In my last two posts (#1 and #2) I explained that to truly make the transition to using renewable energy, we need the utilities on board, and to make that happen, the utilities need an affordable way to store energy.
Batteries are not environmentally or financially the best solution for grid-scale storage. Pumped Storage Hydro (PSH) — the only GW-scale storage technology deployed — and Compressed Air Energy Storage (CAES), with only two plants in operation globally, have given good results. But the construction of these energy storage options is costly, time consuming and wrought with environmental concerns.
So what’s the alternative? The answer may actually lie in digging deep rather than building up.
Pumped storage hydro uses gravity to store energy that is sourced from the grid by raising water to a higher altitude, creating potential energy. That potential is then converted to electricity when the water returns to its original level, passing through a turbine on the way. Storage capacity can be increased by adding mass and/or the storage height