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Introduction

Wind, solar, and hydroelectricity are three renewable sources of energy.

Renewable energy is energy that is collected from renewable resources, which are naturally replenished on a human timescale, such as sunlight, wind, rain, tides, waves, and geothermal heat. 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 forms of biomass. Worldwide investments in renewable technologies amounted to more than US$286 billion in 2015. In 2017, worldwide investments in renewable energy amounted to US$279.8 billion, with China accounting for US$126.6 billion or 45% of the global investments, the United States for US$40.5 billion, and Europe for US$40.9 billion. Globally, there are an estimated 7.7 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. worldwide, more than two-thirds of all new electricity capacity installed was renewable. Growth in consumption of coal and oil could end by 2020 due to increased uptake of renewables and natural gas.

At the national level, at least 30 nations around the world already have renewable energy contributing more than 20 percent of energy supply. National renewable energy markets are projected to continue to grow strongly in the coming decade and beyond. Some places and at least two countries, Iceland and Norway, generate all their electricity using renewable energy already, and many other countries have the set a goal to reach 100% renewable energy in the future. At least 47 nations around the world already have over 50 percent of electricity from renewable resources. Renewable energy resources exist over wide geographical areas, in contrast to fossil fuels, which are concentrated in a limited number of countries. Rapid deployment of renewable energy and energy efficiency technologies is resulting in significant energy security, climate change mitigation, and economic benefits. In international public opinion surveys there is strong support for promoting renewable sources such as solar power and wind power.

While many renewable energy projects are large-scale, renewable technologies are also suited to rural and remote areas and developing countries, where energy is often crucial in human development. As most of renewable energy technologies provide electricity, renewable energy deployment is often applied in conjunction with further electrification, which has several benefits: electricity can be converted to heat (where necessary generating higher temperatures than fossil fuels), can be converted into mechanical energy with high efficiency, 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.

Selected article

The West Ford Flat power plant is one of 22 power plants at The Geysers

The Geysers is the world's largest geothermal field, containing a complex of 22 geothermal power plants, drawing steam from more than 350 wells, located in the Mayacamas Mountains approximately 72 miles (116 km) north of San Francisco, California. Read more...

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Alt=SeaGen tidal power plant, Strangford, County Down, Northern Ireland
SeaGen tidal power plant, Strangford, Northern Ireland.

Selected biography

Denis hayes 1980.jpg

Denis Hayes (1944– ) is an environmental activist and proponent of solar power. He rose to prominence in 1970 as the coordinator for the first Earth Day. Hayes founded the Earth Day Network and expanded it to more than 180 nations. During the Carter Administration, Hayes became head of the Solar Energy Research Institute (now known as the National Renewable Energy Laboratory), but left this position when the Reagan administration cut funding for the program. Since 1992, Hayes has been president of the Bullitt Foundation in Washington.

Hayes has received the national Jefferson Awards Medal for Outstanding Public Service as well as the highest awards bestowed by the Sierra Club, The Humane Society of the United States, the National Wildlife Federation, the Natural Resources Council of America, the Global Environmental Facility of the World Bank, the Interfaith Center on Corporate Responsibility, and the American Solar Energy Society. Time magazine named him as “Hero of the Planet” in 1999.

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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.

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  •  "Ethanol creates U.S. jobs, cleans the air, strengthens national security – and best of all, it is here right now. Every day, ethanol producers are developing technological improvements to increase efficiency, reduce water use, and boost the amount of energy derived from corn kernels or from cellulosic biomass. Ethanol is not a 'someday' fuel. It is the renewable, clean-burning alternative we have to gasoline today."
"Moreover, advancements in ethanol production are quickly opening the door for the commercialization of cellulosic ethanol and other advanced biofuels."

Ethanol is Here Today Renewable Energy World, 19 August 2010.

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