1 Jun 2023
Hydropower
Hydropower, or hydroelectricity, is expected to remain the world’s largest source of renewable electricity generation and play a critical role in decarbonising the power system and improving system flexibility.
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Hydropower is a mature technology, yet it continues to evolve. Reservoir hydropower plants and pumped storage plants are particularly suited to providing system flexibility, while run-of-the river hydropower plants are themselves variable according to current or seasonal weather conditions.
Run-of-river hydropower plants harness energy for electricity production mainly from the available flow of the river. These plants may include short-term storage or "pondage", allowing for some hourly or daily flexibility but they usually have substantial seasonal and yearly variations.
Reservoir hydropower plants rely on stored water in a reservoir. This provides the flexibility to generate electricity on demand and reduces dependence on the variability of inflows. Very large reservoirs can retain months or even years of average inflows and can also provide flood protection and irrigation services.
Pumped storage plants use water that is pumped from a lower reservoir into an upper reservoir when electricity supply exceeds demand or can be generated at low cost. When demand exceeds instantaneous electricity generation and electricity has a high value, water is released to flow back from the upper reservoir through turbines to generate electricity. Pumped storage currently represents the overwhelming majority of on-grid electricity storage.
Run-of-river hydropower plants harness energy for electricity production mainly from the available flow of the river. These plants may include short-term storage or "pondage", allowing for some hourly or daily flexibility but they usually have substantial seasonal and yearly variations.
Reservoir hydropower plants rely on stored water in a reservoir. This provides the flexibility to generate electricity on demand and reduces dependence on the variability of inflows. Very large reservoirs can retain months or even years of average inflows and can also provide flood protection and irrigation services.
Pumped storage plants use water that is pumped from a lower reservoir into an upper reservoir when electricity supply exceeds demand or can be generated at low cost. When demand exceeds instantaneous electricity generation and electricity has a high value, water is released to flow back from the upper reservoir through turbines to generate electricity. Pumped storage currently represents the overwhelming majority of on-grid electricity storage.
Last updated Dec 12, 2022
Key findings
Hydropower generation in the Net Zero Scenario, 2010-2030
OpenDue to droughts, hydropower generation decreased in 2021 for the first time in two decades, despite relatively high capacity growth
In 2021 global hydropower generation decreased by 15 TWh (down 0.4%) to 4 327 TWh. The drop in generation was caused by persistent droughts in hydropower-rich countries. At the same time, capacity additions in 2021 reached 35 GW, 50% higher than the average of the previous five years. However, severe draughts continue in 2022, which can result in continuation of below average generation.
In the Net Zero Emissions by 2050 Scenario, hydropower maintains an average annual generation growth rate of about 3% in 2022-2030 to provide approximately 5 700 TWh of electricity per year. In the last five years the growth rate was just one-third of what is required, signalling a need for significantly stronger efforts, especially to streamline permitting and ensure project sustainability.
In the Net Zero Emissions by 2050 Scenario, hydropower maintains an average annual generation growth rate of about 3% in 2022-2030 to provide approximately 5 700 TWh of electricity per year. In the last five years the growth rate was just one-third of what is required, signalling a need for significantly stronger efforts, especially to streamline permitting and ensure project sustainability.
Global net hydropower capacity additions by region, 1991-2030
OpenWithout major policy changes, global hydropower expansion is expected to slow down this decade
Global hydropower capacity is set to increase by 17%, or 230 GW, between 2021 and 2030. However, net capacity additions over this period are forecast to decrease by 23% compared with the previous decade. The contraction results from slowdowns in the development of projects in China, Latin America and Europe. However, increasing growth in Asia Pacific, Africa and the Middle East partly offsets these declines.
The IEA is providing the world’s first detailed forecasts to 2030 for three types of hydropower: reservoir, run-of-river and pumped storage plants. Reservoir hydropower plants account for half of net hydropower additions through 2030 in our forecast. Pumped storage hydropower plants represent 30% of net hydropower additions through 2030 in our forecast. Run-of-river hydropower remains the smallest growth segment because it includes many small-scale projects below 10 MW.
The IEA is providing the world’s first detailed forecasts to 2030 for three types of hydropower: reservoir, run-of-river and pumped storage plants. Reservoir hydropower plants account for half of net hydropower additions through 2030 in our forecast. Pumped storage hydropower plants represent 30% of net hydropower additions through 2030 in our forecast. Run-of-river hydropower remains the smallest growth segment because it includes many small-scale projects below 10 MW.
Share of cumulative power capacity by technology, 2010-2027
OpenSolar PV claims the most installed power capacity worldwide by 2027, surpassing coal, natural gas and hydropower
Cumulative PV capacity almost triples to over 2 350 GW by 2027 in the main case, surpassing hydropower in 2024, natural gas in 2026 and coal in 2027 to become the largest installed electricity capacity worldwide. Hydropower is falling to third place in terms of installed renewable capacity due to the rapid expansion of wind.
Overall renewable electricity generation is expected to increase almost 60% to reach over 12 400 TWh, with hydropower remaining the primary source of renewable electricity generation throughout the forecast period even though its capacity expands less than that of wind and solar PV.
Overall renewable electricity generation is expected to increase almost 60% to reach over 12 400 TWh, with hydropower remaining the primary source of renewable electricity generation throughout the forecast period even though its capacity expands less than that of wind and solar PV.
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Our work on Hydropower
Hydropwer is the largest source of renewable electricity in the world and it is particularly suited to providing system flexibility. The Hydropower TCP is a global platform for advancing hydropower technology, encouraging the sustainable use of water resources for the development and management of hydropower.
Related sectoral Technology Collaboration Programmes (TCP)
Events
15 Dec 2022 15:00—16:00
Renewables 2022: Key findings
15 Nov 2022 12:30—14:00
IEA at COP27: The role of hydropower in achieving climate resilience
25 Mar 2022 09:00—16:00
