pumphüdroenergia

Pumped-hydro energy storage (PHES), also known as pumped-storage hydroelectricity, is a mature form of gravitational energy storage used for electric power system balancing. It stores energy by moving water between two reservoirs at different elevations, typically using surplus electricity to pump water uphill.

During periods of high electricity demand, water is released from the upper reservoir through turbines to generate electricity. The cycle is reversible, allowing PHES to charge and discharge as needed.

A PHES plant comprises upper and lower reservoirs, intake structures, penstocks, reversible pump-turbine units, a powerhouse, and associated electrical and control equipment that coordinate pumping and generation.

Round-trip efficiency commonly ranges around 70–85%, depending on design and operating conditions. PHES provides rapid response, strong ramping capability and the ability to store large amounts of energy for hours or days.

PHES is well suited for long-duration storage and grid stabilization, providing capacity from hundreds of megawatts to several gigawatts and energy storage from tens to thousands of megawatt-hours, complementing intermittent renewables.

Site selection requires an appropriate elevation difference and access to water resources, with considerations for land use, ecological impact, evaporation, and local communities. Environmental assessments and mitigation measures are typically part of project development.

PHES is among the most established large-scale energy storage technologies, with notable plants such as Dinorwig in the United Kingdom and Grand’Maison in France illustrating its scale and role in grid reliability.

Ongoing work focuses on improving efficiency, reducing pumping losses, and exploring new configurations such as underground or repurposed reservoirs and variable-speed machines. PHES is expected to remain a key tool for integrating renewable energy and maintaining grid stability.