City skyscrapers to become ‘green batteries’ of the future

City skyscrapers could become green batteries of the future – thanks to a new form of energy storage patented by a UK firm.

Edinburgh start-up Gravitricity has developed an innovative energy battery which works by raising multiple heavy weights – totalling up to 12,000 tonnes – in a deep shaft and then releasing them when energy is required.

Analysts predict the system could store energy at half the levelised cost of lithium-ion batteries – and already the greentech pioneers are planning to install their invention in disused mineshafts across Europe.

They now believe they can install their technology in the foundations of new skyscrapers – turning the buildings into green energy stores.

“Our idea is very simple. We use excess green energy to lift massive weights to the top of a shaft. These can then be stacked and released when required, delivering energy rapidly back to the grid,” says Gravitricity Managing Director Charlie Blair

“In the early years we will install our technology in disused mineshafts as this will help keep the cost down.

“But in the future, we will be able to sink purpose-built shafts wherever they are required – and the foundations of city buildings could be ideal.

“New skyscrapers bring substantial new electricity demand, and by building storage in the heart of cities we can massively reduce the requirement for very costly and disruptive grid upgrades.

“At the same time, our system means that future skyscrapers could reduce their environmental footprint and help cities decarbonise their energy needs.”

Blair says their 24MWh system – which comprises 24 weights of 500 tonnes – could power 63,000 homes for one hour. The total weight is equivalent to 84 blue whales.

The energy innovators have already received a £640,000 grant from Innovate UK, the UK Government’s innovation agency, and have teamed up with Dutch winch specialists Huisman to build a 250kW scale prototype of their idea

“The climate emergency means we need to find new ways to capture and store green energy so we can use it when we need it,” Blair says.

“We think city skyscrapers could be an exciting part of that future,” Blair concludes.