The role of the bus in reducing emissions


Yesterday's UK Bus Summit gave key industry professionals the time to examine why buses are an integral part of the solution to Clean Air Zones (CAZs) rather than the problem. The event gave speakers and delegates the opportunity to disseminate best practice and give all stakeholders the opportunity to exchange views as part of the consultation.

David Fowler reports on the first session below

Greener Journeys chief executive Claire Haigh kicked off session 1 of the UK Bus Summit 2018, held in London yesterday, on the role of the bus in reducing emissions. She welcomed transport minister Nusrat Ghani's enthusiastic support for buses as "wonderful".

Turning to the question of emissions, she said that on air quality, "we really are facing a public health emergency".

Modern pollutants were not visible like the smogs of the 1950s, but were "every bit as lethal".

Transport had a big burden of responsibility for tackling the problem, as the single biggest emitter of NOx.

"The sheer volume of traffic on our roads is not just a drag on the economy but a killer," she said. Cars were the biggest source of transport emissions (40%), followed by vans and HGVs, with buses on 6%.Tackling congestion should be a cornerstone of clean air policy and "should be targeted at the biggest polluters", she said.

Progress in bus technology had outstripped that of cars so that a Euro VI bus was cleaner than a Euro 6 car, even before taking into account the bus's extra carrying capacity. "Clean air zones need to embrace bus travel as an integral part," Ms Haigh argued. But current government guidance requires councils to target buses first, then HGVs, and cars as a last resort – "the exact reverse order".

"The Government has shied away from upsetting the car lobby," she said. "On this occasion the Government must show leadership. Passing responsibility for difficult decisions on to local government will not be sufficient." Clean air zones, she said, must encourage a shift from cars to bus – not just to reduce pollution but to bring about wider health benefits through encouraging active travel.

In the 1950s the Government rose to the challenge and passed the Clean Air Act to tackle smog. "No less is asked of our government today," Ms Haigh concluded.

Go-Ahead chief executive David Brown said that air and road space were both public goods, "but we're not good at sharing road space in a way that's fair".

Regarding cleaner technology, it had advanced in the bus sector, and Go-Ahead had converted its garage at Waterloo to all-electric operation.

But he said: "To see a real breakout of electric buses we need the technology and the supply chain to be on firmer ground."

For electric buses to be more widely introduced there need to be investment in infrastructure, including electrical supply infrastructure, and town planners would need to think differently, he said.

Converting a 100-bus garage to electrical operation was a bigger challenge than charging an electric car at home overnight.

He added that any pollution from transport was made worse by congestion. "Whatever tractive power you use, you get the lowest pollution when congestion is lowest." Buses are able to address both issues: they can reduce congestion and improve air quality.

Euro VI buses were a huge environmental advance, he said. But for electric buses to be widely adopted, there needed to be a reduction in the costs of investing in them.

If clean air policy forced out buses from town centres it would be "a massive own goal", forcing more people to use cars. The focus should be on the most effective use of road space.

"At times the public good outweighs the importance of the ability to use a car or make a delivery in one hour," he said. "With a disciplined approach to managing road space, there is a chance everyone will get what they need."

In her keynote address at the start of the conference transport minister Nusrat Ghani had announced the award of £40m to retrofit older buses with clean technology.

Even the oldest buses can be brought up to modern standards, as demonstrated by a video featuring Sir Peter Hendy, recounting how his 1962 Routemaster bus had successfully been fitted with a Euro VI Cummins engine.

Winfried Doelling, Twintec Baumot Group director of retrofit and aftermarket, argued that retrofitting pre-Euro VI buses with improved emission reduction equipment was "an important part of the solution" to air quality in cities. The Baumot Group specialises in retrofit and aftermarket solutions worldwide. A bus can be retrofitted for about £20,000, a factor of 12 to 15 cheaper than buying a new bus, and potentially, he said, allowing an entire fleet to be converted in the space of a year.

Baumot brings buses from Euro III to Euro V and EEV up to modern standards by replacing the entire exhaust and silencer system with its BNOx selective catalytic reduction system. The result is better than Euro VI standards for particulate matter and NOx reduction. The system is accredited under the Clean Vehicle Retrofit Accreditation Scheme and meets the requirements of the Millbrook London Transport Bus test cycle.

The system uses the standard AdBlue additive, but is uniquely optimised to operate from low engine temperatures. Applications are developed for specific bus types, Mr Doelling said, and manufactured to the standards of the original equipment.

Tests at Millbrook showed 99.8% reduction in NOx, below London's ultra low emission zone requirements.

Few cars meet the Euro 6 standard for NOx emissions of 80mg/km outside laboratory conditions. Fitted to a Euro V VW Passat 1.6, the BNOx system reduced NOx emissions from over 1,000mg/km to 69mg/km in real-world driving conditions. Emissions from a Euro V ADL Enviro 400 and Enviro 200 were reduced from figures in the thousands to 134 and 64mg/km respectively.