Professor Seamus Garvey, lead investigator for the Faculty of Engineering at the University of Nottingham, says that what can be done with end-of-life engines “is an open question”.

“One option is to melt them down to recycle the steel, but we propose to explore another possibility – re-task these engines to become machines that compress and expand air to store and release energy,” explains Garvey.

“Power is increasingly being generated from renewable sources that are intermittent by nature – chiefly, the sun and wind. How to store that off-grid energy for use when needed and not just when generated is a pressing issue to solve.”

The proposition being explored by Volvo Trucks and Nottingham University is to transform existing engine hardware, such as the engine block, crankshaft, and pistons, into effective reversible compressor/expander machines.

These machines compress air to put energy into storage or expand stored compressed air to release the energy again.

The university says that one target application for these machines is at charging stations for fleets of electric buses and trucks.

"The UK would be very nicely catered for beyond 2030 if we had ~50GW of rated power in energy storage facilities,” adds Garvey.

“Each individual truck engine would form the low-pressure stage of a three-stage 250kW compression/expansion train. Thus, in theory we could see up to 200,000 truck engines repurposed to drive that level of power."

John Comer, head of product management, at Volvo Trucks, says: “It is always great to be involved with universities, especially in the UK, that are working on research projects that meet the company’s ethos of ‘driving progress’."

The work is at a very early stage and will see re-manufactured engine hardware from Volvo Trucks gifted to the university, where engineering researchers will adapt the parts and incorporate them into new compression/expansion machines.

The project will run until August 2019 and the machines will form a part of the ‘High Performance Compression and Expansion’ laboratory at the University of Nottingham, which is one key element of a £60m capital project in the Midlands called Energy Research Accelerator (ERA).