Deep Abandoned Mine In Finland To Be Turned Into a Giant Gravity Battery

James Felton reports via IFL Science: One of the deepest metal mines in Europe -- the Pyhasalmi Mine in central Finland -- is to be turned into an enormous gravity battery capable of storing 2 megawatts of energy. [...] Despite the cool name, the idea behind gravity batteries is really simple. During times when energy sources are producing more energy than the demand, the excess energy is used to move weights (in the form of water or sometimes sand) upwards, turning it into potential energy. When the power supply is low, these objects can then be released, powering turbines as our good friend (and deadly enemy) gravity sends them towards the Earth. Though generally gravity batteries take the form of reservoirs, abandoned mines moving sand or other weights up when excess power is being produced have also been suggested. Scottish company Gravitricity created a system of winches and hoists that can be installed in such disused mineshafts. The company will install the system in the 1,400-meter-deep (4,600 feet) zinc and copper mine in Pyhajarvi, Finland. "A study last year by the International Institute for Applied Systems Analysis (IIASA) estimated that gravity batteries in abandoned underground mines could store up to 70TWh of energy -- enough to meet global electricity demands," reports The Independent. "The repurposed mines could also provide economic benefits to the communities that previously relied on the mine for their livelihoods."

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