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...)
Waves are generated primarily by wind passing over the sea's surface and also by tidal forces, temperature variations, and other factors. As long as the waves propagate slower than the wind speed just above, energy is transferred from the wind to the waves. Air pressure differences between the windward and leeward sides of a wave crest and surface friction from the wind cause shear stress and wave growth.
Wave power as a descriptive term is different from tidal power, which seeks to primarily capture the energy of the current caused by the gravitational pull of the Sun and Moon. However, wave power and tidal power are not fundamentally distinct and have significant cross-over in technology and implementation. Other forces can create currents, including breaking waves, wind, the Coriolis effect, cabbeling, and temperature and salinity differences. (Full article...)
"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.
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...)
... that the Exelon Pavilions, a set of four solar energy generating structures in Millennium Park of Chicago, provide sufficient energy to power the equivalent of 14 star-rated energy-efficient houses in Chicago ? In addition to producing energy, three of the four pavilions provide access to the park's below ground parking garages and the fourth serves as the park's welcoming center. Exelon, a company that generates the electricity transmitted by its subsidiary Commonwealth Edison, donated approximately $5–6 million for the Pavilions.
Image 3Seasonal 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 4Greenhouse gas emissions per energy source. Wind energy is one of the sources with the least greenhouse gas emissions. (from Wind power)
Image 5Acceptance 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 6Electricity generation at Ohaaki, New Zealand (from Geothermal energy)
Image 13Concentrated 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 16Global map of wind power density potential (from Wind power)
Image 17Enhanced 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 18Share of electricity production from hydropower, 2022 (from Hydroelectricity)
Image 20Museum Hydroelectric power plant "Under the Town" in Užice, Serbia, built in 1900. (from Hydroelectricity)
Image 21Distribution 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 22Krafla Geothermal Station in northeast Iceland (from Geothermal energy)
Image 23The oldest known pool fed by a hot spring, built in the Qin dynasty in the 3rd century BCE (from Geothermal energy)
Image 24Installed geothermal energy capacity, 2022 (from Geothermal energy)
Image 25The Warwick Castle water-powered generator house, used for the generation of electricity for the castle from 1894 until 1940 (from Hydroelectricity)
Image 26A 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 27Global geothermal electric capacity. Upper red line is installed capacity; lower green line is realized production. (from Geothermal energy)
Image 31Hydro generation by country, 2021 (from Hydroelectricity)
Image 32Electricity production by source (from Wind power)
Image 33Yearly hydro generation by continent (from Hydroelectricity)
Image 34Merowe 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 45Wind 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 46Greenhouses like these in the Westland municipality of the Netherlands grow vegetables, fruits and flowers. (from Solar energy)
Image 59The Hoover Dam in the United States is a large conventional dammed-hydro facility, with an installed capacity of 2,080 MW. (from Hydroelectricity)
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![Image 13Concentrated 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.php?slug=File:Photo_of_the_Week-_Boosting_Solar_Technology_(8722948189).jpg)
