It all started with the Eddi, which took the excess energy generated from domestic solar panels to heat water. These were made by Myenergi – Lee Sutton and Jordan Brompton’s business that they were funding with £180,000 of their own money. They produced the devices in an almost windowless business unit in the small village of Binbrook, in Lincolnshire.

“We were soldering and using second-hand manufacturing equipment bought from local businesses or the internet,” says co-founder Brompton, “and getting local grants, business loans and maxing out our credit cards to build the order book.”

Brompton and Sutton had previously worked together in the renewables industry and founded Myenergi in 2016 to give homeowners energy independence.

“After the Eddi, we turned our attention to diverting spare power to car batteries.

We released Zappi in 2017, which really put our business on the map.” By 2019 the pair needed more investment. “We had the orders, but couldn’t afford the raw materials to produce them,” recalls Brompton.

The pair received £1.8m from angel investors, including former Tesco CEO Sir Terry Leahy and venture capitalist Bill Currie, who had previously backed Asos, THG and Boohoo. Both are now directors.

Myenergi moved to a 66,000 sq ft purpose-built factory near Grimsby during Covid-19, but with this came supply chain issues and a microchip shortage. “We had to redesign our products to work on a new chip to maintain orders,” recalls Brompton.

Last year, Myenergi received £30m of investment from Energy Impact Partners to support growth, with its products now sold in Germany, the Netherlands, Australia and Ireland. HSBC has also provided the company with £30m in debt financing and accounts filed for the year to June 2023 showed that turnover grew to £67.6m against £53.8m the year before.

“You set out all bright-eyed and bushy-tailed and thinking of success,” says Brompton. “You always dream big, but when it comes to fruition, it’s crazy. All the time, we’ve just rolled with it and ploughed everything back in.”

Read about more inspirational businesses in our Growth Stories series.