Portal:Renewable energy

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Introduction

Renewable energy (or green energy) is energy from renewable natural resources that are replenished on a human timescale. The most widely used renewable energy types are solar energy, wind power, and hydropower. Bioenergy and geothermal power are also significant in some countries. Some also consider nuclear power a renewable power source, although this is controversial. Renewable energy installations can be large or small and are suited for both urban and rural areas. Renewable energy is often deployed together with further electrification. This has several benefits: electricity can move heat and vehicles efficiently and is clean at the point of consumption. Variable renewable energy sources are those that have a fluctuating nature, such as wind power and solar power. In contrast, controllable renewable energy sources include dammed hydroelectricity, bioenergy, or geothermal power.

Renewable energy systems have rapidly become more efficient and cheaper over the past 30 years. A large majority of worldwide newly installed electricity capacity is now renewable. Renewable energy sources, such as solar and wind power, have seen significant cost reductions over the past decade, making them more competitive with traditional fossil fuels. In most countries, photovoltaic solar or onshore wind are the cheapest new-build electricity. From 2011 to 2021, renewable energy grew from 20% to 28% of global electricity supply. Power from the sun and wind accounted for most of this increase, growing from a combined 2% to 10%. Use of fossil energy shrank from 68% to 62%. In 2022, renewables accounted for 30% of global electricity generation and are projected to reach over 42% by 2028. Many countries already have renewables contributing more than 20% of their total energy supply, with some generating over half or even all their electricity from renewable sources.

The main motivation to replace fossil fuels with renewable energy sources is to slow and eventually stop climate change, which is widely agreed to be caused mostly by greenhouse gas emissions. In general, renewable energy sources cause much lower emissions than fossil fuels. The International Energy Agency estimates that to achieve net zero emissions by 2050, 90% of global electricity generation will need to be produced from renewable sources. Renewables also cause much less air pollution than fossil fuels, improving public health, and are less noisy.

The deployment of renewable energy still faces obstacles, especially fossil fuel subsidies, lobbying by incumbent power providers, and local opposition to the use of land for renewable installations. Like all mining, the extraction of minerals required for many renewable energy technologies also results in environmental damage. In addition, although most renewable energy sources are sustainable, some are not. (Full article...)

An areal view of a large circle of thousands of bluish mirrors in a tan desert
A solar power tower at Crescent Dunes Solar Energy Project concentrating light via 10,000 mirrored heliostats spanning thirteen million sq ft (1.21 km2).

Concentrated solar power (CSP, also known as concentrating solar power, concentrated solar thermal) systems generate solar power by using mirrors or lenses to concentrate a large area of sunlight into a receiver. Electricity is generated when the concentrated light is converted to heat (solar thermal energy), which drives a heat engine (usually a steam turbine) connected to an electrical power generator or powers a thermochemical reaction.

As of 2021, global installed capacity of concentrated solar power stood at 6.8 GW. As of 2023, the total was 8.1 GW, with the inclusion of three new CSP projects in construction in China and in Dubai in the UAE. The U.S.-based National Renewable Energy Laboratory (NREL), which maintains a global database of CSP plants, counts 6.6 GW of operational capacity and another 1.5 GW under construction. (Full article...)

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  • "Perhaps the quickest, easiest, and most profitable way to reduce electricity use worldwide — thus cutting carbon emissions — is simply to change light bulbs. Replacing the inefficient incandescent light bulbs that are still widely used today with new compact fluorescents (CFLs) can reduce electricity use by three fourths. The energy saved by replacing a 100-watt incandescent bulb with an equivalent CFL over its lifetime is sufficient to drive a Toyota Prius hybrid car from New York to San Francisco."
  • "Over its lifetime, each standard (13 watt) CFL will reduce electricity bills by roughly $30. And though a CFL may cost twice as much as an incandescent, it lasts 10 times as long. Since it uses less energy, it also means fewer CO2 emissions. Each one reduces energy use by the equivalent of 200 pounds of coal over its lifetime."

Lester R. Brown. PLAN B 3.0: Mobilizing to Save Civilization 2008, p. 215.

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

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Solar cookers use sunlight as energy source for outdoor cooking.

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Chu in 2014

Steven Chu FREng ForMemRS HonFInstP (born February 28, 1948) is an American physicist and former government official. He is a Nobel laureate and was the 12th U.S. secretary of energy. He is currently the William R. Kenan Jr. Professor of Physics and Professor of Molecular and Cellular Physiology at Stanford University. He is known for his research at the University of California, Berkeley, and his research at Bell Laboratories and Stanford University regarding the cooling and trapping of atoms with laser light, for which he shared the 1997 Nobel Prize in Physics with Claude Cohen-Tannoudji and William Daniel Phillips.[ambiguous]

Chu served as U.S. Secretary of Energy under the administration of President Barack Obama from 2009 to 2013. At the time of his appointment as Energy Secretary, Chu was a professor of physics and molecular and cellular biology at the University of California, Berkeley, and the director of the Lawrence Berkeley National Laboratory, where his research was concerned primarily with the study of biological systems at the single molecule level. Chu resigned as energy secretary on April 22, 2013. He returned to Stanford as Professor of Physics and Professor of Molecular & Cellular Physiology. (Full article...)

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... that the Ontario Sustainable Energy Association (OSEA) is a non-profit organization supporting the growth of renewable energy and Community Power projects in the Canadian Province of Ontario? OSEA advocated an advanced renewable energy Feed-in Tariff program for Ontario, resulting in the creation of the Renewable Energy Standard Offer Program, a precursor to the Green Energy Act and, in 2007, the most progressive energy policy in North America in a decade. OSEA has approximately 130 community and industry members as well as individual members.

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

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