Edinburgh-based Gravitricity is looking to raise £40 million to fund construction of three green energy storage facilities within the next five years.

The company has appointed corporate finance specialists Gneiss Energy to spearhead the fundraising campaign, which will target both industrial investors and specialist impact funds. The three demonstrator projects are aimed at proving the viability of Gravitricity's technology, which stores the output from wind and solar farms until it is required at times of high demand.

The company is already planning a full-scale demonstrator at a former mine in the Czech Republic, as well as a purpose-built new shaft scheme in northern England.

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“In parallel to our three pathfinder projects, we are also developing a portfolio of development sites worldwide, with project partners already in place in mainland Europe, South Africa, India, Pakistan and Chile," commercial director Robin Lane said.

He added that Gneiss is the "ideal partner" to help attract the right kind of investor. Set up in 2016, Gravitricity has to date raised £7.5m, about half of which was private investment alongside public support from the European Investment Bank (EIB), Innovate UK and BEIS.

Storage technologies will be fundamental in the transition to green energy sources, with analysts at Bloomberg New Energy Finance predicting that the market will grow by 21 per cent annually with a total global investment of £662 billion by 2040.

“Lithium batteries are inherently suited to shorter duration storage of around one to two hours; however, future energy scenarios will also require increasing amounts of longer duration capability for which lithium ion is not well suited.

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“In addition, supply chain constraints and geopolitical uncertainty mean that home-grown solutions beyond batteries will be required," said Nick Edgar, head of renewables at Gneiss.

“Gravitricity is developing technologies which will last for decades and can cycle rapidly between charge and discharge without any loss in performance, as well as offering long duration capabilities – all characteristics which will become increasingly valuable to grid operators as renewable penetration increases."

Earlier this year the company also unveiled its mid-scale hydrogen storage solution, H2 FlexiStore.