PUNCH Flybrid technology trialled on HS2 cranes

carbon emissions, HS2, innovation, technology, UK,


Technology developed by engineering specialist PUNCH Flybrid to cut fuel consumption, carbon emissions and improve air quality on HS2 construction sites.

As part of HS2 Ltd’s Innovation programme, a tower crane on the railway’s Euston approaches site that would normally be powered by a 500kVA diesel generator to lift loads of up to 24 tonnes is driven by one less than half that size.

The site where HS2’s London tunnels surface is operated by the project’s tier one civils contractor Skanska Costain STRABAG joint venture (SCS JV).

The significantly smaller 200kVA generator’s power difference is bridged by pairing it with an energy storing flywheel system developed and supplied by Silverstone-based engineering specialist PUNCH Flybrid.

Incorporated inside the PUNCH Flybrid-supplied unit (pictured), the flywheel, measuring just 35cm in diameter, is housed in a vacuum chamber to all but eliminate energy-sapping resistance that would result from contact with the air.

The technology matches the power of larger, thirstier generators by using the 200kVA generator’s surplus power during the crane’s low load periods to charge the spinning flywheel to very high speeds, equivalent to a ground speed of 550mph. The kinetic energy stored by the flywheel can then be quickly released to support the generator when the crane demands maximum power to lift heavy loads.

The UK firm’s expertise was initially deployed in F1 motorsport. It was subsequently put through its paces in endurance racing, including the famous Le Mans 24 Hour, before both sports opted to focus exclusively on electric battery-based hybrid technology – now widely used in passenger cars.

Able to perform up to 10 million charging cycles compared to 3,000 of a typical electric vehicle battery, PUNCH’s Flybrid’s flywheel know-how is – through HS2’s Innovation programme – proving to be the perfect fit for the extreme and repetitive demands of the construction industry.

Such is the hybrid system’s efficiency. In May 2022, the Euston trial more than halved the diesel consumption of a single tower crane to 6.3lt per hour, thereby saving 4.8 tonnes of carbon – equivalent to the average monthly CO2 emissions of 40 family cars.

Designed by PUNCH Flybrid to also work with hydrogen, mains electricity and battery-powered generators, the innovation trial is a significant step toward HS2’s ambition of diesel-free construction sites. 

“We developed our flywheel technology to improve performance and efficiency at the very pinnacle of the automotive industry, but its fundamentals mean there are opportunities to deploy its benefits in other sectors,” Tobias added. “That’s why we’re very pleased to have an opportunity to utilise the technology for the construction industry under HS2’s Innovation programme.”

Linked with HS2 after applying to Innovate UK’s Innovate at HS2 2020 competition, the partnership with PUNCH Flybrid demonstrates how linking Britain’s largest infrastructure project with industries beyond the construction and rail sectors has the potential to create long-term benefits and opportunities throughout the wider economy.

Innovate UK is delighted to work with HS2 in the delivery of innovation for this prestigious programme, and through this collaborative working, a new relationship between HS2 with PUNCH Flybrid has created the opportunity to explore the potential offered by a tried and tested automotive technology to save fuel, cut costs, reduce CO2 emissions and create possibilities for future economic growth in the high-value manufacturing and engineering sectors,” says Innovation Lead for Rail at Innovate UK, Kelvin Davies. 

PUNCH Flybrid’s HS2 trial ends in late 2022. 

Source: © High Speed Two Ltd 2022

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