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Can ‘gravity batteries’ boost our energy storage capacity?

Cutting-edge technology could harness the universe’s fundamental force to help our green energy transition.

Generating green energy is largely dependent on Earthly forces. When the sun is shining, or the wind blowing and the waves rolling, we’re good.

When skies darken and conditions calm, however, our supply lines of sustainable power are diminished and that’s a problem.

In stark contrast to our carbon neutrality ambitions, we supplement these low yield periods by ramping up the burning of fossil fuels.

The phrase ‘one step forward, two steps’ back comes to mind.

Climate tech points to lithium-ion batteries and hydrogen as two of the most promising avenues to achieve a net zero future, but engineers are also looking for ways to effectively store green energy from renewable sources – so it isn’t intermittently generated and used at that moment.

Essentially, we need to find ways to retain clean power when there’s an abundance so it can be released in increments into the grid during calmer periods.

This has long been a bugbear of innovators in the industry, but finally some neat ideas are starting to show promise. The latest, which sounds a little barmy in theory but relatively simple in practice, involves harnessing the limitless force that surrounds us all: gravity.

‘What goes up, must come down’ is the Newtonian logic underpinning what are known as gravity batteries. These ingenious contraptions look like 50ft towers, but crucially serve only to keep a giant weight suspended.

As excess energy is fed into a battery using renewables, the weight is slowly pulled higher. Then, when incidental factors prevent solar, hydro, and wind generators from doing their thing, the weight will lower causing its reinforced cables to drive a series of motors at the summit.

This releases the stored electricity and makes up for any green deficit within the grid. No need for fossil fuels at all.

Prototype gravity-based energy storage system begins construction
Credit: Gravitricity

When fully operational, these gravity batteries can reportedly release between 1 megawatt and 20 megawatts for up to eight hours. Running at full capacity, this system could reportedly power 63,000 homes for every hour that it discharges.

Another core advantage of this concept is that it can be deployed underground too. Disused mine shafts are the perfect subterranean space for gravity batteries, and would allow us to actually reclaim fossil fuel depots for green energy development. How poetic is that?

If you’re thinking that this is sounding a little farfetched, a UK company aptly named Gravitricity is currently looking to build a full-scale underground system somewhere in Europe. Czechia’s Staric mine is highlighted as a potential candidate for its pioneering project, which aims to be up and running as early as 2023.

As things stand, gravity batteries are arguably the most practical and encouraging means of maximising our renewable energy sources. Paired with exciting carbon capture initiatives, hopefully we’ll make enough of a dent in emissions to stay on track for our carbon goals.

 

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