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%. There are 3,146 gigawatts installed in 135 countries, while 156 countries have laws regulating the renewable energy sector. In 2021, China accounted for almost half of the global increase in renewable electricity.
Globally there are over 10 million jobs associated with the renewable energy industries, with solar photovoltaics being the largest renewable employer. Renewable energy systems are rapidly becoming more efficient and cheaper and their share of total energy consumption is increasing, with a large majority of worldwide newly installed electricity capacity being renewable. In most countries, photovoltaic solar or onshore wind are the cheapest new-build electricity.
Many nations around the world already have renewable energy contributing more than 20% of their total energy supply, with some generating over half their electricity from renewables. A few countries generate all their electricity using 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. Some studies have shown that a global transition to 100% renewable energy across all sectors – power, heat, transport and industry – is feasible and economically viable. Renewable energy resources exist over wide geographical areas, in contrast to fossil fuels, which are concentrated in a limited number of countries. Deployment of renewable energy and energy efficiency technologies is resulting in significant energy security, climate change mitigation, and economic benefits. However renewables are being hindered by hundreds of billions of dollars of fossil fuel subsidies. In international public opinion surveys there is strong support for renewables such as solar power and wind power. In 2022 the International Energy Agency asked countries to solve policy, regulatory, permitting and financing obstacles to adding more renewables, to have a better chance of reaching net zero carbon emissions by 2050. (Full article...)
Research into this topic is fairly new, with very few studies published before 2009, but has gained increasing attention in recent years. The majority of studies show that a global transition to 100% renewable energy across all sectors – power, heat, transport and industry – is feasible and economically viable.[need quotation to verify] A cross-sectoral, holistic approach is seen as an important feature of 100% renewable energy systems and is based on the assumption "that the best solutions can be found only if one focuses on the synergies between the sectors" of the energy system such as electricity, heat, transport or industry.
"The sun provides more energy in one hour than all humanity uses, in all forms, in a single year. Sunlight can provide us with its own resolution to our energy problems. The only transformation required is for humanity to reduce, or end, consumption of stored solar (as fossil fuels) and, in its place, use freely available 'fresh' solar". – David S. Findley (2010). Solar power for your home, p.12.
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 2Seasonal 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 6Wind 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 7Electricity production by source (from Wind power)
Image 8Merowe 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 9Trends in the top five hydroelectricity-producing countries (from Hydroelectricity)
Image 10Greenhouses like these in the Westland municipality of the Netherlands grow vegetables, fruits and flowers. (from Solar energy)
Image 16Enhanced 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 20A 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 45Distribution 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 46Wind turbine floating off France (from Wind power)