Grid-Scale Energy Storage is Already Revealing its Infirmity

It’s assumptions all the way down, while gas is the reality.

Conceptual decarbonisation of large electrical grids mostly with a mix of solar and wind induces the need of third factor to account for times of low generation, so that supply can meet demand. Thus,

❝Grid-scale batteries… are considered critical to the world’s transition away from burning fossil fuels because of their ability to soak up surplus renewable power in the daytime and use it to plug gaps and stabilise the grid once the sun sets or during other periods of low wind and sunlight.❞

This need is so fundamental that batteries are all but considered a renewable energy technology.

In 2024, the solar+wind share of the EU’s electricity supply was almost 30%. A report this month from “EU watchdog” the Agency for the Cooperation of Energy Regulators (ACER) outlines how the expansion of renewable share has reduced coal and gas generation in general, but not at times of high demand.

But, from page 37:

Emerging flexibility solutions

Interconnectivity, storage, and demand-side flexibility are becoming essential for stabilizing markets and preventing excessively low capture prices* for wind and solar, in addition to facilitating grid operation. Expanding and diversifying flexibility resources, including large-scale batteries, will reduce reliance on fossil fuels.

And Europe’s total battery energy storage capacity was 58.3 GWh in 2024.

Except, what’s that in the slide up there, on the right-hand-side, squeezed between Gas and Coal?

Hydro Pumped Storage.

In 2024 the EU’s total pumped hydro capacity was estimated at about 45 GW for power output and 1,270 GWh for energy storage (in contrast to the 58.3 for batteries).

1,270 ÷ 58.3 ≈ 22

i.e. the EU already has about 22 times the energy storage capacity in pumped hydro compared to its “critical to the world’s transition away from burning fossil fuels” batteries.

Hopefully, the same question is now occurring to everyone:

If expanding large-scale batteries is expected to “reduce reliance on fossil fuels”, why isn’t pumped hydro already achieving that when it dwarfs battery capacity today?

Hopefully, both proponents of battery storage, and of pumped hydro, who assume their preferred technology will simply “plug gaps once the sun sets or during other periods of low wind and sunlight” can stop, and honestly reflect on this question.

(* The capture price is the weighted average price that a power generation technology receives for its electricity in the market.)

Oscar Archer holds a PhD in chemistry and has been analysing energy issues for twenty years, focusing on nuclear technology since 2014, with a background in manufacturing and QA. Sometimes he helps out at WePlanet Australia. Find him @OskaArcher on Twitter.