That equivalent inertia can only be done for short periods but that's exactly what grids need in stability - there's generally no lack of total generation, just a need to jump in and smooth out spikes.
You can't build a dam for that price, nor could you do it in under 100 days from contract signing as that battery was built. Batteries are definitely the answer here. The 'more spinning mass' answers don't make sense since Australia literally solved the above problem in a much cheaper way already.
Yep, this is the issue. That and land cost. Also pumped hydro is most useful when you need very large capacity storage, whereas for preventing blackouts you need very high capacity fast generating to fix oscillations or to allow more generating capacity to come on line. They are basically acting as decoupling capacitors (except for AC) in this application.
You need two sufficiently large bodies of water close to each other at different elevations. You don't necessarily need two dams - for instance, the Ludington pumped storage plant adjacent to Lake Michigan uses the lake as the lower body.
That equivalent inertia can only be done for short periods but that's exactly what grids need in stability - there's generally no lack of total generation, just a need to jump in and smooth out spikes.
You can't build a dam for that price, nor could you do it in under 100 days from contract signing as that battery was built. Batteries are definitely the answer here. The 'more spinning mass' answers don't make sense since Australia literally solved the above problem in a much cheaper way already.