The ‘Site of the Future’ project was led by Network Rail and Colas Rail.

It used solar and battery technologies from Prolectric Ltd instead of diesel generators to save 6,000 litres of fuel, and more than 15 tonnes of CO₂ during a 14-day project.

Nick Matthews, Network Rail programme engineering manager, said: “In business improvement, generally a one or two percent gain is considered significant, so to achieve 97% at the first attempt is simply staggering.

“Saving close to 6,000 litres of diesel is the same as driving a family car at 40 mpg twice around the circumference of the world.

“It’s also very clear where we have learnt the lessons from Llanwern so we can close that small gap.

“We really want to get to that 100% fuel free-figure by the time of our next challenge, planned for a rail renewal project later in the summer.”

Solar lighting and power generation technologies were used across the site covering more than 21-acres.

This included access roads, the welfare cabin area, car parking and the track working area itself, where the London to Cardiff main line meets the Llanwern steelworks spur, near Newport.

Three 25kW solar generators replaced conventional diesel generators providing light and heat for seven welfare cabins, including site offices, a canteen, toilets and a drying room.

A total of 21 solar tower lights illuminated the site compound, car parking and work preparation areas, as well as being deployed on the trackside.”

Matthews added: “It was just as important to explore and extend the range of renewable applications, including a new solar-powered camera security system.

“We were also able to demonstrate the versatility of using portable lithium battery packs, recharged as necessary from the solar generators to power dust suppression systems, water cooler stations and point motors.”

Ryan Ballinger, production manager for Colas Rail, said: “We have worked closely to drive the development of suitable on-site solar tower lights and walking lights.

“Now at Llanwern we have been able to add solar generators for the first time and moving forward we want to add smaller plant and tools such as disk saws and band saws.

“There’s no doubt these technologies are going to be a complete gamechanger. Now, we need to push on and get to the point where they are just business as usual.”