This Innovative New Technology Turns Abandoned Mines Into Sustainable Energy Storage – SlashGear

How UGES works comes down to gravitational “potential” energy, according to Energies. The simplified physics of the proposed UGES plan is that when an object is up high, it has “potential energy,” because it has the potential to unleash a lot of energy when it falls. If you then actually let the object fall, the potential energy turns into “actual” energy in the form of kinetic motion.

With other renewable energy sources like solar or wind power working during the day, there’s usually more energy generated than actually needed to power cities. The goal with UGES is to store the excess energy, which is where sand-filled mineshafts come in: the excess energy would be used to lift sand out of the mines. Once the sand is topside, it would wait with potential energy stored up and ready for future use. When energy demands later exceed the supply, the sand can be dropped back into the mine, generating power using regenerative braking technology. Then the cycle repeats as necessary (per Energies).

Traditional batteries are tough to recycle and are prone to slowly losing their battery charge over time, which is not only wasteful, but a real problem for renewable power generation. But a pile of sand sitting beside a mineshaft holds its potential energy forever. With researchers estimating UGES could store 579 GWh of energy in the U.S. alone, this is probably the greenest use an old coal mine could ever hope to see.