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...)
Mandatory renewable energy targets are part of government legislated schemes which require electricity merchandisers to source-specific amounts of aggregate electricity sales from renewable energy sources according to a fixed time frame. The objective of these schemes is to promote renewable energy and decrease dependency on fossil fuels. If this results in an additional expenditure of electricity, the additional cost is distributed across most customers by increases in other tariffs. The cost of this measure is therefore not funded by the government budgets, except for costs of establishing and monitoring the scheme and any audit and enforcement actions. As the cost of renewable energy has become cheaper than other sources, meeting and exceeding a renewable energy target will also reduce the expenditure of electricity to consumers.
At least 67 countries have renewable energy policy targets of some kind. In Europe, 28 European Union members states and 8 Energy Community Contracting Parties have legally binding renewable energy targets. The EU baseline target is 20% by 2020, while the United States also has a national RET of 20%. Similarly, Canada has 9 provincial RETs but no national target for renewable energy (although it does have a 2030 non-emitting target and coal phase-out by 2030). Targets are typically for shares of electricity production, but some are defined as by primary energy supply, installed capacity, or otherwise. While some targets are based on 2010-2012 data, many are now for 2020, which bonds in with the IPCC suggested greenhouse gas emission cuts of 25 to 40% by Annex I countries by 2020, although some are for 2025. (Full article...)
"We need to push ourselves to make as many reductions as possible in our own energy use first.. and that takes time. But we must do this quickly.. the climate will not wait for us." -Rupert Murdoch
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 10Acceptance 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 11Electricity generation at Wairakei, New Zealand (from Geothermal energy)
Image 21Share of electricity production from wind, 2022 (from Wind power)
Image 22Merowe 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 23The Hoover Dam in the United States is a large conventional dammed-hydro facility, with an installed capacity of 2,080 MW. (from Hydroelectricity)
Image 32Cost development of solar PV modules per watt (from Solar energy)
Image 33The Warwick Castle water-powered generator house, used for the generation of electricity for the castle from 1894 until 1940 (from Hydroelectricity)
Image 34Global map of wind speed at 100 meters on land and around coasts. (from Wind power)
Image 36Seasonal 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 37Solar water heaters facing the Sun to maximize gain (from Solar energy)
Image 38Electricity production by source (from Wind power)
Image 39Typical components of a wind turbine (gearbox, rotor shaft and brake assembly) being lifted into position (from Wind power)
Image 40Share of electricity production from hydropower, 2022 (from Hydroelectricity)
Image 41Electricity generation at Ohaaki, New Zealand (from Geothermal energy)
Image 42Wind 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 43Distribution 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 44A 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 45Installed geothermal energy capacity, 2022 (from Geothermal energy)
Image 46Parabolic dish produces steam for cooking, in Auroville, India. (from Solar energy)
Image 55Concentrated 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 56Energy from wind, sunlight or other renewable energy is converted to potential energy for storage in devices such as electric batteries or higher-elevation water reservoirs. The stored potential energy is later converted to electricity that is added to the power grid, even when the original energy source is not available. (from Wind power)
Image 57Enhanced 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 58A panoramic view of the United Kingdom's Whitelee Wind Farm with Lochgoin Reservoir in the foreground. (from Wind power)
Image 59Yearly hydro generation by continent (from Hydroelectricity)
.jpg?lang=en)
![Image 55Concentrated 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?lang=en)
