Renewable energy is energy which comes from natural resources such as sunlight, wind, rain, tides, and geothermal heat, which are renewable (naturally replenished). About 16% of global final energy consumption comes from renewables, with 10% coming from traditional biomass, which is mainly used for heating, and 3.4% from hydroelectricity. New renewables (small hydro, modern biomass, wind, solar, geothermal, and biofuels) accounted for another 2.8% and are growing rapidly.
Wind power is growing at the rate of 30% annually, with a worldwide installed capacity of 282,482 megawatts (MW) at the end of 2012, and is widely used in Europe, Asia, and the United States. At the end of 2013 the photovoltaic (PV) capacity worldwide was 136,000 MW, and PV power stations are popular in Germany and Italy and growing rapidly in China. Solar thermal power stations operate in the USA and Spain, and the largest of these is the 354 MW SEGS power plant in the Mojave Desert. The world's largest geothermal power installation is The Geysers in California, with a rated capacity of 750 MW. Brazil has one of the largest renewable energy programs in the world, involving production of ethanol fuel from sugar cane, and ethanol now provides 18% of the country's automotive fuel. Ethanol fuel is also widely available in the USA.
While many renewable energy projects are large-scale, renewable technologies are also suited to rural and remote areas, where energy is often crucial in human development. As of 2011, small solar PV systems provide electricity to a few million households, and micro-hydro configured into mini-grids serves many more. Over 44 million households use biogas made in household-scale digesters for lighting and/or cooking, and more than 166 million households rely on a new generation of more-efficient biomass cookstoves. United Nation's Secretary-General Ban Ki-moon has said that renewable energy has the ability to lift the poorest nations to new levels of prosperity.
Climate change concerns, coupled with high oil prices, peak oil, and increasing government support, are driving increasing renewable energy legislation, incentives and commercialization. New government spending, regulation and policies helped the industry weather the global financial crisis better than many other sectors. According to a 2011 projection by the International Energy Agency, solar power generators may produce most of the world’s electricity within 50 years.
Hydroelectricity is electricity generated by hydropower, i.e., the production of electrical power through the use of the gravitational force of falling or flowing water. It is the most widely used form of renewable energy. Once a hydroelectric complex is constructed, the project produces no direct waste, and has a considerably lower output level of the greenhouse gas carbon dioxide (CO2) than fossil fuel powered energy plants. Worldwide, an installed capacity of 777 GWe supplied 2998 TWh of hydroelectricity in 2006. This was approximately 20% of the world's electricity, and accounted for about 88% of electricity from renewable sources.
Most hydroelectric power comes from the potential energy of dammed water driving a water turbine and generator. In this case the energy extracted from the water depends on the volume and on the difference in height between the source and the water's outflow. This height difference is called the head. The amount of potential energy in water is proportional to the head. To obtain very high head, water for a hydraulic turbine may be run through a large pipe called a penstock.
... that the International Renewable Energy Agency (IRENA) to promote widespread and increased adoption and sustainable use of all forms or renewable energy was founded in 2009 ? Acting as the global voice for renewable energies, IRENA will facilitate access to all relevant renewable energy information.
IRENA's founding reflects a growing consensus among governments around the world on the need to speed up the commercialization of renewable energy worldwide. IRENA provides advice and support to governments on renewable energy policy, capacity building, and technology transfer. IRENA will also co-ordinate with existing renewable energy organizations, such as REN21.
- April 13, 2014: According to the UN's Fifth IPCC Report the most realistic option for the future is to triple the use of renewable energy. (The Guardian)
- April 10, 2014: IKEA buys 98-MW Hoopeston wind farm to achieve its goal of producing more renewable energy than it consumes by 2020. (REW)
- March 28, 2014: Renewable electricity in the UK rose by 28% in 2013. (REW)
- February 25, 2014: 64% of Australians support the renewable energy target despite government review. (The Guardian)
- February 12, 2014: Ivanpah Solar Power Facility -the World's largest- opens in California. (The Independent)
- February 11, 2014: Billionaire Donald Trump loses legal case against wind farm near his golf field. (The Guardian)
- February 6, 2014: The European Parliament votes for a renewable energy target of 30% by 2030. (The Guardian)
- January 30, 2014: China sets world record with 12GW of new solar power installed in 2013. (The Guardian)
- January 22, 2014: The European Commission agrees on a renewable energy target of 27% by 2030. (Press Release)
- January 7, 2014: Ministers from eight countries including France and Germany call for a EU-wide 2030 renewable energy target. (The Guardian)
- "First, once the renewable infrastructure is built, the fuel is free forever. Unlike carbon-based fuels, the wind and the sun and the earth itself provide fuel that is free, in amounts that are effectively limitless."
- "Second, while fossil fuel technologies are more mature, renewable energy technologies are being rapidly improved. So innovation and ingenuity give us the ability to constantly increase the efficiency of renewable energy and continually reduce its cost."
- "Third, once the world makes a clear commitment to shifting toward renewable energy, the volume of production will itself sharply reduce the cost of each windmill and each solar panel, while adding yet more incentives for additional research and development to further speed up the innovation process."
– Al Gore, Our Choice, 2009, p. 58.