The researchers propose that a motorized system similar to a ski lift could pull containers full of sand to a crane at the top of a mountain. The sand can then be sent back down the mountain propelled only by the force of gravity, generating electricity in the process.
The basic concept is similar to a gravity storage technology proposed by the Swiss company Energy Vault, which recently received a greater than $100 million equity investment from SoftBank’s Vision Fund. That technology generates electricity through gravity by lowering concrete blocks in a tower.
Lithium-ion battery storage is the fastest-growing storage type and utilities across the U.S. have procured battery storage as a way to back up intermittent renewable energy. But the length of time that they can deploy energy — typically four hours or shorter for — may not be long enough for the greater and greater amounts of solar and wind resources needed to come online to meet emissions reductions goals.
“High-renewables grids, as mandated by many states, will require extremely long durations of storage, potentially on the order of 10-20 hours to shift variable solar power to cover nights and cloudy days, and weeks or even months to shift energy from high-wind months to lower-wind periods,” Wood Mackenzie head of energy storage Daniel Finn-Foley told Utility Dive. He noted that lithium-ion batteries “scale up poorly,” with costs effectively doubling every time the duration of a lithium-ion battery system doubles.
The authors of the IIASA study claim that mountain gravity energy storage (MGES) can open up possibilities for long-term storage in new locations. Pumped hydropower storage, one of the most common forms of energy storage currently in service, is an example of long-term storage and can deploy stored energy for around 6 to 20 hours.
Recent Comments