Gravitricity, an Edinburgh-based green engineering start-up, is working to make this a reality. In April last year, the group successfully trialled its first gravity battery prototype: a 15m (49ft) steel tower suspending a 50 tonne iron weight. Inch-by-inch, electric motors hoisted the massive metal box skyward before gradually releasing it back to earth, powering a series of electric generators with the downward drag.
The demonstrator installation was “small scale”, says Jill Macpherson, Gravitricity’s senior test and simulation engineer, but still produced 250kW of instantaneous power, enough to briefly sustain around 750 homes. Equally encouraging was what the team learned about their system’s potential longevity.
It seems like a neat solution. The globe is pockmarked with disused mine shafts deep enough to house a full-sized Gravitricity installation, which will stretch down at least 300m (984ft), and possibly much further. There’s political will to make it happen too, Blair says, with policymakers keen to tap into public enthusiasm for a so-called “just transition” – the notion of a new, low-carbon economy that secures the livelihoods of fossil fuel workers and their communities. And so, with enough funding, a subterranean prototype (most likely located in the Czech Republic) should be functioning by 2024. First, though, a series of challenges must be overcome.Can gravity batteries solve our energy storage problems? – BBC Future