Portal:Renewable energy

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Introduction

Renewable energy (or green energy, low-carbon energy) is energy from renewable natural resources that are replenished on a human timescale. Mainstream renewable energy options include solar energy, wind power, hydropower, bioenergy and geothermal power. Renewable energy installations can be large or small. They are suited for urban as well as rural areas. Renewable energy is often deployed together with further electrification. This has several benefits: electricity can move heat or objects efficiently, and is clean at the point of consumption. Variable renewable energy sources are those that are not dispatchable due to their fluctuating nature, such as wind power and solar power. In contrast, controllable renewable energy sources include dammed hydroelectricity, bioenergy, or geothermal power. Using renewable energy and energy efficiency technologies is resulting in more energy security, climate change mitigation, and economic benefits.

From 2011 to 2021, renewable energy grew from 20% to 28% of global electricity supply. Use of fossil energy shrank from 68% to 62%, and nuclear from 12% to 10%. The share of hydropower decreased from 16% to 15% while power from sun and wind increased from 2% to 10%. Biomass and geothermal energy grew from 2% to 3%.

Renewable energy systems are rapidly becoming more efficient and cheaper. As a result, their share of the global energy consumption is increasing. A large majority of worldwide newly installed electricity capacity is now renewable. In most countries, photovoltaic solar or onshore wind are the cheapest new-build electricity. Renewable energy can help reduce energy poverty in rural and remote areas of developing countries, where lack of energy access is often hindering economic development.

Many countries around the world already have renewable energy contributing more than 20% of their total energy supply. Some countries generate over half their electricity from renewables. A few countries generate all their electricity from renewable energy. National renewable energy markets are projected to continue to grow strongly in the 2020s and beyond. According to the IEA, to achieve net zero emissions by 2050, 90% of global electricity generation will need to be produced from renewable sources.

Renewable energy resources exist all over the world. This is in contrast to fossil fuels resources which are concentrated in a limited number of countries. However, the deployment of renewable energy is being hindered by massive fossil fuel subsidies. In 2022 the International Energy Agency requested all countries to reduce their policy, regulatory, permitting and financing obstacles for renewables. This would increase the chances of the world reaching net zero carbon emissions by 2050.

There are ongoing debates around the renewable energy topic. For example, whether nuclear power should be grouped under the renewable energy category or not. There are also debates around geopolitics, the metal and mineral extraction needed for solar panels and batteries, possible installations in conservation areas and the need to recycle solar panels. Although most renewable energy sources are sustainable, some are not. For example, some biomass sources are unsustainable at current rates of exploitation.

There are also other renewable energy technologies that are still under development, for example enhanced geothermal systems, concentrated solar power, cellulosic ethanol, and marine energy. (Full article...)

Summary of the main ethanol blends used around the world in 2013

Ethanol fuel is fuel containing ethyl alcohol, the same type of alcohol as found in alcoholic beverages. It is most often used as a motor fuel, mainly as a biofuel additive for gasoline.

Several common ethanol fuel mixtures are in use around the world. The use of pure hydrous or anhydrous ethanol in internal combustion engines (ICEs) is only possible if the engines are designed or modified for that purpose. Anhydrous ethanol can be blended with gasoline (petrol) for use in gasoline engines, but with high ethanol content only after engine modifications to meter increased fuel volume since pure ethanol contains only 2/3 the energy of an equivalent volume of pure gasoline. High percentage ethanol mixtures are used in some racing engine applications as the very high octane rating of ethanol is compatible with very high compression ratios.

The first production car running entirely on ethanol was the Fiat 147, introduced in 1978 in Brazil by Fiat. Ethanol is commonly made from biomass such as corn or sugarcane. World ethanol production for transport fuel tripled between 2000 and 2007 from 17×109 liters (4.5×10^9 U.S. gal; 3.7×10^9 imp gal) to more than 52×109 liters (14×10^9 U.S. gal; 11×10^9 imp gal). From 2007 to 2008, the share of ethanol in global gasoline type fuel use increased from 3.7% to 5.4%. In 2011 worldwide ethanol fuel production reached 8.46×109 liters (2.23×10^9 U.S. gal; 1.86×10^9 imp gal) with the United States of America and Brazil being the top producers, accounting for 62.2% and 25% of global production, respectively. US ethanol production reached 57.54×109 liters (15.20×10^9 U.S. gal; 12.66×10^9 imp gal) in May 2017. (Full article...)
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  • "Perhaps because of its technical, economic, and thermodynamic advantages, a renewable power sector would have six benefits over one reliant on conventional power plants, including (1) lower negative externalities per kWh, (2) more stable and predictable fuel prices, (3) fewer greenhouse gas emissions, (4) less water use, (5) improved efficiency, and (6) greater local employment and revenue." – Benjamin K. Sovacool and Charmaine Watts. The Electricity Journal, May 2009, Vol. 22, Issue 4, p. 99.
  • "... renewable electricity technologies present policy makers with a superior alternative for minimising the risk of fuel interruptions and shortages, helping improve the fragile transmission network and reducing environmental harm. These smaller and more environmentally friendly generators cost less to construct, produce power in smaller increments and need not rely on continuous government subsidies. They generate little to no waste, have less greenhouse gas emissions per unit of electricity produced and do not contribute significantly to the risk of accidents." – Benjamin K. Sovacool, Journal of Contemporary Asia, 40(3), 2010, p. 371.

Main topics

Renewable energy sources

General

Renewable energy commercialization · Smart grid · Timeline of sustainable energy research 2020–present

Renewable energy by country

List of countries by electricity production from renewable sources

WikiProjects

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View of a rapeseed field at Grendon, Northamptonshire
Rapeseed field at Grendon, Northamptonshire. Rapeseed oil is used in the manufacture of biodiesel for powering motor vehicles.

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Hermann Scheer (2008)

Hermann Scheer (29 April 1944 – 14 October 2010) was a Social Democrat member of the German Bundestag (parliament), President of Eurosolar (European Association for Renewable Energy) and General Chairman of the World Council for Renewable Energy. In 1999, Scheer was awarded the Right Livelihood Award for his "indefatigable work for the promotion of solar energy worldwide".

Scheer believed that the continuation of current patterns of energy supply and use would be environmentally, socially, economically, and politically damaging, with renewable energy being the only realistic alternative. Scheer had concluded that it is technically and environmentally feasible to harness enough solar radiation to achieve a total replacement of the foclear (fossil/nuclear) energy system by a global renewable energy economy. The main obstacle to such a change is seen to be political, not technical or economic. In 1999 he was one of the initiators of the German feed-in tariffs that were the major source of the rise of renewable energies in Germany during the following years. (Full article...)

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... that the United Nations Intergovernmental Panel on Climate Change (IPCC) published Renewable Energy Sources and Climate Change Mitigation (SRREN) in May 2011 ? The IPCC examined renewable energy and energy efficiency in its fourth assessment report, published in 2007, but members have now decided that renewable energy commercialization merits in-depth coverage because of its importance in reducing carbon emissions.

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The following are images from various renewable energy-related articles on Wikipedia.

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