Renewable energy capacity additions in 2020 expanded by more than 45% from 2019, including 90% more new wind power
(green) and a 23% expansion of new solar photovoltaic
is energy that is collected from renewable resources
that are naturally replenished on a human timescale
. It includes sources such as sunlight
, the movement of water
, and geothermal heat
. Although most renewable energy sources are sustainable
, some are not. For example, some biomass
sources are considered unsustainable at current rates of exploitation
. Renewable energy often provides energy for electricity generation
to a grid, air
and water heating
, and stand-alone power systems
From 2011 to 2021, renewable energy has grown from 20% to 28% of global electricity supply. Fossil energy shrunk 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.
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. Studies have shown that a global transition to 100% renewable energy across all sectors – power, heat, transport and desalination – 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. But the International Energy Agency said in 2021 that to reach net zero carbon emissions more effort is needed to increase renewables, and called for generation to increase by about 12% a year to 2030.
Renewable energy technology projects are typically large-scale, but they are also suited to rural and remote areas and developing countries, where energy is often crucial in human development. As most of the renewable energy technologies provide electricity, renewable energy is often deployed together with further electrification, which has several benefits: electricity can move heat or objects efficiently, and is clean at the point of consumption. In addition, electrification with renewable energy is more efficient and therefore leads to significant reductions in primary energy requirements. In 2021, China accounted for almost half of the global increase in renewable electricity. (Full article...)
Selected article -
The dam in September 2009
The Three Gorges Dam is a hydroelectric gravity dam that spans the Yangtze River by the town of Sandouping, in Yiling District, Yichang, Hubei province, central China, downstream of the Three Gorges. The Three Gorges Dam has been the world's largest power station in terms of installed capacity (22,500 MW) since 2012. The dam generates an average 95±20 TWh of electricity per year, depending on annual amount of precipitation in the river basin. After the extensive monsoon rainfalls of 2020, the dam's annual production nearly reached 112 TWh, breaking the previous world record of ~103 TWh set by Itaipu Dam in 2016.
The dam body was completed in 2006. The power plant of the dam project was completed and fully functional as of July 4, 2012, when the last of the main water turbines in the underground plant began production. Each main water turbine has a capacity of 700 MW. Coupling the dam's 32 main turbines with two smaller generators (50 MW each) to power the plant itself, the total electric generating capacity of the dam is 22,500 MW. The last major component of the project, the ship lift, was completed in December 2015.
As well as producing electricity
, the dam is intended to increase the Yangtze River's shipping capacity. By providing flood storage space, the dam reduces the potential for floods downstream which have historically plagued the Yangtze Plain
. In 1931, floods
on the river caused the deaths of up to 4 million people. As a result, China regards the project as a monumental social and economical success, with the design of state-of-the-art large turbines, and a move toward limiting greenhouse gas emissions
. However, the dam has caused ecological
changes including an increased risk of landslides
. Because of that, the dam has been controversial both domestically and abroad. (Full article...
- "The sunlight ... that strikes Earth’s land surface in two hours is equivalent to total human energy use in a year. While much of that sunlight becomes heat, solar energy is also responsible for the energy embodied in wind, hydro, wave, and biomass, each with the potential to be harnessed for human use. Only a small portion of that enormous daily, renewable flux of energy will ever be needed by humanity."
- "Improved energy productivity and renewable energy are both available in abundance—and new policies and technologies are rapidly making them more economically competitive with fossil fuels. In combination, these energy options represent the most robust alternative to the current energy system, capable of providing the diverse array of energy services that a modern economy requires. Given the urgency of the climate problem, that is indeed convenient."
– Christopher Flavin in Worldwatch Institute (2008). Building a Low-Carbon Economy in State of the World 2008, p. 80.
Selected image -
, an oil windmill
built in 1672 and still in operation, located in Zaanstad, Netherlands.
Selected biography -
Did you know? -
... 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.
General images -
The following are images from various renewable energy-related articles on Wikipedia.
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)
A turbine blade convoy passing through
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. (from Solar energy)
Concentrated solar panels are getting a power boost.
Distribution 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
Merowe 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)
Trends in the top five hydroelectricity-producing countries (from
Greenhouses like these in the Westland municipality of the Netherlands grow vegetables, fruits and flowers. (from Solar energy)
Global geothermal electric capacity. Upper red line is installed capacity; lower green line is realized production. (from
Electricity production by source (from
Typical components of a wind turbine (gearbox, rotor shaft and brake assembly) being lifted into position (from
Typical wind turbine components:
Wind energy generation by region over time (from
Cumbria, England, have been opposed for a number of reasons, including aesthetics, by some sectors of the population. (from Wind power)
Wind turbines such as these, in
Seasonal 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
Onshore wind cost per kilowatt-hour between 1983 and 2017 (from
Cost development of solar PV modules per watt (from
Hoover Dam in the United States is a large conventional dammed-hydro facility, with an installed capacity of 2,080 MW. (from Hydroelectricity)
Global map of wind speed at 100 m above surface level. (from
Enhanced 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)
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