Vannkraft

Vannkraft, commonly called hydropower, is energy generated from the movement or potential energy of water. It converts the gravitational energy of stored water or the kinetic energy of flowing water into electricity through turbines and generators, without direct combustion of fuels.

How it works: Water is stored in reservoirs or diverted from rivers to flow through turbines. The resulting mechanical energy drives generators that produce electricity, which is then transmitted to the power grid. Hydropower plants vary by design: dam-based plants with large reservoirs, run-of-river installations with minimal storage, and pumped-storage plants that move water uphill during periods of low demand to release later for peaking power. Small-scale or micro-hydro facilities serve individual communities or remote locations.

History and role: Hydropower has long been a cornerstone of electricity generation in many countries. It played a central role in industrialization in parts of Europe and North America, and remains a dominant source of renewable electricity in regions with abundant water resources and favorable topography, such as Norway.

Environmental and social aspects: Large hydro can alter river ecosystems, affect fish migration and sediment transport, and require resettlement. Mitigation approaches include fish passage facilities, environmentally conscious site selection, sediment management, and flow regulation to balance ecology with energy needs.

Economics and system role: Hydropower offers low operating costs, high reliability, and fast response to changes in demand. Its capability as a flexible and dispatchable resource supports grid stability and storage, particularly in pumped-storage schemes, complementing other renewable sources.