Gravity-Based Energy Storage 'Half the Price of Li-Ion,' Begins Trials 2021

Gravitricity's gravity-based energy storage concept is set to begin trials in Scotland spring 2021.
Brad Bergan

A new prototype gravity-based energy storage system is in the works, promising to store energy at half the price of current market-leading lithium-ion (Li-ion) batteries — with tests beginning next spring, in Scotland, according to the company website.


Gravity-based energy storage beats lithium-ion batteries

Based in Edinburgh, Gravitricity's concept is to raise weights of roughly 13,227 tons (12,000 tonnes) up into a lattice tower, and then release them into a deep shaft — releasing and discharging potential energy according to how much is needed.

A Dutch winch specialist Huisman, along with a UK engineering firm Kelvin Power, is building the 250 kW version of the concept — as part of a $1.3-million (£1 million) project, reports Recharge News.

"Our demonstrator will use two 25-tonnes [27.55-U.S.-ton] weights suspended by steel cables. In one test we'll drop the weights together to generate full power and verify our speed of response. We calculate we can go from zero to full power in less than a second — which can be extremely valuable in the frequency response and back-up power markets," said Miles Franklin, lead engineer at Gravitricity, according to Recharge News.

"We'll then run tests with the two single weights, dropping one after the other to verify smooth energy output over a longer period, alongside a programme of other tests to demonstrate and refine the full capabilities of the system," Franklin added.

This comes on the heels of an earlier study from Imperial College London, which exemplified how well-suited the technology is to taking on a grid balancing role, capable of rapid frequency response services for electricity network operators. In a frequency response situation — where 700 cycles per year are required at 15-minute durations, with a 4MW power output — the new gravity-based system is predicted to have a levelized cost (LCOS) of $141 per kW per year, "outperforming all alternatives," Recharge News reports.

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Gravity-based energy storage 'half the price' of Li-ion

The report showed electricity released using a typical 10 MW Li-ion battery would have a $367 per MWh cost through its lifetime, compared with the lower cost of $171 per MWh for Gravitricity's electricity project.

That's half the price.

Competition is strong among the race to claim the prize of becoming the next-gen energy storage alternative, and replacing Li-ion at the head of the energy storage market. Some rivals of Gravitricity's include the liquid air "cryo-batteries" of UK developer Highview Power, Zinc8's zinc-air design out of Canada, and vanadium redox flow batteries from the UK-Canadian joint venture Invinity.

Each competitor with stakes in the energy storage game claims their technology can outclass Li-ion on long-term LCOS, reports Recharge News.

Li-ion batteries hold a monopoly on the world's energy storage sector, but new battery chemistries — singled out next to high-temperature heat pumps and green hydrogen by the international energy consultancy DNV GL — will likely lead to a "second-phase" transition in technologies. We can expect them to build on top of the expanding solar- and wind-power shift in energy infrastructure in the coming years.

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