Comment by cogman10
2 days ago
If you look at the energy density, cost/kwh, and lifetime maintenance of most of those, you'll find that batteries handily win. Further, batteries have room for innovation and growth in all those categories.
We won't, for example, make a more cost-efficient flywheel or heat storage. They are effectively as efficient as they'll ever be.
IMO, it necessarily has to be batteries. The other alternatives are nowhere near as good.
On the other hand, you need to buy a new set of batteries every 15 or so years. The other things you mentioned generally don't need regular replacement, and when they do, it's not the whole setup.
You don't need to replace the whole setup, just the batteries. All the power electronics and interconnects are already there and will last as long as they last.
You also don't technically need new batteries almost ever. Batteries (typically) don't really die, they just lose capacity. After a 15 year runtime instead of storing 10mWh they now store 7mWh. That's still 7mWh. After another 15 years it'll be down to around 5mWh.
At grid scale I'd imagine that pumped hydroelectric storage would beat batteries for TCO, but there are significant geographic constraints.
I mean, it is a literal pipe dream :)
Batteries can be deployed nearly instantly. My power company is planning on building a new battery plant next year, it announced it the year prior.
I know a pumped hydro plan that has literally been in the works for the last 20 years and shows no sign of actually being started (still being planned).