Renewable energy

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Renewable energy comes from renewable resources.^[1] It is different from fossil fuels as it does not produce as many greenhouse gases and other pollutants as fossil fuel combustion.

There are a lot of traditional uses of wind, water, and solar energy in developed and developing countries. But the mass production of electricity using renewable energy sources has become more common only recently. The reason for this are the major threats of climate change due to pollution, exhaustion of fossil fuels, and the environmental, social and political risks of fossil fuels and nuclear power.

1 Renewable energy use
2 Wind power market grows
3 World's largest PV power plants
4 New generation of solar thermal plants
5 Ethanol for transportation
6 See also
7 References
8 Other websites

[change] Renewable energy use

Renewable energy comes from natural sources like sunlight, wind, tides and geothermal heat. Each of these sources has qualities which influence how and where they are used.

Energy sources

Most renewable energy technologies are directly or indirectly powered by the Sun. The Earth-Atmosphere system is in equilibrium. That means that heat radiation into space is equal to incoming solar radiation. Therefore the level of energy within the Earth-Atmosphere system is more or less the same. One can describe it as the Earth's "climate."

Most radiation is absorbed by water, especially at the regions around the equator. But this energy is dissipated around the globe in the form of winds and ocean currents. A lot of energy is transferred from the atmosphere to the ocean through wind stress ^[2] and the reason, why wave motion plays an important role in gaining wave power. Solar energy is also responsible for the distribution of precipitation which is tapped by hydroelectric projects, and for the growth of plants used to create biofuels.

[change] Wind power market grows

Wind power: worldwide installed capacity and prediction 1997-2010, Source: WWEA

At the end of 2006, the total installed wind power capacity around the world was 74,223 megawatts (MW), up from 59,091 MW in 2005.^[3] The countries with the highest total installed capacity are Germany (20,621 MW), Spain (11,615 MW), the USA (11,603 MW), India (6,270 MW) and Denmark (3,136).^[4]

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 2006 reaching €18 billion, or US$23 billion.^[5]

[change] World's largest PV power plants

A big photovoltaic (PV) power project has been built in Portugal, in one of the Europe's sunniest areas.^[6] The 11 megawatt (MW) plant covers 150 acres and is has 52,000 PV panels. The panels are raised 2 metres off the ground and the area will remain productive grazing land. The project will provide enough energy for 8,000 homes and will save an estimated 30,000 tonnes of carbon dioxide emissions per year.^[7]^[8]

Construction of a 40 MW solar generation power plant is underway in Germany. The Waldpolenz Solar Park will consist of some 550,000 thin-film solar modules. The direct current produced in the modules will be converted into alternating current and fed completely into the power grid. Once completed in 2009, the project will be one of the largest photovoltaic projects ever constructed.^[9]

A $420 million large-scale Solar power station in Victoria is to be the biggest and most efficient solar photovoltaic power station in the world. Australian company Solar Systems will demonstrate its unique, world leading design incorporating space technology in a 154 MW solar power station connected to the national grid. The power station will have the capability to concentrate the sun by 500 times onto the solar cells for very high power output. The Victorian power station will generate clean electricity directly from the sun to meet the annual needs of over 45,000 homes with zero greenhouse gas emissions.^[10]

However, when it comes to renewable energy and PV, it is not just big 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.^[11]

[change] New generation of solar thermal plants

Main article: List of Solar thermal power stations

The 11 megawatt PS10 solar power tower in Spain produces electricity from the sun using 624 large movable mirrors called heliostats.

Construction of the largest solar thermal power plant to be built in 15 years, in Boulder City, Nevada, is nearly complete. The 64MW Nevada Solar One power plant will generate enough power to meet the electricity needs of about 40,000 households and follows in the steps of the 354MW SEGS solar thermal power plants located in California’s Mojave Desert. While California’s solar plants have generated billions of kilowatt hours of electricity for the past two decades, the Nevada Solar One plant will use new technologies to capture even more energy from the sun.^[12]

[change] Ethanol for transportation

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 percent of the country's automotive fuel. As a result, Brazil, which years ago had to import a large share of the petroleum needed for domestic consumption, recently reached complete self-sufficiency in oil.^[13]

Most cars on the road today in the U.S. can run on blends of up to 10% ethanol, 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.^[14]