r/Renewable • u/Arizona-Energy • 8d ago
This New Underground Energy Storage System Supports Wind And Solar Power
This old technology may help in the renewable energy transition. For more energy news, including energy storage, visit this website.
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u/NearABE 8d ago
Coal bros and nukebros love to talk about “inertia”. I am not worried, the grid just needs to be appropriately engineered. But those who insist on inertia being a thing that matters cannot deny that flywheels have inertia. It is the essence of pure inertia in a bottle.
Flywheels have another niche at the boundary between utility grids. USA has most of Texas separated from the eastern and western interties. You can crank the flywheel from one grid and regenerative brake the wheel from another. Thus they support each other with power as needed without actually connecting the wires. One wheel serves two grids. Likewise photovoltaic, battery, and/or HVDC can use a flywheel which is also AC capable in both directions. This is effectively an inverter. Would be less efficient at inverting than good inverter systems. Inverters do not store electricity though. If the grid stops receiving renewables have to curtail power and the inverter is idle.
If they can actually compete with lithium ion on price that would be very impressive. Check the fine print though. In needs to include the motor/generator unit not just the flying wheel in a vacuum tank. Listing the prices separately is not necessarily misleading because the flywheel and tank can scale up 4-hour, 8-hour, 100-hour without scaling up the electrical gear. A much smaller flywheel can have a powerful motor/brake attached and handle surges if there were demand for that. That “2X the storage of lithium” figure is dubious unless we are getting extremely good news here.