Government of Ireland

Long Duration Energy Storage refers to technologies that can store energy for many hours, days, or even seasons, going beyond the few hours typically provided by lithium‑ion batteries.[9] Hydrogen‑based LDES uses green hydrogen as the storage medium, enabling large‑scale, long‑term storage of energy that can support high shares of variable renewables in the power system.[6][9]

Green hydrogen production in this context refers to generating hydrogen via water electrolysis powered by renewable electricity, such as wind or solar, so that the resulting hydrogen has very low lifecycle greenhouse gas emissions.[6] In the Rathrush project, surplus renewable electricity that would otherwise be curtailed is intended to drive electrolysers that split water into hydrogen and oxygen, with the hydrogen stored for later use in electricity generation.

Hydrogen produced from renewable electricity sources, considered a critical component for hydrogen's long-term credibility as a clean fuel.

Ireland

Birmingham

Portugal

A proposed 600 MW long‑duration energy storage project in County Carlow, Ireland, using surplus renewable electricity to produce green hydrogen, store it underground in lined rock caverns, and reconvert it into electricity for the national grid.