Finding ways to store power generated by the sun when the sun is not shining is essential if the world is to move away from fossil fuels.
Gravity batteries is one technology that can store power from renewable energy generators. Gravity is free, clean and easily accessible, without the complications of producing hydrogen or the environmental and human rights concerns linked to some lithium mining.
When the sun shines, surplus power is used to lift up a heavy weight or to pump water uphill and when solar energy is no longer available and power is still needed, the weight or water is slowly lowered and produces electricity turning electricity-generating winches or turbines. The weight or water can also be released faster to produce a burst of energy to meet unusual demand load.
The technology is evolving quickly and, several companies have started projects that applies it in different settings, such as mineshafts. In the US, ARES Nevada is developing a 50MW GravityLineTM merchant energy storage facility on a working gravel mine in Nevada. This project will employ a fleet of 210 mass cars, weighing a combined 75,000 tons, operating on a closed set of 10 multi-rail tracks.
In this 2020 video, Gravitricity explains how to use gravity to store excess energy
To learn more:
How gravity batteries will help us switch to renewable energy - World Economic Forum (July 12, 2022)
Gravity-based batteries try to beat their chemical cousins with winches, weights, and mine shafts - Science (April 22, 2021)