Electricity storage

🔋 Electricity storage

With ever more solar and wind power, the electricity system needs to store the surplus energy produced when the sun shines or the wind blows and return it when they do not. In Spain today this is done mainly by pumped-storage plants (which pump water up to an upper reservoir and run it through turbines later), and batteries are starting to arrive.

How much energy is stored

The latest year is incomplete. Storage is a net consumer: for every 100 kWh used to pump water, about 64 are recovered (2025). It pays off because water is pumped when electricity is plentiful and cheap (at midday, with solar) and run through the turbines when it is scarce and expensive. Pumped-storage generation has more than doubled since 2021 (from 2.6 to 5.9 TWh in 2025): there are more and more hours of solar surplus to make use of.

Batteries

Batteries are still small compared with pumped storage (in 2025 they moved about 800 times less energy), but installed capacity is growing and there are thousands of megawatts with grid access permits. REE only publishes separate figures for batteries hybridised with renewable plants; standalone batteries (connected to the grid on their own) and those used for self-consumption in homes and businesses have no open official statistics.

The last year, day by day

Records since daily data became available (late 2024): 4,632 MW pumping simultaneously (30/05/2026) and 3,051 MW generating (07/04/2026). March to May, with plenty of sun and water, is when most pumping takes place. Real-time ESIOS data (may differ slightly from the final balance).

Where it is

An access permit reserves capacity at a substation on REE's transmission grid; it does not mean that the project has been built or that it will be. Projects connected to the distribution grid are not included. Spain's National Integrated Energy and Climate Plan (PNIEC 2023-2030) envisages 22.5 GW of storage by 2030.

Sources and notes

• REE – Electricity balance (REData): pumped-storage generation and consumption, battery discharge and charge, monthly since 2015. This is the official figure.
• REE – ESIOS: indicators 2066/2065 (pumped storage) and 2198/2199 (batteries) in real time, and installed capacity of pure pumped storage (1476) and hybridised batteries (2275) by region.
• REE – Access capacity of the transmission grid: capacity granted and being processed for storage by node; SpainFacts keeps a snapshot of each monthly file.
• MITECO – PNIEC 2023-2030: storage target.
• Pure pumped-storage capacity does not include mixed pumped-storage plants (which also receive natural inflows from a river), which ESIOS does not break down: total pumped-storage capacity is higher.

Data updated 7 minutes ago