Power Engineering Primer
Pumped Hydro and Hydrogen Storage Primer — Choosing Between Storage That Spans Hours and Storage That Spans Seasons
Lithium-ion batteries are strong at balancing supply and demand over minutes to a few hours, but filling in longer timescales needs a different technology. This article works through pumped hydro's round-trip efficiency and variable-speed operation, green hydrogen's electrolysis, storage, and reconversion, real projects, and an efficiency comparison table to lay out the design thinking behind large-capacity, long-duration storage.