Flywheels are an old technology for storing kinetic energy in a spinning wheel or tube. Punch Flybrid has added inverter control technology to the mechanical principles, initially for Formula 1 motor racing until the hybrid engine rules were changed 15 years ago, effectively banning the technology. Since then, Punch Flybrid has been looking for markets and found the perfect one – tower cranes, or more specifically their generators.
Generators on construction projects are typically sized for peak loads. However, most of the time they run at low load factors, which results in poor fuel economy and high emissions. This is especially the case when running equipment like tower cranes, which oscillate between total idleness and full power.
By connecting a Punch Power 200 box to the generator set, the flywheel load-levels the peak power that the generator set has to deal with. The Punch Flybrid system delivers energy immediately at high power during an increasing load step and captures excess energy (in a spinning tube) during a decreasing load step.
Punch Flybrid technology thus enables a smaller generator to be able to cope with these occasional surges of demand and take the place of a larger generator. With the red diesel rebate ending next spring there is suddenly a huge incentive for construction sites to use the least thirsty, smallest possible generator.
Word has got out: Kier, Bowmer & Kirkland, John F Hunt, Sunbelt and Stuart Energy have all realised the cost-saving benefits of Punch Flybrid’s device. But Select Plant Hire has taken the lead.
Punch Flybrid managing director Tobias Knichel said: “It takes courage to be first. Select Plant Hire was the first company to approach Punch Flybrid for a technical collaboration to integrate flywheel energy storage directly onto tower cranes.
“Working together with the Select team for the last few months demonstrated that Select not only understand the technical aspects of tower cranes very well, but they have also shown an outstanding level of support and forward thinking to their impressive customer base. This has convinced us that partnering with Select is the right next step for Punch Flybrid.”
Select Plant Hire connected the Punch Flybrid technology to a crane at one of its London projects for a month. Over the course of the 213 operating hours it saved over 1,300 litres of fuel (50% saving) and cut 3,478.5kg of CO2 pollution.
Select managing director Alex Warrington said “At one of our London sites we reduced the generator size on our CTL1600 (66-tonne luffer) from 800kVA to 500kVA, with the opportunity for further reduction. It instantly generates substantial CO2 savings and saves significant costs of rental – it makes sense on every level.”
Main contractor Bowmer & Kirkland, a Select customer, has four of the first 10 Punch Flybrid units on its sites. Each unit hired saves 44,000 kg of carbon per year, according to Bowmer & Kirkland’s group crane manager, Dave Shooter. He said: “These next generation machines have huge benefits and give us many advantages. Select Plant Hire has been helping to ensure our sites have the latest lifting technology, which is ensuring that we get maximum efficiencies from our tower cranes. We are also pushing to get carbon reducing Punch Flybrid on all our sites with tower cranes."
Sunbelt Rentals has supplied Kier a Punch Power 200 box for a tower crane on its Shakespeare North Playhouse project in Prescot and achieved 40% fuel savings.
The bigger the crane, it seems, the greater the savings.
It looks like, suddenly, Punch Flybrid has found its application and its moment. Ten exist currently and are in the field in the UK; the next 50 Punch Flybrid units are expected to be delivered to customers this month.
With its Formula 1 roots – the company is still based on Silverstone Park – Punch Flybrid initially kept its focus on the automotive industry after the F1 market was closed to it. Its flywheel technology can deliver 20% fuel savings in a car. It only later came to realise that, when put on a construction site, one generator can save the same fuel per day as 50 cars. Cue sudden pivot. “80% of our business is now focused on the construction industry”, said Tobias Knichel.