Storing energy by suspending weights in disused mine shafts could be cheaper than batteries for balancing the grid, new research has found. According to a report by analysts at Imperial College London and seen by BusinessGreen, gravity-fed energy storage systems can provide frequency response at a cost cheaper than most other storage solutions. Gravity-fed systems use a heavy weight – up to 2,000 tonnes – suspended in a deep shaft by cables attached to winches. When there is excess electricity, for example on a windy day, the weight is winched to the top of the shaft ready to generate power. This weight can then be released when required – in less than a second – and the winches become generators, producing either a large burst of electricity quickly, or releasing it more slowly depending on what is needed.
Business Green 19th April 2018 read more »