The Weekend Wonk: Pumped Hydro is the Energy Storage Sleeping Giant

Great new piece from the incredibly useful “Just Have a Think” series, summarizing current potential for pumped hydro energy storage.
Pumped hydro is the oldest and most reliable energy storage technology, using the potential energy of water in a high reservoir, as it falls to a lower reservoir. Pump the water up when you have excess power, let it fall when you have a deficit.

The concern has been that appropriate sites for this kind of storage are running out, because many of the remaining potential sites are in environmentally sensitive areas.

I’ve been interviewing engineers who are looking at a new wrinkle in the space, that actually remediates current environmental problems, while invigorating left-behind rural communities. That’s because they use abandoned mine shafts, or which there are tens of thousands across North America and the world.
Basic ides is, upper level chambers in mines become the energy storage portion where water is pumped up during off-peak hours, and then allowed to fall thru a turbine to lower chambers when power use peaks.

Most recently, spoke to Roman Sedortsov at Michigan Tech University, who is looking at metallic mines, (copper, and iron) across the upper midwest especially. Also, a year or so ago, spoke to Peter Schubert at University of Indiana/Purdue, who is looking at the same thing for abandoned coal shafts.
The beauty is that these sites are already permitted, have good road and electrical transmission access – thus taking care of some of the most onerous bureaucratic barriers. In addition, many of these are currently environmental nuisances, leaking acidic water and toxins.
This kind of development will remediate the problem, remain completely invisible below ground, and have ready access to grids not far from major load centers.