Retrofitting Buses: The fast route to cleaner air and electrification

Bradley Fox from Zenobē discusses the benefits of retrofitting buses as an economic and environmental alternative to investing in new ones.

Electric buses are rapidly making their mark across the UK. In 2023, zero-emission buses (ZEB) accounted for 45.1% of all new large bus registrations, a 69.3% rise from 2022. Britain also registered 1,314 new e-buses, the most in Europe with second placed Germany lagging behind on 835.

However, despite the strong ambition to transition to net-zero fleets in communities across the UK, a significant challenge remains. Old diesel buses will linger on our streets well into the next decade unless we develop solutions that make it easy for operators to decarbonise their fleets.

Buses represented 62% of ticketed public transport journeys in Britain in 2022, so if we are to improve our air quality then prioritising their electrification is essential.

So, what are the solutions to this problem? In this article we’ll look at a specialist option: electric retrofitting or ‘repowering’, how it works and why collaborating with a fleet electrification partner can make the switch to an electric fleet much easier for operators.

Problem solving through partnership

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Electric retrofitting is one solution for bus operators looking to electrify their fleets today. The process involves replacing the diesel power systems in traditional buses with electric ones, breathing new, environmentally-friendly life into old vehicles at a fraction of the cost of a new electric bus.

At Zenobē, we’ve been working with Big Bus Tours, a hop-on, hop-off open-top bus company based in London. We’ve financed the electrification of their fleet through retrofitting, with the process being carried out by leading engineering specialists Equipmake.

As well as funding the retrofit process, we’re also providing a Power Purchase Agreement (PPA) that enables Big Bus to be more proactive and agile in managing their energy costs. So far ten diesel buses have already been repowered, with a further ten set to hit the road later this year.

Cleaner, faster delivery

Electric retrofitting delivers sustainable benefits right from the start. By repurposing existing buses, the industry can avoid waste, preserve vital resources and reduce landfill. This is something we carefully consider in all our projects, with our EV bus batteries being repurposed in second life applications to reduce the environmental impact of the battery supply chain.

Electrifying buses eliminates the tailpipe emissions produced by diesel engines. According to First Bus, each retrofit can reduce air pollutants and harmful emissions by up to 95%, significantly enhancing urban air quality and aiding operators in meeting the UK’s low emissions targets.

Beyond the health benefits of cleaner air, which include reduced asthma rates and improved mental health, a 2020 study by CBI Economics demonstrated that better air quality could inject millions of pounds into local economies. This financial boost comes from saving lives and reducing illnesses and work absences due to nitrogen dioxide (NO₂) exposure.

Retrofitting buses accelerates fleet electrification in cities. Repowered vehicles can be up to 50% cheaper than new electrics and the driveline can be installed in between four and eight weeks, depending on the vehicle type – that’s compared to a 12-month lead time for a new electric vehicle. This quick turnaround allows for the roll out electric buses faster and at a lower cost, thereby reaping the benefits of reduced air pollution sooner.

Now is the moment

With the new Labour government in power, there is a strong commitment to achieving ambitious emission reduction targets across both energy and transport.

The benefits of repowering are obvious: tailpipe emissions are slashed from day one, the turnaround time for zero-emission transport is quicker, vital resources are saved and waste is reduced. Operators looking to electrify should certainly consider repowering as an option.

While retrofitting isn’t a silver bullet for reducing urban pollution, it plays a vital role alongside other policies such as increased renewable energy use and schemes to encourage people to take public transport. Together, these steps can make our cities cleaner, quieter and emission-free sooner than we imagine.

Zenobē is an EV fleet and grid-scale battery storage specialist, headquartered in the UK. www.zenobe.com