This is a great point - there's going to be a lot of used lithium car batteries available x years after electric cars go big, and I don't know of any better use

This is a great point - there's going to be a lot of used lithium car batteries available x years after electric cars go big, and I don't know of any better use for them than grid storage. So it seems like those will be priced at their value for grid storage. Which means that once there's a sufficient supply, they will almost inevitably become a major force in grid storage.