Gravel thermal cell innovation could support EV charging in remote areas

An innovative thermal energy storage system that uses gravel to store electricity has been developed by an entrant in a multi-million-pound competition funded by National Highways.

Start-up Cheesecake Energy Ltd (CEL) says its 'eTanker' battery system has the potential to be the greenest in the world and could support electric car charging while protecting the grid from overload.

The company was one of 13 successful entrants in an innovation competition run by National Highways and Innovate UK. The competition, which recently ended its development stage, encouraged the country’s most creative minds to come up with ideas to change the way roads are designed, managed and used with innovations that can be taken up across the transport sector.

CEL’s energy storage system uses compressed air and thermal storage rather than rare metals like cobalt that are needed to make lithium-ion batteries. The production of lithium-ion is very resource-intensive and the majority of production materials cannot be recycled.

The eTanker system by comparison uses second life Volvo truck engines and gravel, both low cost and widely available, resulting in much lower capital costs and minimal environmental footprint.

When air is compressed it heats up and this heat is stored in a tank containing 20 tonnes of gravel while the air is stored in pressure vessels. When the electricity is required the compressed air and heat are used to turn the truck engines, driving the electric motors in reverse to generate electricity.

CEL says that that the system will achieve costs that are 30 to 40 per cent lower than the cheapest battery currently available.

The system uses established mechanical processes and can be charged using energy from the grid or a renewable source. Production of these units at scale would be able to draw on the existing skilled workforce and hardware from the automotive manufacturing sector.

Annette Pass, Head of Innovation at National Highways, said, “Cheesecake’s project is an excellent example of the changes that are being made to reduce carbon in the transport industry.

“Currently, 95 per cent of the strategic road network is within 20 miles of a charge point, but they only cater for a small number of electric vehicles, and as those numbers increase it’s very important that we can cater for that, particularly on remote parts of our network.”

CEL has already started on the next stage of the company’s development, with work continuing on its prototype system that will soon be installed with a Nottingham-based depot for the charging of a fleet of electric vehicles.

CEL Chief Commercial and Product Officer, Mike Simpson, said, “Participating in the innovation competition has been a tremendous experience for CEL. Being able to develop our prototype system in collaboration with National Highways has offered unique insights that will undoubtedly shape our product offering as we bring our energy storage systems to market, globally.

“We hope to continue working with Innovate UK and National Highways to help mitigate the effects of climate change by providing more sustainable solutions to decarbonise the transport sector.”

National Highways has run two hugely successful multi-million-pound competitions, worth £20 million. The funding came from two of the company’s designated funds – ring-fenced money set aside for innovation. The competitions were facilitated by Innovate UK.

Karla Jakeman, Connected Travel lead at Innovate UK said, “Innovate UK are delighted to be supporting innovation in the transport sector through the Small Business Research Initiative (SBRI). This proven route to develop test and trial innovation offers vital funding to innovative organisations – helping them to develop solutions in partnership with the public sector.”