The firm has been contracted to deliver the base frame and the weight baskets for the innovative gravity-based prototype, which will begin assembly at its test site at the port of Leith this week.

The 250kW demonstrator’s lattice tower has been fabricated by ESL engineers in Hull.

The system’s custom-built winches and control modules have been made by international winch specialists Huisman at their factory in the Czech Republic and are currently being shipped to Leith.

The full 15-metre high rig will now be assembled at their grid-connected site at the port of Leith for testing to begin in February 2021.

Commenting on the project, Steven Kirk, senior mechanical engineer, said: “AJS is fabricating two vital components for our demonstrator – the grillage (or base frame) will sit on the concrete plinth and will support the lattice tower, and the two weight baskets will be filled on site with high density aggregate, to create two 25-tonne weights.

“These weights will be suspended by steel cables within the tower, and in one test we’ll drop the weights together to generate full power and verify our speed of response. We calculate we can go from zero to full power in less than a second – which can be extremely valuable in the frequency response and back-up power markets

“We’ll then run tests with the two single weights, dropping one after the other to verify smooth energy output over a longer period, alongside a programme of other tests to demonstrate and refine the full capabilities of the system.

“Our two-month test programme will begin in February and will confirm our modelling – and give us valuable data for our first full-scale 4MW project which will commence later in 2021,” Kirk concludes.