Renewable energy sources are projected to account for more than one quarter of global electricity production by 2020. Power-technology.com profiles the top five renewable energy sources based on global installed power generation capacities as of 2013.
Hydropower is the most widely-used renewable power source, with the global hydroelectric installed capacity exceeding 1,000GW, accounting for over 16% of the world's net electricity production and more than 65% of the global power generation capacity from renewable sources.
The most common method of hydropower generation involves construction of dams on rivers and releasing water from the reservoir to drive turbines. Pumped-storage type plants represent another method of hydroelectricity generation.
China has the biggest hydroelectric generation capacity in the world and hosts the world's largest hydro power plant, the Three Gorges (22.5GW). The nation accounted for over 50% of the total hydroelectric capacity added in the world in 2012. Brazil, the United States, Canada and Russia also have some of the biggest hydropower installations in the world.
Hydropower projects have, however, become controversial during recent years due to the environmental and social impacts related to bio-diversity and human resettlement.
Wind is the second most widely used renewable source, as global wind power installed capacity exceeded 283GW in 2013. The annual growth rate of cumulative wind power capacity has averaged 25% during last five years making wind the fastest growing renewable power source, a trend projected to continue in the future.
China, with an installed capacity of more than 75GW, is the biggest wind power generator in the world and the United States ranks second with its installed wind power capacity exceeding 60GW at the beginning of 2013. Germany, Spain, India, the UK, Italy, France, Canada and Portugal are the other major wind power producing countries, which together with China and the US, account for more than 85% of total wind power producing capacity in the world.
The 1,020MW Alta Wind Energy Centre (AWEC) in California, US, currently ranks as the biggest onshore wind farm in the world. The 630MW London Array wind farm located off the coast of UK is the biggest offshore wind farm.
Global installed capacity of solar power is more than 100GW, which makes it the third biggest renewable power source, with photovoltaic (PV) technology the dominant source. The use of concentrating solar power (CSP) technology is also on the rise and global installed capacity stood at 2.5GW at the beginning of 2013.
Germany, Italy, China, the US and Japan possess the biggest solar PV capacity in the world, while Spain is home to more than 75% of the global CSP capacity.
The 354MW Solar Energy Generating Systems (SEGS) in the Mojave Desert of California, US, is currently the biggest operational solar power plant in the world and the Ivanpah Solar Electric Generating System (ISEGS) in California, US, will join it as the biggest CSP plants in the world when it becomes fully operational.
Bio-power is the fourth biggest renewable power source after hydro, wind and solar. The world's net electricity production capacity from bio-mass currently exceeds 83GW, while global bio-power generation increased from 313TWh in 2010 to more than 350TWh in 2013.
Modern biomass, especially bio-fuels and wood pellets, are increasingly being used for heat and power generation, alongside traditional biomass sources such as agricultural by-products.
The US, Brazil, China, Germany and Sweden are currently the leading bio-power generators while GDF SUEZ's 205MW Green Unit biomass plant at Polaniec, Poland, which opened in June 2013, is the world's biggest 100% bio-mass fuelled power plant. The 140MW Vaskiluodon Voima plant in Finland, also launched in 2013, is the biggest bio-gas plant in the world.
Installed power production capacity from geothermal sources exceeded 11.7GW as of 2013 making it the fifth biggest renewable source for electricity generation. The global annual geothermal electricity generation exceeded 72TWh in 2012.
Electricity generation accounts for about one third of the renewable energy provided by geothermal resources, while the remaining two-thirds are used for direct heat generation. The US, Philippines, Indonesia, Mexico and Italy constitute the top five geothermal power producers in the world.
The Geysers Geothermal Complex, located north of San Francisco in California, US, with 900MW of active production capacity, is the world's biggest geothermal power plant, followed by the 769MW Larderello Geothermal Complex in Italy.