Preface. Natural gas is finite, but aside from (pumped) hydropower, natural gas is the main way wind and solar are balanced now. Therefore, a tremendous amount of energy storage will be needed in the future as natural gas declines.
The current total energy storage capacity of the US grid is less than 1%. What little capacity there is comes from pumped hydroelectric storage, which works by pumping water to a reservoir behind a dam when electricity demand is low. When demand is high, the water is released through turbines that generate electricity.
This study has quantified the energetic costs of 7 different grid-scale energy storage technologies over time. Using a new metric called “Energy Stored on Invested, ESOI”, they concluded that batteries were the worst performers, while compressed air energy storage (CAES) performed the best, followed by pumped hydro storage (PHS).
But unfortunately, pumped hydro and compressed air energy storage can only contribute a small amount of storage, because there are few places left to put dams and underground salt domes. Eventually, as fossil fuels decline, wind and solar power will need to provide at least 80% or more of the electric power, since biomass doesn’t scale up. Utility-scale electrochemical battery energy storage is essential to keeping the electric grid up in the future, not only to balance sudden surges and dips in intermittent power, but to provide at least a month of energy storage to provide for the seasonal nature of wind and solar, when neither is contributing power to the grid (Droste-Franke, B. 2015. Review of the need for storage capacity depending on the share of renewable energies in”Electrochemical energy storage for renewable sources and grid balancing”, Elsevier).
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alice friedemann, energy skeptic, renewable energy, alternative energy, energy storage,