You'd think that in an article specifically about energy storage, in the introductory paragraph, they'd get the units right.
> The Pyhäsalmi Mine, roughly 450 kilometres north of Helsinki, is Europe’s deepest zinc and copper mine and holds the potential to store up to 2 MW of energy within its 1,400-metre-deep shafts.
It's frustrating, every article just repeats "2MW capacity." Gravitricity hasn't announced this project themselves yet, hopefully when they do they give the actual storage capacity.
But I think 2MWh might be correct - in press elsewhere Gravitricity says 500t over 800m produces 1MWh. This is a deeper depth but not that much, and this is very much an experimental project so I think they might be sticking to 500-750t mass. They anticipate larger systems using multiple masses rather than a single larger one. Still, they've also announced a 4MWh project in the UK, so it's not like they see 2MWh as a limit.
It’s a sad reality now, 1Mwh is sloppily called “1MW” when it’s about energy, but “1MW” when it’s about power. It’s just like the ship sailed on 1 kilocalorie.m being called “one calorie” I think we can give up on this one as well.
> The Pyhäsalmi Mine, roughly 450 kilometres north of Helsinki, is Europe’s deepest zinc and copper mine and holds the potential to store up to 2 MW of energy within its 1,400-metre-deep shafts.