy. Some 8000 MW of capacity is operational in total.^{[citation needed]}

There is also the potential to generate geothermal energy from hot dry rocks. Holes at least 3 km deep are drilled into the earth. Some of these holes pump water into the earth, while other holes pump hot water out. The heat resource consists of hot underground radiogenic granite rocks, which heat up when there is enough sediment between the rock and the earths surface. Several companies in Australia are exploring this technology.^{[citation needed]}

Renewable energy commercialization

Growth of renewables

During the five-years from the end of 2004 through 2009, worldwide renewable energy capacity grew at rates of 10–60 percent annually for many technologies. For wind power and many other renewable technologies, growth accelerated in 2009 relative to the previous four years.^[18] More wind power capacity was added during 2009 than any other renewable technology. However, grid-connected PV increased the fastest of all renewables technologies, with a 60-percent annual average growth rate for the five-year period.^[18]

Economic trends

All forms of energy are expensive, but as time progresses, renewable energy generally gets cheaper,^[31][32] while fossil fuels generally get more expensive. Al Gore has explained that renewable energy technologies are declining in price for three main reasons:^[33]

First, once the renewable infrastructure is built, the fuel is free forever. Unlike carbon-based fuels, the wind and the sun and the earth itself provide fuel that is free, in amounts that are effectively limitless.

Second, while fossil fuel technologies are more mature, renewable energy technologies are being rapidly improved. So innovation and ingenuity give us the ability to constantly increase the efficiency of renewable energy and continually reduce its cost.

Third, once the world makes a clear commitment to shifting toward renewable energy, the volume of production will itself sharply reduce the cost of each windmill and each solar panel, while adding yet more incentives for additional research and development to further speed up the innovation process.^[33]

Wind power market

Wind power: worldwide installed capacity 1996-2008

At the end of 2009, worldwide wind farm capacity was 157,900 MW, representing an increase of 31 percent during the year,^[3] and wind power supplied some 1.3% of global electricity consumption.^[34] Wind power accounts for approximately 19% of electricity use in Denmark, 9% in Spain and Portugal, and 6% in Germany and the Republic of Ireland.^[35] The United States is an important growth area and installed U.S. wind power capacity reached 25,170 MW at the end of 2008.^[36] As of September 2009, the Roscoe Wind Farm (781 MW) is the world's largest wind farm.^[37]

As of 2009, the 209 megawatt (MW) Horns Rev 2 wind farm in Denmark is the world's largest offshore wind farm. The United Kingdom is the world's leading generator of offshore wind power, followed by Denmark.^[38]

New generation of solar thermal plants

Solar Towers from left: PS10, PS20.

Large solar thermal power stations include the 354 MW Solar Energy Generating Systems power plant in the USA, Nevada Solar One (USA, 64 MW), Andasol 1 (Spain, 50 MW), Andasol 2 (Spain, 50 MW), PS20 solar power tower (Spain, 20 MW), and the PS10 solar power tower (Spain, 11 MW).

The solar thermal power industry is growing rapidly with 1.2 GW under construction as of April 2009 and another 13.9 GW announced globally through 2014. Spain is the epicenter of solar thermal power development with 22 projects for 1,037 MW under construction, all of which are projected to come online by the end of 2010.^[39] In the United States, 5,600 MW of solar thermal power projects have been announced.^[40] In developing countries, three World Bank projects for integrated solar thermal/combined-cycle gas-turbine power plants in Egypt, Mexico, and Morocco have been approved.^[41]

Photovoltaic market

40 MW PV Array installed in Waldpolenz, Germany

Photovoltaic production has been increasing by an average of some 20 percent each year since 2002, making it a fast-growing energy technology.^[42][6] At the end of 2009, the cumulative global PV installations surpassed 21,000 megawatts.^[6][7]

As of October 2009, the largest photovoltaic (PV) power plants in the world are the Olmedilla Photovoltaic Park (Spain, 60 MW), the Strasskirchen Solar Park (Germany, 54 MW), the Lieberose Photovoltaic Park (Germany, 53 MW), the Puertollano Photovoltaic Park (Spain, 50 MW), the Moura photovoltaic power station (Portugal, 46 MW), and the Waldpolenz Solar Park (Germany, 40 MW).^[43]

Many of these plants are integrated with agriculture and some use innovative tracking systems that follow the sun's daily path across the sky to generate more electricity than conventional fixed-mounted systems. There are no fuel costs or emissions during operation of the power stations.

Topaz Solar Farm is a proposed 550 MW solar photovoltaic power plant which is to be built northwest of California Valley in the USA at a cost of over $1 billion.^[44] High Plains Ranch is a proposed 250 MW solar photovoltaic power plant which is to be built on the Carrizo Plain, northwest of California Valley.^[45]

However, when it comes to renewable energy systems and PV, it is not just large systems that matter. Building-integrated photovoltaics or "onsite" PV systems have the advantage of being matched to end use energy needs in terms of scale. So the energy is supplied close to where it is needed.^[46]

Use of ethanol for transportation

E95 trial bus operating in São Paulo, Brazil.

Since the 1970s, Brazil has had an ethanol fuel program which has allowed the country to become the world's second largest producer of ethanol (after the United States) and the world's largest exporter.^[47] Brazil’s ethanol fuel program uses modern equipment and cheap sugar cane as feedstock, and the residual cane-waste (bagasse) is used to process heat and power.^[48] There are no longer light vehicles in Brazil running on pure gasoline. By the end of 2008 there were 35,000 filling stations throughout Brazil with at least one ethanol pump.^[49]

Nearly all the gasoline sold in the United States today is mixed with 10 percent ethanol, a mix known as E10,^[50] and motor vehicle manufacturers already produce vehicles designed to run on much higher ethanol blends. Ford, DaimlerChrysler, and GM are among the automobile companies that sell “flexible-fuel” cars, trucks, and minivans that can use gasoline and ethanol blends ranging from pure gasoline up to 85% ethanol (E85). By mid-2006, there were approximately six million E85-compatible vehicles on U.S. roads.^[51] The challenge is to expand the market for biofuels beyond the farm states where they have been most popular to date. Flex-fuel vehicles are assisting in this transition because they allow drivers to choose different fuels based on price and availability. The Energy Policy Act of 2005, which calls for 7.5 billion gallons of biofuels to be used annually by 2012, will also help to expand the market.^[51]

Geothermal energy commercialization

The West Ford Flat power plant is one of 21 power plants at The Geysers.

The International Geothermal Association (IGA) has reported that 10,715 megawatts (MW) of geothermal power in 24 countries is online, which is expected to generate 67,246 GWh of electricity in 2010.^[52] This represents a 20% increase in geothermal power online capacity since 2005. IGA projects this will grow to 18,500 MW by 2015, due to the large number of projects presently under consideration, often in areas previously assumed to have little exploitable resource.^[52]

In 2010, the United States led the world in geothermal electricity production with 3,086 MW of installed capacity from 77 power plants;^[53] the largest group of geothermal power plants in the world is located at The Geysers, a geothermal field in California.^[54] The Philippines follows the US as the second highest producer of geothermal power in the world, with 1,904 MW of capacity online; geothermal power makes up approximately 18% of the country's electricity generation.^[53]

Geothermal (ground source) heat pumps represented an estimated 30 GWth of installed capacity at the end of 2008, with other direct uses of geothermal heat (i.e., for space heating, agricultural drying and other uses) reaching an estimated 15 GWth. As of 2008, at least 76 countries use direct geothermal energy in some form.

Wave farms expansion

One of 3 Pelamis Wave Energy Converters in the harbor of Peniche, Portugal

Portugal now has the world's first commercial wave farm, the Agucadoura Wave Park, officially opened in September 2008. The farm uses three Pelamis P-750 machines generating 2.25 MW.^[55][56] Initial costs are put at € 8.5 million. A second phase of the project is now planned to increase the installed capacity to 21MW using a further 25 Pelamis machines.^[57]

Funding for a wave farm in Scotland was announced in February, 2007 by the Scottish Government, at a cost of over 4 million pounds, as part of a UK£13 million funding packages for ocean power in Scotland. The farm will be the world's largest with a capacity of 3MW generated by four Pelamis machines.^[58]

Developing country markets

Renewable energy can be particularly suitable for developing countries. In rural and remote areas, transmission and distribution of energy generated from fossil fuels can be difficult and expensive. Producing renewable energy locally can offer a viable alternative.^[59]

Biomass cookstoves are used by 40 percent of the world’s population. These stoves are being manufactured in factories and workshops worldwide, and more than 160 million households now use them.^[13] More than 30 million rural households get lighting and cooking from biogas made in household-scale digesters. An estimated 3 million households get power from small solar PV systems. Micro-hydro systems configured into village-scale or county-scale mini-grids serve many areas.^[13]

Kenya is the world leader in the number of solar power systems installed per capita. More than 30,000 very small solar panels, each producing 12 to 30 watts, are sold in Kenya annually.^[60]

Renewable energy projects in many developing countries have demonstrated that renewable energy can directly contribute to poverty alleviation by providing the energy needed for creating businesses and employment. Renewable energy technologies can also make indirect contributions to alleviating poverty by providing energy for cooking, space heating, and lighting. Renewable energy can also contribute to education, by providing electricity to schools.^[61]

Industry and policy trends

Global renewable energy investment growth (1995-2007)^[62]

Global revenues for solar photovoltaics, wind power, and biofuels expanded from $76 billion in 2007 to $115 billion in 2008. New global investments in clean energy technologies expanded by 4.7 percent from $148 billion in 2007 to $155 billion in 2008.^[15] U.S. President Barack Obama's American Recovery and Reinvestment Act of 2009 includes more than $70 billion in direct spending and tax credits for clean energy and associated transportation programs. Clean Edge suggests that the commercialization of clean energy will help countries around the world pull out of the current economic malaise.^[15] Leading renewable energy companies include First Solar, Gamesa, GE Energy, Q-Cells, Sharp Solar, Siemens, SunOpta, Suntech, and Vestas.^[63]

The International Renewable Energy Agency (IRENA) is an intergovernmental organization for promoting the adoption of renewable energy worldwide. It aims to provide concrete policy advice and facilitate capacity building and technology transfer. IRENA was formed on January 26, 2009, by 75 countries signing the charter of IRENA.^[64] As of March 2010, IRENA has 143 member states who all are considered as founding members, of which 14 have also ratified the statute.^[65]

Renewable energy policy targets exist in some 73 countries around the world, and public policies to promote renewable energy use have become more common in recent years. At least 64 countries have some type of policy to promote renewable power generation. Mandates for solar hot water in new construction are becoming more common at both national and local levels. Mandates for blending biofuels into vehicle fuels have been enacted in 17 countries.^[66]

New and emerging renewable energy technologies

New and emerging renewable energy technologies are still under development and include cellulosic ethanol, hot-dry-rock geothermal power, and ocean energy.^[67] These technologies are not yet widely demonstrated or have limited commercialization. Many are on the horizon and may have potential comparable to other renewable energy technologies, but still depend on attracting sufficient attention and research, development and demonstration (RD&D) funding.^[67]

Cellulosic ethanol

Companies such as Iogen, Broin, and Abengoa are building refineries that can process biomass and turn it into ethanol, while companies such as Diversa, Novozymes, and Dyadic are producing enzymes which could enable a cellulosic ethanol future. The shift from food crop feedstocks to waste residues and native grasses offers significant opportunities for a range of players, from farmers to biotechnology firms, and from project developers to investors.^[68]

Ocean energy

Systems to harvest utility-scale electrical power from ocean waves have recently been gaining momentum as a viable technology. The potential for this technology is considered promising, especially on west-facing coasts with latitudes between 40 and 60 degrees:^[72]

In the United Kingdom, for example, the Carbon Trust recently estimated the extent of the economically viable offshore resource at 55 TWh per year, about 14% of current national demand. Across Europe, the technologically achievable resource has been estimated to be at least 280 TWh per year. In 2003, the U.S. Electric Power Research Institute (EPRI) estimated the viable resource in the United States at 255 TWh per year (6% of demand).^[72]

The world's first commercial tidal power station was installed in 2007 in the narrows of Strangford Lough in Ireland. The 1.2 megawatt underwater tidal electricity generator, part of Northern Ireland's Environment & Renewable Energy Fund scheme, takes advantage of the fast tidal flow (up to 4 metres per second) in the lough. Although the generator is powerful enough to power a thousand homes, the turbine has minimal environmental impact, as it is almost entirely submerged, and the rotors pose no danger to wildlife as they turn quite slowly.^[73]

Ocean thermal energy conversion (OTEC) uses the temperature difference that exists between deep and shallow waters to run a heat engine.

Enhanced Geothermal Systems

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

Enhanced Geothermal Systems are a new type of geothermal power technologies that do not require natural convective hydrothermal resources. The vast majority of geothermal energy within drilling reach is in dry and non-porous rock.^[74] EGS technologies "enhance" and/or create geothermal resources in this "hot dry rock (HDR)" through hydraulic stimulation.

EGS / HDR technologies, like hydrothermal geothermal, are expected to be baseload resources which produce power 24 hours a day like a fossil plant. Distinct from hydrothermal, HDR / EGS may be feasible anywhere in the world, depending on the economic limits of drill depth. Good locations are over deep granite covered by a thick (3–5 km) layer of insulating sediments which slow heat loss.^[75] HDR wells are expected to have a useful life of 20 to 30 years before the outflow temperature drops about 10 degrees Celsius and the well becomes uneconomic. If left for 50 to 300 years the temperature will recover.^{[citation needed]}

There are HDR and EGS systems currently being developed and tested in France, Australia, Japan, Germany, the U.S. and Switzerland. The largest EGS project in the world is a 25 megawatt demonstration plant currently being developed in the Cooper Basin, Australia. The Cooper Basin has the potential to generate 5,000–10,000 MW.

Nanotechnology thin-film solar panels

Solar power panels that use nanotechnology, which can create circuits out of individual silicon molecules, may cost half as much as traditional photovoltaic cells, according to executives and investors involved in developing the products. Nanosolar has secured more than $100 million from investors to build a factory for nanotechnology thin-film solar panels.

Other

Osmotic power (or salinity gradient power) is the energy retrieved from the difference in the salt concentration between seawater and river water. Two practical methods for this are reverse electrodialysis^[76] (RED) and pressure retarded osmosis.^[77] (PRO).

A microbial fuel cell is a bio-electrochemical system that drives a current by mimicking bacterial interactions found in nature - converting chemical energy to electrical energy by the catalytic reaction of microorganisms.

Renewable energy debate

Renewable electricity production, from sources such as wind power and solar power, is sometimes criticized for being variable or intermittent. However, the International Energy Agency has stated that deployment of renewable technologies usually increases the diversity of electricity sources and, through local generation, contributes to the flexibility of the system and its resistance to central shocks.^[67]

There have been "not in my back yard" (NIMBY) concerns relating to the visual and other impacts of some wind farms, with local residents sometimes fighting or blocking construction.^[78] In the USA, the Massachusetts Cape Wind project was delayed for years partly because of aesthetic concerns. However, residents in other areas have been more positive and there are many examples of community wind farm developments. According to a town councilor, the overwhelming majority of locals believe that the Ardrossan Wind Farm in Scotland has enhanced the area.^[79]

See also

	Renewable energy portal
	Energy portal
	Sustainable development portal

Wikimedia Commons has media related to: Renewable energy

Wikinews has news related to: Renewable energy

Look up renewable energy in Wiktionary, the free dictionary.

Lists

• List of offshore wind farms
• List of onshore wind farms
• List of photovoltaics companies
• List of photovoltaic power stations
• List of renewable energy companies by stock exchange
• List of renewable energy organizations
• List of renewable energy technologies
• List of renewable energy topics by country
• List of solar thermal power stations
• List of wind turbine manufacturers
• List of countries by electricity production from renewable sources
• List of books about energy issues

Topics

Books

• Alternative Energy: Political, Economic, and Social Feasibility
• The Clean Tech Revolution
• Energy and American Society: Thirteen Myths
• Energy Autonomy: The Economic, Social & Technological Case for Renewable Energy
• Greenhouse Solutions with Sustainable Energy
• Non-Nuclear Futures: The Case for an Ethical Energy Strategy
• Outlook On Renewable Energy In America
• Renewable Electricity and the Grid
• Renewable Energy Sources and Climate Change Mitigation
• Small is Profitable: The Hidden Economic Benefits of Making Electrical Resources the Right Size
• Solar Electricity Handbook
• Ten Technologies to Fix Energy and Climate

References

Bibliography

• Aitken, Donald W. (2010). Transitioning to a Renewable Energy Future, International Solar Energy Society, January, 54 pages.
• HM Treasury (2006). Stern Review on the Economics of Climate Change, 575 pages.
• International Council for Science (c2006). Discussion Paper by the Scientific and Technological Community for the 14th session of the United Nations Commission on Sustainable Development, 17 pages.
• International Energy Agency (2006). World Energy Outlook 2006: Summary and Conclusions, OECD, 11 pages.
• International Energy Agency (2007). Renewables in global energy supply: An IEA facts sheet, OECD, 34 pages.
• International Energy Agency (2008). Deploying Renewables: Principles for Effective Policies, OECD, 8 pages.
• Makower, Joel, and Ron Pernick and Clint Wilder (2009). Clean Energy Trends 2009, Clean Edge.
• National Renewable Energy Laboratory (2006). Non-technical Barriers to Solar Energy Use: Review of Recent Literature, Technical Report, NREL/TP-520-40116, September, 30 pages.
• REN21 (2008). Renewables 2007 Global Status Report, Paris: REN21 Secretariat, 51 pages.
• REN21 (2009). Renewables Global Status Report: 2009 Update, Paris: REN21 Secretariat.
• REN21 (2010). Renewables 2010 Global Status Report, Paris: REN21 Secretariat, 78 pages.
• United Nations Environment Programme and New Energy Finance Ltd. (2007). Global Trends in Sustainable Energy Investment 2007: Analysis of Trends and Issues in the Financing of Renewable Energy and Energy Efficiency in OECD and Developing Countries, 52 pages.
• Worldwatch Institute and Center for American Progress (2006). American energy: The renewable path to energy security, 40 pages.