In 2021, hydropower generated 15% of the global electricity supply, third only to coal and gas, and more than all other renewable sources combined.
Share of hydro in global electricity (%)
Biggest source of renewable electricity - for now
Output has steadily grown for the past 20 years, although faster growth in wind and solar is closing the gap. Ember’s Global Electricity Review revealed hydro electricity had a 2% fall in production in 2021, due to low rainfall in key countries such as China, Brazil, the US and Türkiye.
China produces 31% of global hydropower, more than triple the next largest producer, Brazil. These two countries have also dominated recent growth in capacity. More than 30 countries produce the majority of their electricity from hydro sources.
Hydropower – with its ability to supply power on demand – has an important role to play in enabling high penetration of variable renewable sources. Both expansion and modernisation of capacities will be required as part of the solution to replace fossil fuels. This must be done in a way that minimises lifecycle project greenhouse gas emissions, and accounts for socioeconomic and biodiversity impacts, which have historically been undervalued.
Last updated: Nov 2022
The world's biggest hydro generators
A low emissions, flexible power source with an important enabling role to play
Hydropower will soon lose its status as the top renewable power source, as wind and solar are faster and cheaper to deploy. It will however grow in importance as a valuable source of balancing on daily to seasonal timescales in fossil-free power systems.
The IEA Net Zero scenario requires hydropower output to continue growing at approximately 3% annually until 2030. This would require capacity growth averaging 48 GW per year: over twice that of recent years. Even the IEA’s most optimistic forecast sees hydro falling 45% short of the 1.5C aligned pathway. Investments in refurbishments are also lagging behind.
Opportunity beckons for hydropower: less than half of the global economic potential has been tapped, and pumped hydro storage remains the cheapest form of much-needed electricity storage. Moreover, covering only 10% of reservoirs with new floating solar technology could more than double output from hydroelectric dams.
Yet challenges to development are complex. New reservoirs can become significant sources of emissions. A changing climate will impact operations, demonstrated by record low water levels at California’s Hoover dam. Large dams have already negatively affected an estimated half a billion people, and a trend towards larger dams in biologically important river basins in Africa, South East Asia, and Latin America, hastens the need for robust standards. Addressing the negative social and environmental impacts of hydro will be crucial for its future success.