Reducing CO2 with Flywheels on HS2

Exec Summary

Successful deployment of flywheel technology on SCS HS2 Euston site resulted in savings on an annual basis of over £39,000 as well as 55 tonnes of tailpipe CO2 emissions.

Technology Summary

Equipment like tower cranes, hoists and pumps is often used dynamically on construction sites. This means that the equipment requires a high power only for a short time (e.g. a tower crane lifting a load) while most of the time the power requirement is low (e.g. a tower crane slewing, lowering a load or waiting for the next job). Traditionally, the power source – a diesel generator, a mains connection or a chemical battery – have to be sized for the peak power. As a result, they are oversized which increases not only the rental or purchase cost but also reduces the efficiency which leads to higher
fuel usage which in turn wastes emissions.

Flybrid has developed a flywheel power system – called PUNCH Power 200 – that can inject energy at high power rates, quickly and exactly when required. As a result, the main power source can be sized much closer to the average power demand from the equipment, because the flywheel takes
care of the power spikes.

The flywheel system enables generators to be downsized by a factor of 2-3 and can significantly reduce the peak power demand on mains connections or chemical batteries by peak lopping the supply to critical equipment, which reduces costs & lead time.

This saves the construction customers tens of thousands of pounds per equipment per year, but also massively reduces waste & harmful emissions from construction sites.

Use Cases

The PUNCH Power 200 is typically deployed on applications with highly dynamic load cycles, most commonly (but not exclusively) those with large electric motors being run by diesel generators. Flybrid has experience using the system on cranes, hoists, pumps, welders, mixers, material handlers, mining equipment water treatment plants and many more.

In addition to reducing the financial & environmental cost of diesel generators, the flywheel system can be used to downsize HVO, LPG or hydrogen generators as well as mains connections and chemical batteries.

Trial and Results

On the Euston HS2 site, it was proven that the flywheel system enables a Terex CTL 430 tower crane to be powered by a 200kVA HVO generator instead of the traditionally specified 500kVA generator. This saved significant amounts of fuel costs and harmful emissions on site.

During a work package to test emissions, it was proven that the PUNCH Power 200 system enables the aftertreatment systems of Stage V generators to work efficiently. Running a 300kVA Stage V generator on its own at low power actually increased emissions compared to Stage III. The flywheel system enables a 100kVA Stage V generator to power the same equipment as a 300kVA generator. As the baseload of the 100kVA Stage V generator is higher, the aftertreatment system works efficiently and therefore emissions are significantly reduced while achieving a valuable fuel saving.

Finally, it was proven on the Euston site that the flywheel system can also be used in combination with plant that is powered by mains. Sites where available mains power is limited can use a PUNCH Power 200 to avoid deploying diesel generator which saves costs & reduces toxic emissions.

Cost and CO2 Savings

The trial concluded that using the PUNCH Power 200 to downsize a 500kVA generator to a 200kVA generator enabled net savings of £780 per week => £39,000 per year while reducing tailpipe CO2 emissions by more than 55 tonnes due to reduced HVO consumption.

Future Opportunities

Since the conclusion of this trial, PUNCH Flybrid has continued to expand. In 2022 the fleet of flywheel system saved over 1 million litres of diesel, and prevented nearly 2.7 million tonnes of CO2 emissions.

Applications range from tower cranes, hoists, lifts, concrete pumps, crushers, polymer piling rigs to welders and compressors.

Flywheel systems can be used to peak shave the loads demanded from diesel, gas or hydrogen generators, chemical batteries as well as mains connections. As a result, these main power sources can be significantly downsized. This not only reduces costs and emitted emissions during use, the downsizing also significantly reduces embedded emissions during manufacturing and recycling of the main power source.

Applying the flywheel system widely to the HS2 construction project can save the combined emissions of 20,000 cars every year, based on original project assumptions.