Renewable energy
Hydropower
Definition
Hydropower is electricity produced by using the energy of flowing or stored water to drive turbines, in run-of-river, reservoir, pumped-storage, or offshore configurations. It is the largest source of renewable electricity globally — over half of all renewable generation and roughly 14 per cent of total electricity — and supplies nearly a third of the world's flexible electricity capacity, making it a key complement to variable solar and wind.
References
scale and system role
definition
Overview
What it means
Hydropower's value to the energy transition is not only kilowatt-hours but flexibility: reservoirs and pumped storage balance grids as renewables grow.
Its sustainability, however, is contested: large dams fragment rivers, disrupt fish migration and sediment flows, can emit reservoir methane, and have displaced communities — which is why dedicated sustainability assessment tools exist and why new projects face far stricter scrutiny than the fleet built in the twentieth century.
How it is used
The term anchors energy statistics, renewable-energy targets, and debates over dam standards, river basin management, and climate-resilient water storage.
Why it matters
The energy transition needs both clean energy and grid flexibility; hydropower supplies both — at ecological prices that must be honestly managed. **Note:** 1395 Hydropower sustainability merges into this entry; assessment tools such as the Hydropower Sustainability Assessment Protocol are covered here.