Résumé
Low-head hydropower refers to the development of hydroelectric power where the head is typically less than 20 metres, although precise definitions vary. Head is the vertical height measured between the hydro intake water level and the water level at the point of discharge. Using only a low head drop in a river or tidal flows to create electricity may provide a renewable energy source that will have a minimal impact on the environment. Since the generated power (calculated the same as per general hydropower) is a function of the head these systems are typically classed as small-scale hydropower, which have an installed capacity of less than 5MW. Most current hydroelectric projects use a large hydraulic head to power turbines to generate electricity. The hydraulic head either occurs naturally, such as a waterfall, or is created by constructing a dam in a river valley, creating a reservoir. Using a controlled release of water from the reservoir drives the turbines. The costs and environmental impacts of constructing a dam can make traditional hydroelectric projects unpopular in some countries. From 2010 onwards new innovative ecologically friendly technologies have evolved and have become economically viable. Within low-head hydropower there are several of standard situations: Run-of-the-river: Low-head small hydropower can be produced from rivers, often described as run-of-river or run-of-the-river projects. Suitable locations include weirs, streams, locks, rivers and wastewater outfalls. Weirs are common in rivers across Europe, as well as rivers that are canalized or have groynes. Generating significant power from low-head locations using conventional technologies typically requires large volumes of water. Due to the low rotational speeds produced, gearboxes are required to efficiently drive generators, which can result in large and expensive equipment and civil infrastructure. Tidal power: In combination with a lagoon or barrage the tides can be used to create a head difference.
À propos de ce résultat
Cette page est générée automatiquement et peut contenir des informations qui ne sont pas correctes, complètes, à jour ou pertinentes par rapport à votre recherche. Il en va de même pour toutes les autres pages de ce site. Veillez à vérifier les informations auprès des sources officielles de l'EPFL.