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Introduction

Wind, solar, and hydroelectricity are three emerging 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. 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. As of 2015 worldwide, more than half 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

View of the Three Gorges Dam on the Yangtze River, China

The Three Gorges Dam is a hydroelectric dam that spans the Yangtze River by the town of Sandouping, located in the Yiling District of Yichang, in Hubei province, China. The Three Gorges Dam is the world’s largest capacity hydroelectric power station with a total generating capacity of 18,200 MW.

The dam body was completed in 2006. Except for a ship lift, the originally planned components of the project were completed on October 30, 2008, when the 26th turbine in the shore plant began commercial operation. Each turbine has a capacity of 700  MW. Six additional turbines in the underground power plant are not expected to become fully operational until 2012. Coupling the dam's thirty-two main turbines with two smaller generators (50 MW each) to power the plant itself, the total electric generating capacity of the dam will eventually reach 22,500 MW.

As well as producing electricity, the dam increases the Yangtze River's shipping capacity, and reduces the potential for floods downstream by providing flood storage space. The Chinese government regards the project as a historic engineering, social and economic success, with the design of state-of-the-art large turbines, and a move toward limiting greenhouse gas emissions. However, the dam flooded archaeological and cultural sites and displaced some 1.3 million people, and is causing significant ecological changes, including an increased risk of landslides. The dam has been a controversial topic both in China and abroad.

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Barack Obama speaks at Nellis AFB 2009-05-27 2.jpg
President Barack Obama addressed an audience of more than 450 people at the Nellis Solar Power Plant on May 27, 2009.

Selected biography

Hans-Josef Fell1.JPG

Hans-Josef Fell (born 7 January 1952 in Hammelburg) is a member of the Green Party in the German Parliament. Fell framed the German Renewable Energy legislation, together with Hermann Scheer. He currently serves as spokesman on energy for the Alliance 90/The Greens parliamentary group.

Fell has travelled to many countries to discuss clean energy. Following his visit to Turkey, plans for a nuclear power plant at Akkuyu were stopped, and Prime Minister Bülent Ecevit declared that his government would foster renewable technologies. In Taiwan, following Fell's television appearances and talks with individual policy makers, the government announced the withdrawal of its plans to build the country's fourth nuclear power plant, and its intent to phase out nuclear power by 2020. The French government has also shown great interest in drafting a renewable energy law similar to the one in Germany.

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Did you know?

... that The Clean Tech Revolution: The Next Big Growth and Investment Opportunity, the 2007 book by Ron Pernick and Clint Wilder, argues that commercializing clean technologies is a profitable enterprise that is moving steadily into mainstream business ? As the world economy faces challenges from energy price spikes, resource shortages, global environmental problems, and security threats, clean technologies are seen to be the next engine of economic growth.

Pernick and Wilder highlight eight major clean technology sectors: solar power, wind power, biofuels, green buildings, personal transportation, the smart grid, mobile applications (such as portable fuel cells), and water filtration. Very large corporations such as GE, Toyota and Sharp, and investment firms such as Goldman Sachs are making multi-billion dollar investments in clean technology.

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  • "Wind projects boost local tax bases, helping to pay for schools, roads and hospitals. Wind projects also revitalize the economy of rural communities by providing steady income to farmers and other landowners. Each wind turbine contributes $3,000 to $5,000 or more per year in rental income, while farmers continue to grow crops or graze cattle up to the foot of the turbines." – American Wind Energy Association (2009). Annual Wind Industry Report, Year Ending 2008 pp. 9–10.
  • "A wind farm, when installed on agricultural land, has one of the lowest environmental impacts of all energy sources. It occupies less land area per kilowatt-hour (kWh) of electricity generated than any other energy conversion system, apart from rooftop solar energy, and is compatible with grazing and crops." – Mark Diesendorf, in Dissent, No. 13, Summer 2003/04, pp. 43–48.

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