What it is
Storage refers to technologies that hold energy for later use: charging when electricity is cheap or abundant (midday solar) and discharging when it’s scarce or expensive (evening peak demand).
Storage technologies
- Lithium-ion batteries — the same core technology used in EVs and phones, dominating today’s grid-scale storage market, typically packaged into installations called Battery Energy Storage Systems (BESS) and usually sized for 2–4 hours of discharge.
- Pumped hydro — pumping water uphill to store energy, then releasing it through turbines to generate electricity on demand.
- Longer-duration technologies — flow batteries, thermal storage, compressed air, aimed at storing energy for many hours or days rather than the few hours lithium-ion batteries typically cover well.
Why it matters
Storage is the direct technical answer to the intermittency problem described in the Energy / Grid topic: it’s what lets a grid rely more heavily on solar and wind without needing fossil-fuel “peaker” plants to fill the gaps. It also connects to Mobility, since EV battery manufacturing and grid storage draw on overlapping supply chains and increasingly the same underlying battery chemistry research.