These are for buffering/load-balancing, not storage. Note the <500 milliseconds response time, that's way faster than pump hydro can respond, even with compress

These are for buffering/load-balancing, not storage. Note the <500 milliseconds response time, that's way faster than pump hydro can respond, even with compressed air. A typical UK household uses close to 50kWh of energy a day, most of it on heating and cars. So, in a zero-carbon future, you'd need a 10-foot shipping container per 20 homes to give them each a single day of storage. You'd need >10x that to ride out a windless cold snap (common in the UK where I am—we even had 2 weeks of no wind power in the height of summer last year so ran 60% gas during the hottest week ever recorded). Grid-scale storage is tens of TWh, still way beyond any battery technology. These are MWh-scale systems. Useful, but not grid-scale storage. A grid would need tens of millions of these. At $17/kWh we're talking $500 billion. They would be useful for keeping the air-con running on hot nights in solar-powered countries though.