Sometimes business ideas arrive as a lightbulb moment and sometimes they evolve.

For mechanical engineer Sam Cockerill, the idea of creating a technology platform to help meet the global need for clean, reliable and affordable transport and electrical power was born out of years of frustration.

Working for a large bioethanol producer, he’d witnessed the ‘agonisingly slow’ progression of ethanol blending in petrol and decided to try to speed up the move to clean fuel by helping to create ‘fuel flexible’ engines.

Together with business partner Ed Haynes, he set up Libertine in 2009 to commercialise electrical power generator products known as free piston engines, in which the crankshaft is replaced by a linear electrical generator.

For Mr Cockerill, who designed the crankshaft for the 1996 IndyCar engine in his early career, its an interesting turn of events. “It’s ironic that all the stuff I designed then is all the stuff we’re getting rid of now,” he says.

The linear generator enables manufacturers to use a variety of fuels to generate clean electrical power where battery electrification can’t be used on its own – for example in buses, trucks and package generators.

“Pure electrification is of course best if its economically feasible and practical but there are many applications where that doesn’t work,” Mr Cockerill said.

Libertine spent the first few years building proof of concept systems and talking to potential customers.

The breakthrough came in 2017 when the £100,000 turnover company received £600,000 investment from the Northern Powerhouse Investment Fund and opened its current Sheffield headquarters. It also has a small Colorado office.

By the end of March this year, its turnover had risen to £2.9m.

Mr Cockerill has his sights set on following the same trajectory as fuel cell business Ceres Power, which has been around for about 20 years and last year achieved £31.7m in revenues.

Like Ceres, Libertine’s business model is to license the product rather than manufacturing it to keep capital costs low. Its first commercial licence was issued to Anthony Best Dynamics, a supplier of test equipment to the global automotive industry.

Libertine joined AIM at the end of 2021 after raising £9m with an initial public offering to fund business development and commercial project delivery.

It’s now in the fortunate position of being presented with more opportunities than it can deal with for the first time, according to Mr Cockerill. “That’s good because it means we can be more selective,” he said.

Libertine has also doubled its workforce in the last nine months to 20. "Ceres Power grew from 20 people to a few hundred people in four or five years,” said Mr Cockerill. “That’s absolutely feasible for us.”

The firm works with major original equipment manufacturers, including GE, to help them evaluate the technology and incorporate it into their own development or product. Most recently, it entered a memorandum of understanding with Ashok Leyland.

"We expect to be signing significant licence deals in the next two to three years,” said Mr Cockerill. “The first trucks to have these linear generators on board will be sometime in the second half of this decade.”

Why Libertine in Sheffield is at the forefront of the green transport revolution