Pumped storage hydropower
The world's water batteries
Pumped storage hydropower is the world's largest battery technology, accounting for over 94 per cent of installed energy storage capacity, well ahead of lithium-ion and other battery types.
IHA estimates that pumped storage hydropower (PSH) projects now store up to 9,000 gigawatt hours (GWh) of electricity globally.
The technology is an ideal complement to modern clean energy systems, as pumped storage can accommodate for the intermittency and seasonality of variable renewables such as wind and solar power.
Figure: Pumped storage hydropower plant with upper and lower reservoirs
Flexible and versatile
The flexibility pumped storage hydropower (PSH) provides through its storage and ancillary grid services is increasingly important in securing stable power supplies.
PSH provides flexibility through system inertia, frequency control, voltage regulation, storage and reserve power with rapid mode changes, and black-start capability. All of these are vital to support the ever-growing proportion of variable renewable energy (VRE) in grid systems.
Pumped storage particularly excels at its long discharge duration and highpower capacity that will be crucial in avoiding VRE curtailment, reducing transmission congestion, and reducing overall costs and emissions in the power sector.
In addition, PSH enjoys several distinct advantages over other forms of energy storage due to its long asset life, low-lifetime cost and independence from raw material availability.
According to IHA's Hydropower Status Report, total installed pumped storage hydropower capacity was estimated at 158 GW in 2019.
Multiple studies have identified vast potential for pumped storage sites worldwide and there is growing research on possibilities for retrofitting disused mines, underground caverns, non-powered dams and conventional hydro plants.
As a result of a resurgence of interest in the technology, with more than 100 projects in the pipeline, IHA estimates that pumped hydropower storage capacity is expected to increase by almost 50 per cent – to about 240 GW by 2030.
Obstacles to pumped storage hydropower include existing market regulations and policy frameworks which fail to incentivise new developments.
The flexibility and storage services provided by PSH are not yet adequately valued, reducing private sector investment and holding back potential new projects.
Tracking new projects
IHA's Pumped Storage Tracking Tool maps the locations and vital statistics for existing and planned pumped storage projects. It is the most comprehensive online resource on the world's 'water batteries'.
The tool shows the status of a pumped storage project, its installed generating and pumping capacity, and its actual or planned date of commissioning.
Read IHA's working paper, The World’s Water Battery: Pumped Hydropower Storage and the Clean Energy Transition.
The paper shows that PHS needs to secure new sources of reliable and long term revenue to attract investment, particularly in liberalised energy markets.
Download the Hydropower Status Report for latest pumped storage statistics from IHA's hydropower database.