The Ballymena-based manufacturer has become the first OEM in the bus sector to launch a diesel to battery-electric repower solution for customers

First Bus Streetdecks under conversion at the NewPower facility

There’s no doubt the electric bus revolution is in full swing, but for some years many have tried (and more often than not failed) to convert conventional diesel or diesel-hybrid buses into fully electric vehicles.

Names like Magtec and Equipmake have tried to make inroads into what could potentially be a very lucrative market. Indeed, earlier this month, the latter company signed a deal with London open-top sightseeing outfit Golden Tours to repower 10 more Volvo double deckers using its Zero-Emission Drivetrain technology.

However, these fringe players lack the robust reputation of the mainstream bus manufacturers. Now, that looks set to change with the arrival of NewPower, what the press release calls a “bold new enterprise designed to replace older diesel engines with new zero-emission electric powertrains”, from Ballymena-based bus builder Wrightbus.

New start for NewPower

Wrightbus chief executive Jean-Marc Gales cheerfully admits with effervescent Gallic charm that the idea for NewPower came about following a rather terse conversation with one of those upstart repower specialists. It seems they had the temerity to ask whether the manufacturer would stand by its existing warranty offer if the repower specialist started “drilling holes into the chassis and structure of the bus” to shoehorn their battery-electric driveline into a Wrightbus vehicle. Gales left me with little doubt that they received (very) short shrift.

But it set the former Lotus boss thinking, especially when over 30,000 diesel buses in the UK will need to be replaced by zero-emission alternatives within the next decade or so. Whoever forms the new government will also likely face spending constraints, so perhaps the government schemes that have provided the bulk of funding for new zero-emission buses in Britain will feel the purse strings tighten. Gales, therefore, believes there is a massive opportunity to convert existing diesel buses to battery-electric. Hence, the decision to launch NewPower, making Wrightbus the first OEM in the bus sector to bring a repower solution to market.

There is a huge market of mid-life buses which, once converted, can have an immediate impact on helping to improve air quality in towns and cities up and down the UK

“While we are selling new hydrogen and battery-electric buses all over the world there is a huge market of mid-life buses which, once converted, can have an immediate impact on helping to improve air quality in towns and cities up and down the UK,” said Gales. “We have long been recognised as the world-leading manufacturer of both hydrogen and battery-electric buses and now NewPower will add another string to our bow.”

Serious investment Wrightbus is putting some serious money into NewPower, which is based in a new 45,000sq ft facility at Bicester in Oxfordshire. In a previous life, the modern building on a business park on the edge of the town was planned to be one of the ‘microfactories’ of doomed electric vehicle manufacturer Arrival. While much of the engineering legwork has been undertaken by Wrightbus in Ballymena, NewPower has added to its team, with senior figures in the venture joining from Land Rover Special Vehicle Operations, BMW and McLaren. Among them is programme director Graham Hamlyn, who joined the business from Switch Mobility but previously spent a decade with Aston Martin. While 22 jobs were initially created – split between production and office staff – it’s predicted that 65 will be on-site at Bicester by the end of the year.

NewPower roll-out

To begin with, Wrightbus is focusing its NewPower efforts on its Streetdeck double decker model. It then plans to move on to other Wrightbus products such as the Gemini 2 double decker. That process could include London’s New Routemaster too, where the manufacturer has offered fleet owner Transport for London a battery-electric repower solution. Gales candidly revealed that talks with TfL on just such a conversion have been ongoing for the last 18 months, which could explain why TfL recently decided to scale back the midlife refurbishment programme for the ‘Boris Bus’ fleet that’s currently underway. 

Ultimately, there are plans to engineer solutions for products from other manufacturers. This could include continental Europe, where Wrightbus’s hydrogen fuel cell buses have gained ground in the German market. Gales hinted that the manufacturer’s new support facility in Cologne could play a role in these aspirations.

The total engineering investment is estimated to be around £1m per bus model, with each repower priced at around £200,000 – this represents a significant saving on the cost of a new battery-electric bus. Wrightbus is coy on numbers but claims it has firm orders for 40 conversions and hopes for 300 next year. Several Streetdecks from First Bus fleets in the Midlands, West Yorkshire and the West of England were in evidence at the Bicester facility last week.

Repower details

The conversion process takes around 11 days to complete. NewPower sister company All Service One – which handles Wrightbus’s fleet support operations – kicks off the process by inspecting the vehicle and then begins the stripout process, which removes the engine, gearbox, fuel tank, radiator, and other parts. These parts are returned to the customer for reuse. NewPower technicians then get to work installing the batteries and Voith Electric Drive System. The conversion process uses the existing differential and axle with the batteries and drive system mounted on a skid in the old engine bay for easy access.

Wrightbus offers customers a choice between two battery options. The first option, a 308kWh variant, comprises four Forsee Power Zen NMC 77kWh battery backs installed in the old engine bay. The second option, a 385kWh variant, includes a fifth battery back installed over the front nearside wheel arch. The latter’s installation process necessitates relocating the side destination display from the top of the first nearside window to a new housing within the new battery bay, but as Hamlyn points out, this enhances driver visibility.

However, the conversion process has some drawbacks, namely the loss of the downstairs rear saloon window to accommodate the Grayson HVAC system that keeps the batteries cool. There is also some loss of passenger capacity – a 73-seat diesel Streetdeck translates into a 68-seater with the 308 kWh and 385 kWh options. Standees drop from 22 passengers to 21 and 15 respectively.

A year ago, we had 200 zero-emission buses on the road. Today, we have over 900, and in the next year, we will get to 2,000. No one else comes close

Charging is accomplished via standard Combined Charging System (CCS) ports. First Bus has chosen to install a single 150kW CCS connector at the offside rear of its repowered vehicles, but Wrightbus says customers can specify ports on both sides of the vehicles if required. A full recharge takes around two hours, and that translates into a range of around 150 or 180 miles – a slight penalty on that offered by the newbuild Wrightbus Electroliner battery-electric double decker .

After crunching the numbers, Wrightbus expects that over a typical 17-year life, the Total Cost of Ownership (TCO) of a Streetdeck converted from diesel to battery-electric power at seven years old returns a TCO on parity with a new Euro 6 diesel bus. Maintenance costs are reduced by 41% and energy costs by 17%.

“We believe we are the number one zero-emissions bus maker in the UK,” said a bullish Gales. “A year ago, we had 200 zero-emission buses on the road. Today, we have over 900, and in the next year, we will get to 2,000. No one else comes close.”

This article appears in the latest issue of Passenger Transport.

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