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None World electricity generation by source in 2017. Total generation was 26 PWh. Renewable energy is energy that is collected from renewable resources, which are naturally replenished on a human timescale, including carbon neutral sources like sunlight, wind, rain, tides, waves, and geothermal heat. The term often also encompasses biomass as well, whose carbon neutral status is under debate. Renewable energy often provides energy in four important areas: electricity generation, air and water heating/cooling, transportation, and rural (off-grid) energy services. Based on REN21's 2017 report, renewables contributed 19.3% to humans' global energy consumption and 24.5% to their generation of electricity in 2015 and 2016, respectively. This energy consumption is divided as 8.9% coming from traditional biomass, 4.2% as heat energy (modern biomass, geothermal and solar heat), 3.9% from hydroelectricity and the remaining 2.2% is electricity from wind, solar, geothermal, and other

Renewable energy flows involve natural phenomena such as sunlight, wind, tides, plant growth, and geothermal heat, as the International Energy Agency explains: Renewable energy is derived from natural processes that are replenished constantly. In its various forms, it derives directly from the sun, or from heat generated deep within the earth. Included in the definition is electricity and heat generated from solar, wind, ocean, hydropower, biomass, geothermal resources, and biofuels and hydrogen derived from renewable resources. Renewable energy resources and significant opportunities for energy efficiency exist over wide geographical areas, in contrast to other energy sources, which are concentrated in a limited number of countries. Rapid deployment of renewable energy and energy efficiency, and technological diversification of energy sources, would result in significant energy security and economic benefits. It would also reduce environmental pollution such as air pollution caused by

Prior to the development of coal in the mid 19th century, nearly all energy used was renewable. Almost without a doubt the oldest known use of renewable energy, in the form of traditional biomass to fuel fires, dates from more than a million years ago. Use of biomass for fire did not become commonplace until many hundreds of thousands of years later. Probably the second oldest usage of renewable energy is harnessing the wind in order to drive ships over water. This practice can be traced back some 7000 years, to ships in the Persian Gulf and on the Nile. From hot springs, geothermal energy has been used for bathing since Paleolithic times and for space heating since ancient Roman times. Moving into the time of recorded history, the primary sources of traditional renewable energy were human labor, animal power, water power, wind, in grain crushing windmills, and firewood, a traditional biomass. In the 1860s and 1870s there were already fears that civilization would run out of fossil fue

Wind power At the end of 2019, worldwide installed wind power capacity was 623 GW. Air flow can be used to run wind turbines. Modern utility-scale wind turbines range from around 600 kW to 9 MW of rated power. The power available from the wind is a function of the cube of the wind speed, so as wind speed increases, power output increases up to the maximum output for the particular turbine. Areas where winds are stronger and more constant, such as offshore and high-altitude sites, are preferred locations for wind farms. Typically, full load hours of wind turbines vary between 16 and 57 percent annually, but might be higher in particularly favorable offshore sites. Wind-generated electricity met nearly 4% of global electricity demand in 2015, with nearly 63 GW of new wind power capacity installed. Wind energy was the leading source of new capacity in Europe, the US and Canada, and the second largest in China. In Denmark, wind energy met more than 40% of its electricity demand while Irela

Renewable energy production from some sources such as wind and solar is more variable and more geographically spread than technology based on fossil fuels and nuclear. While integrating it into the wider energy system is feasible, it does lead to some additional challenges. In order for the energy system to remain stable, a set of measurements can be taken. Implementation of energy storage, using a wide variety of renewable energy technologies, and implementing a smart grid in which energy is automatically used at the moment it is produced can reduce risks and costs of renewable energy implementation. In some locations, individual households can opt to purchase renewable energy through a consumer green energy program. Electrical energy storage Electrical energy storage is a collection of methods used to store electrical energy. Electrical energy is stored during times when production (especially from intermittent sources such as wind power, tidal power, solar power) exceeds consumption

Renewable power has been more effective in creating jobs than coal or oil in the United States. In 2016, employment in the sector increased 6 percent in the United States, causing employment in the non-renewable energy sector to decrease 18 percent. Worldwide, renewables employ about 8.1 million as of 2016. Growth of renewables From the end of 2004, worldwide renewable energy capacity grew at rates of 10–60% annually for many technologies. In 2015 global investment in renewables rose 5% to $285.9 billion, breaking the previous record of $278.5 billion in 2011. 2015 was also the first year that saw renewables, excluding large hydro, account for the majority of all new power capacity (134 GW, making up 54% of the total). citation needed Of the renewables total, wind accounted for 72 GW and solar photovoltaics 56 GW; both record-breaking numbers and sharply up from 2014 figures (49 GW and 45 GW respectively). In financial terms, solar made up 56% of total new investment and wind accounte

Policies to support renewable energy have been vital in their expansion. Where Europe dominated in establishing energy policy in early 2000s, most countries around the world now have some form of energy policy. Policy trends The International Renewable Energy Agency (IRENA) is an intergovernmental organization for promoting the adoption of renewable energy worldwide. It aims to provide concrete policy advice and facilitate capacity building and technology transfer. IRENA was formed in 2009, by 75 countries signing the charter of IRENA. As of April 2019, IRENA has 160 member states. The then United Nations' Secretary-General Ban Ki-moon has said that renewable energy has the ability to lift the poorest nations to new levels of prosperity, and in September 2011 he launched the UN Sustainable Energy for All initiative to improve energy access, efficiency and the deployment of renewable energy. The 2015 Paris Agreement on climate change motivated many countries to develop or improve re

Other renewable energy technologies are still under development, and include cellulosic ethanol, hot-dry-rock geothermal power, and marine energy. These technologies are not yet widely demonstrated or have limited commercialization. Many are on the horizon and may have potential comparable to other renewable energy technologies, but still depend on attracting sufficient attention and research, development and demonstration (RD&D) funding. There are numerous organizations within the academic, federal, and commercial sectors conducting large scale advanced research in the field of renewable energy. This research spans several areas of focus across the renewable energy spectrum. Most of the research is targeted at improving efficiency and increasing overall energy yields. Multiple federally supported research organizations have focused on renewable energy in recent years. Two of the most prominent of these labs are Sandia National Laboratories and the National Renewable Energy Laborat

This section needs to be updated . Please update this article to reflect recent events or newly available information. ( March 2019 ) Renewable electricity production, from sources such as wind power and solar power, is variable which results in reduced capacity factor and require either energy storage of capacity equal to its total output, or base load power sources from non intermittent sources like hydropower, fossil fuels or nuclear power. Since renewable energy sources power density per land area is at best three orders of magnitude smaller than fossil or nuclear power, renewable power plants tends to occupy thousands of hectares causing environmental concerns and opposition from local residents, especially in densely populated countries. Solar power plants are competing with arable land and nature reserves, while on-shore wind farms face opposition due to aesthetic concerns and noise, which is impacting both humans and wildlife. In the United States, the Massachusetts Cape Wind

This section needs expansion . You can help by adding to it. ( March 2019 ) From around 2010 onwards, there was increasing discussion about the geopolitical impact of the growing use of renewable energy. It was argued that former fossil fuels exporters would experience a weakening of their position in international affairs, while countries with abundant renewable energy resources would be strengthened. Also countries rich in critical materials for renewable energy technologies were expected to rise in importance in international affairs. The GeGaLo index of geopolitical gains and losses assesses how the geopolitical position of 156 countries may change if the world fully transitions to renewable energy resources. Former fossil fuels exporters are expected to lose power, while the positions of former fossil fuel importers and countries rich in renewable energy resources is expected to strengthen.

This section needs expansion . You can help by adding to it. ( March 2019 ) The ability of biomass and biofuels to contribute to a reduction in CO 2 emissions is limited because both biomass and biofuels emit large amounts of air pollution when burned and in some cases compete with food supply. Furthermore, biomass and biofuels consume large amounts of water. Other renewable sources such as wind power, photovoltaics, and hydroelectricity have the advantage of being able to conserve water, lower pollution and reduce CO 2 emissions. The installations used to produce wind, solar and hydro power are an increasing threat to key conservation areas, with facilities built in areas set aside for nature conservation and other environmentally sensitive areas. They are often much larger than fossil fuel power plants, needing areas of land up to 10 times greater than coal or gas to produce equivalent energy amounts. More than 2000 renewable energy facilities are built, and more are under constr

Burbo, NW-England Sunrise at the Fenton Wind Farm in Minnesota, US The CSP-station Andasol in Andalusia, Spain Ivanpah solar plant in the Mojave Desert, California, United States Three Gorges Dam and Gezhouba Dam, China Shop selling PV panels in Ouagadougou, Burkina Faso Stump harvesting increases recovery of biomass from forests A small, roof-top mounted PV system in Bonn, Germany The community-owned Westmill Solar Park in South East England Komekurayama photovoltaic power station in Kofu, Japan Krafla, a geothermal power station in Iceland