How will it play out over time? That’s impossible to predict. But if batteries get to the pump-up price point then they are likely to dominant the grid.

Full disclosure – I’ve been off the grid for over 20 years. I know that batteries work very well for storing electricity, I’m running on mine right now because the Sun has moved far to the west.

Batteries are really low involvement technology. They passively accept power when there is extra and give it back when the grid desires. There’s no dealing with a spinning turbine.

Utility systems, given the right price, can park large batteries around their territory and worry little about them. Use them, replace them when they wear out.

By distributing them around the grid lots of supply issues are minimized. Smaller transmission lines can be utilized and neighborhoods are less likely to go dark when a line goes down.

Utility managers, assuming large scale batteries mature, can simply contact the factory and order more storage. It can be trucked in and plugged in. No years of site location, permitting and construction.

If there is more storage in one area than needed the container can be loaded up and moved.

I think that modular aspect of batteries is going to make them very attractive.

You can compare them on the basis of cost. Right now pump-up is probably cheaper, but new battery technology looks like that may not hold.

You can compare on life expectancy. But that’s really just a cost comparison. It wouldn’t matter if batteries lasted only a week if they were sufficiently cheaper to replace over the 75+ life of a pump-up project.

You can compare them on difficulty to site. Shipping container sized batteries are easy to plop down on an appropriately zoned piece of land. Obtaining land and getting it approved for pump-up is a major task.

You can compare them in terms of which is easiest to locate near point of generation or point of use. Batteries win this one hands down.

I’m neither a battery nor a pump-up advocate. As well I don’t advocate for CAES, thermal, or any of the other storage solutions being investigated.

I don’t think there will be a ‘one size fits all’ solution. But what I am seeing is that there seems to be a lot more activity and investment surrounding grid battery storage than any of the other technologies.

We’re going to need massive amounts of new storage. The big question is which will give us the least cost/most usable storage.

We’ve got tons of existing dams which can be converted to storage. And some dams currently in use for generation could be upgraded for storage.

I’ve lived near two CA dams which trapped spring runoff and used it for generation. Later in the year water levels dropped (less head) and generation hours were cut in order to stretch generation days.

If we built small holding reservoirs below those dams we could add additional pump/turbines and use them to gen large morning/evening output, replacing water during high wind/solar hours.

Then, during the infrequent periods of little wind/sun we could run them full out to make up for shortfall.

One other advantage for pumped I’ll hazard to guess is that for the most part the investment in pumped has already been made so for the operators this is like free money.

What we don’t know, and won’t know for a while, is cost per cycle for pump-up and battery storage.

Battery has a huge location advantage – much easier to find locations and capable of being distributed which cuts transmission/infrastructure costs. Battery is also quicker to bring on line and can be relocated if desired.

Old factory sites should be ideal for large scale battery storage. They won’t object to sitting on brown fields, the land should be relatively inexpensive, and there should already be large power lines to the location.

Current design is to fit the battery bank into stackable shipping container sized packages. Build them in factories, rail/truck them to location, unload and plug in. When they’ve reached their cycle life end, truck/rail them back to the factory for rebuilding.

Revenues will double meaning much faster return on investment. Actually more than double when you add in money earned by grid smoothing in addition to two storage cycles per day.

Operating/maintenance costs will stay roughly flat. (Except for moving parts wearing out sooner.)