https://en.wikipedia.org/wiki/Pumped-storage_hydroelectricit...
Flywheels are also used for short term demand spikes. https://en.wikipedia.org/wiki/Flywheel_energy_storage
PS: This is one of those problems that seems a lot more important than it actually is. The current state of the art is fairly cheap and reasonably efficient. Going from 90% to 99% efficiency really does not change much and is a far harder problem.
So, excluding hydro, am I right in that the economics of energy storage do not work (yet)?
ED: Currently, ~4,300 mi is about the limit on economical power transmission. But, that's a long trip.
Though, we already have an electric grid and you can do a lot by simply shifting where each area's supply is coming from. AKA town A get's power from town B's power plant town B, get's power from town C's power plant etc.
Also, a lot of this infrastructure is a ~20+ year problem. So, a 50 billion dollar bill spread over 20 years spread over the entire US is ~8.50$ per year per person.
Even if we rebuild the whole continental US power grid (that's a lot more than $50 billion) to cope with the demands of using storage, it is unclear to me if we can build enough hydro to replace peaker plants. Apparently all other storage technologies other than hydro are cost-ineffective and/or do not have enough scale to solve the problem. Do you know if there is enough geography to go around for all the hydro we need or if there really are any cost-efficient alternatives?
The economics for ~100% up-time only work out when utility's are regulated to act that way. That means spare capacity and backups for your backups. As such I feel a few Peaker plants are actually a good idea. They should not be turned on every day and should be able to pick up the stack when unexpected things happen.
In terms of hydro, we can build them to store ~12 hours worth of US electricity demand. Past that the geography still works just fine, but excess production becomes cheaper than excess storage.
PS: Don't forget we already use pumped hydro. It's just a maximization problem where cost of excess capacity vs. extra storage.
And as I said earlier, the economics don't need to work now in order to justify pilot programs and research, due to the long timelines involved in radically changing how the grid works. The assumption that the economics will work in the foreseeable future is enough.
Can you quantify that?
As far as I can tell the Powerwall is about as cost-competitive as battery storage gets and that's still far more expensive than just using grid power.