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 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 renewables 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. For example, some biomass sources are unsustainable at current rates of exploitation. (Full article...)
Hydroelectricity, or hydroelectric power, is electricity generated from hydropower (water power). Hydropower supplies one sixth of the world's electricity, almost 4,500 TWh in 2020, which is more than all other renewable sources combined and also more than nuclear power. Hydropower can provide large amounts of low-carbon electricity on demand, making it a key element for creating secure and clean electricity supply systems. A hydroelectric power station that has a dam and reservoir is a flexible source, since the amount of electricity produced can be increased or decreased in seconds or minutes in response to varying electricity demand. Once a hydroelectric complex is constructed, it produces no direct waste, and almost always emits considerably less greenhouse gas than fossil fuel-powered energy plants. However, when constructed in lowland rainforest areas, where part of the forest is inundated, substantial amounts of greenhouse gases may be emitted.
Construction of a hydroelectric complex can have significant environmental impact, principally in loss of arable land and population displacement. They also disrupt the natural ecology of the river involved, affecting habitats and ecosystems, and siltation and erosion patterns. While dams can ameliorate the risks of flooding, dam failure can be catastrophic.
In 2021, global installed hydropower electrical capacity reached almost 1,400 GW, the highest among all renewable energy technologies. Hydroelectricity plays a leading role in countries like Brazil, Norway and China. but there are geographical limits and environmental issues. Tidal power can be used in coastal regions. (Full article...)
"Ethanol creates U.S. jobs, cleans the air, strengthens national security – and best of all, it is here right now. Every day, ethanol producers are developing technological improvements to increase efficiency, reduce water use, and boost the amount of energy derived from corn kernels or from cellulosic biomass. Ethanol is not a 'someday' fuel. It is the renewable, clean-burning alternative we have to gasoline today."
John Ingle Yellott (October 25, 1908 – December 30, 1986) was an American engineer recognized as a pioneer in passive solar energy, and an inventor with many patents to his credit. In his honor the American Society of Mechanical Engineers (ASME) Solar Division confers a biannual "John I. Yellott Award" which "recognizes ASME members who have demonstrated sustained leadership within the Solar Energy Division, have a reputation for performing high-quality solar energy research and have made significant contributions to solar engineering through education, state or federal government service or in the private sector." (Full article...)
Image 3Acceptance of wind and solar facilities in one's community is stronger among U.S. Democrats (blue), while acceptance of nuclear power plants is stronger among U.S. Republicans (red). (from Wind power)
Image 4Wind turbines such as these, in Cumbria, England, have been opposed for a number of reasons, including aesthetics, by some sectors of the population. (from Wind power)
Image 5Museum Hydroelectric power plant "Under the Town" in Užice, Serbia, built in 1900. (from Hydroelectricity)
Image 6Concentrated solar panels are getting a power boost. Pacific Northwest National Laboratory (PNNL) will be testing a new concentrated solar power system – one that can help natural gas power plants reduce their fuel usage by up to 20 percent.[needs update] (from Solar energy)
Image 9The Hoover Dam in the United States is a large conventional dammed-hydro facility, with an installed capacity of 2,080 MW. (from Hydroelectricity)
Image 10A turbine blade convoy passing through Edenfield in the U.K. (2008). Even longer 2-piece blades are now manufactured, and then assembled on-site to reduce difficulties in transportation. (from Wind power)
Image 11Electricity production by source (from Wind power)
Image 18Enhanced 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 (from Geothermal energy)
Image 28The oldest known pool fed by a hot spring, built in the Qin dynasty in the 3rd century BCE (from Geothermal energy)
Image 29Distribution 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. (from Wind power)
Image 30Krafla Geothermal Station in northeast Iceland (from Geothermal energy)
Image 31The Warwick Castle water-powered generator house, used for the generation of electricity for the castle from 1894 until 1940 (from Hydroelectricity)
Image 44Greenhouse gas emissions per energy source. Wind energy is one of the sources with the least greenhouse gas emissions. (from Wind power)
Image 45Solar water heaters facing the Sun to maximize gain (from Solar energy)
Image 46Seasonal cycle of capacity factors for wind and photovoltaics in Europe under idealized assumptions. The figure illustrates the balancing effects of wind and solar energy at the seasonal scale (Kaspar et al., 2019). (from Wind power)
Image 47Global geothermal electric capacity. Upper red line is installed capacity; lower green line is realized production. (from Geothermal energy)
Image 48Installed geothermal energy capacity, 2022 (from Geothermal energy)
Image 49Wind turbine floating off France (from Wind power)
Image 51Merowe Dam in Sudan. Hydroelectric power stations that use dams submerge large areas of land due to the requirement of a reservoir. These changes to land color or albedo, alongside certain projects that concurrently submerge rainforests, can in these specific cases result in the global warming impact, or equivalent life-cycle greenhouse gases of hydroelectricity projects, to potentially exceed that of coal power stations. (from Hydroelectricity)
Image 52Electricity generation at Wairakei, New Zealand (from Geothermal energy)
Image 53Greenhouses like these in the Westland municipality of the Netherlands grow vegetables, fruits and flowers. (from Solar energy)
Image 54A panoramic view of the United Kingdom's Whitelee Wind Farm with Lochgoin Reservoir in the foreground. (from Wind power)
Image 55Share of electricity production from wind, 2022 (from Wind power)
Image 56Parabolic dish produces steam for cooking, in Auroville, India. (from Solar energy)
Image 57Onshore wind cost per kilowatt-hour between 1983 and 2017 (from Wind power)
Image 58Global map of wind speed at 100 meters on land and around coasts. (from Wind power)
Image 59Global map of wind power density potential (from Wind power)
![Image 6Concentrated solar panels are getting a power boost. Pacific Northwest National Laboratory (PNNL) will be testing a new concentrated solar power system – one that can help natural gas power plants reduce their fuel usage by up to 20 percent.[needs update] (from Solar energy)](/wiki/File:Photo_of_the_Week-_Boosting_Solar_Technology_(8722948189).jpg)
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