page_title: Sustainable energy
section_title: Hydropower
hierarchical_section_title: Sustainable energy / Renewable energy sources / Hydropower
caption_attribution_description: English: Nishidaira Dam.日本語: 西平ダム。
context_page_description: Sustainable energy is the practice of using energy in a way that "meets the needs of the present without compromising the ability of future generations to meet their own needs."
  The energy transition to meet the world's needs for electricity, heating, cooling, and power for transport in a sustainable way is widely considered to be one of the greatest challenges facing humanity in the 21st century. Worldwide, nearly a billion people lack access to electricity, and around 3 billion people rely on smoky fuels such as wood, charcoal or animal dung in order to cook. These and fossil fuels are a major contributor to air pollution, which causes an estimated 7 million deaths per year. Production and consumption of energy emits over 70% of human-caused greenhouse gas emissions.
  Proposed pathways for limiting global warming to 1.5 °C describe rapid implementation of low-emission methods of producing electricity and a shift towards more use of electricity in sectors such as transport. The pathways also include measures to reduce energy consumption; and use of carbon-neutral fuels, such as hydrogen produced by renewable electricity or with carbon capture and storage.
context_section_description: Among sources of renewable energy, hydroelectric plants have the advantages of being long-lived—many existing plants have operated for more than 100 years. Also, hydroelectric plants are clean, have few emissions and can compensate for variations in wind and solar power. Criticisms directed at large-scale hydroelectric plants include: dislocation of people living where the reservoirs are planned, and release of greenhouse gases during construction and flooding of the reservoir.
  However, it has been found that high emissions are associated only with shallow reservoirs in warm (tropical) locales, and recent innovations in hydropower turbine technology are enabling efficient development of low-impact run-of-the-river hydroelectricity projects. Generally speaking, hydroelectric plants produce much lower life-cycle emissions than other types of generation.
  In 2015, hydropower supplied 16% of the world's electricity, down from a high of nearly 20% in the mid-to late 20th century. It produced 60% of electricity in Canada and nearly 80% in Brazil. As of 2017, new hydropower construction has stopped or slowed down since 1980 in most countries except China.
caption: Hydroelectric dams are one of the most widely deployed sources of sustainable energy.
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