Comment by coryrc

They get used in burst cycles -- like 10 days straight at harvest time, other times not started for months. Battery cost per kwh used is very low amortized over its full lifespan, but if you only use it to 1% of its capability your costs are now 100x higher.

Now, hang a high voltage wire down from a big-ass catenary, so you don't need batteries, and it'll be cheaper upfront and in use, but nobody does that because of 1. safety 2. if everybody did it the grid would need upgrades