Gravel store key to eco thermal battery

Start-up Cheesecake Energy Ltd (CEL) reckons that its e-Tanker battery system has the potential to be the greenest in the world and will be able to speed up electric car charging while protecting the grid from overload.

The e-Tanker battery system was one of 13 entries in a competition run by National Highways and Innovate UK, calling for ideas to change the way roads are designed, managed and used.

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 resource-intensive and the majority of production materials cannot be recycled.

The e-Tanker system by comparison just uses old Volvo truck engines and some gravel.

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 Volvo truck engines again which drives the electric motors in reverse to generate electricity.

CEL claims that that the system will be 30% to 40% cheaper 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.

National Highways head of innovation Annette Pass said: “Cheesecake’s project is an excellent example of the changes that are being made to reduce carbon in the transport industry. It also plays a part in National Highway’s net zero carbon plan, which will see a rapid cut in carbon from road construction, maintenance and operations, and supports the transition to zero emission vehicles.  

“Currently, 95% 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. Innovations like this one will help us achieve that.”

CEL’s prototype system will soon be installed in a depot in Nottingham for charging a fleet of electric vehicles.

CEL chief commercial and product officer Mike Simpson said: “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.”

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