New plans to deliver hundreds of specialist underground hydrogen stores have been confirmed. Scottish-based energy storage developer Gravitricity has signed a memorandum of understanding (MoU) with infrastructure business VSL Systems UK, working on developing steel-lined underground rock shafts.
The two businesses are looking for additional funding, enabling them to deliver a scale pilot project in the next few years. Within the plans, each rock shaft would be six metres in diameter and reach a depth of 365 metres. Gravitricity explains that one store could contain up to 100 tonnes of green hydrogen, and 1000 stores could meet around a quarter of the UK’s anticipated 2050 hydrogen storage requirements.
Charlie Blair, the MD of Gravitricity, explains that green hydrogen is a critical fuel for our future, particularly in selected industries, such as heavy transport, where electrification isn’t feasible. Blair highlights that the proposed lined rock shafts represent the safest and most affordable technique to store large amounts of hydrogen near where it will be utilised. It can be challenging to transport hydrogen, so it makes complete sense to develop hydrogen storage facilities near the source of renewable energy, which can provide green hydrogen.
The existing options for storage are underground salt caverns and above-ground storage sites. Blair explains that while salt caverns provide scaling opportunities, they lack flexibility as they only exist in some locations and above-ground system lack scale. Blair believes their project offers a safe and affordable option to meet our growing hydrogen needs.
The planned stores can be built wherever needed and are not reliant on geological factors, meaning an individual or several stores can be located near renewable-power green hydrogen facilities. Blair believes a single rock shaft could store green hydrogen produced by a 460MW offshore wind site and be emptied and refilled daily, while multiple facilities could utilise considerable amounts of ‘wasted’ wind energy.
Gravitricity has selected various sites for the UK demonstration project and is discussing the process with the site owners. The business recently finalised a feasibility study with partners ARUP and funding by the Government-based BEIS HySupply programme. The results showed it is technically and commercially feasible to store large volumes of compressed hydrogen in underground lined rock shafts. Blair reiterates that for green hydrogen to become a dominant fuel of the future, we must find ways to store large amounts of hydrogen safely and close to where it will be consumed.