Bus and coach operators must cut emissions – and that could mean retrofitting cleaner technology. John Lewis reports
Bus and coach operators all over the UK are facing growing pressure from local authorities to cut diesel exhaust emissions. The big enemies so far as councils are concerned are nitrogen oxide (NOx), which includes nitrogen dioxide (NO2), and particulates – both of which are potentially damaging to public health.
Cutting their presence means meeting Euro 6. The problem is that disposing of Euro 5 vehicles earlier than originally planned and acquiring Euro 6-compliant models to replace them means major capital expenditure at a time of continued economic uncertainty. That of course presupposes that a decision hasn’t been taken to abandon diesel altogether and opt for electric, gas or hydrogen-fuelled vehicles instead. But why dispose of a Euro 5 or possibly older bus if it can be upgraded to Euro 6 by retrofitting the appropriate equipment? It is a route a growing number of fleets are pursuing – and several specialist manufacturers are only too eager to help them. [wlm_nonmember][…]
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Among those leading the charge is Eminox, with its well-established SCRT (Selective Catalytic Reduction Technology). The retrofit equipment typically employs a continuously-regenerating particulate trap plus selective catalytic reduction, which brings down NOx emissions using AdBlue. In 2017 it became the first system of its type to meet the requirements of the government’s Clean Vehicle Retrofit Accreditation Scheme (CVRAS) run by the Energy Saving Trust.
CVRAS certifies technology that complies with real-world Euro 6 emission levels. Most importantly, it signifies that it will meet the requirements likely to be imposed by the various low and ultra-low-emission zones due to be rolled out across the UK. CVRAS certification can be used to back applications for money from government initiatives that appear every so often with the aim of reducing pollution. These include the £30m Clean Bus Technology Fund for England and Wales that was announced in 2017, which is run by the Joint Air Quality Unit.
Summit talks
Speaking at the UK Bus Summit earlier this year, Transport Minister Nusrat Ghani said that the fund was being boosted to £40m immediately. Local authorities and related organisations were originally invited to apply for a share of the £30m now and for a slice of a further £10m in two years’ time. “However we received a large number of strong applications for this round and we wanted to start realising the air quality benefits as quickly as possible,” the minister said. “So we’ve made the full amount available now to support two-year projects.”
More than 2,700 buses will be retrofitted according to Environment Minister, Therese Coffey. The fund’s 20 beneficiaries so far include the West Yorkshire Combined Authority, Bristol City Council, Gateshead Metropolitan Borough Council, Leicester City Council and Transport for West Midlands. In March, Nusrat Ghani also announced the £48m Ultra-Low Emission Bus Scheme to help operators and local authorities put hundreds of brand new environmentally friendly buses on the road.
Eminox sensibly recognises that SCRT is not the only retrofit route to Euro 6 virtue that can be followed. The Gainsborough, Lincolnshire-based business has decided to forge close links with Danish company Amminex. The move means that it is now offering Amminex’s ASDS (Ammonia Storage and Delivery System) on this side of the North Sea alongside its own SCRT system.
So why offer both? ASDS uses ammonia held as a solid in removable and replaceable cartridges which are released into the exhaust system as a gas. Its big advantage, says Amminex, is that it works particularly well in the cold. Retrofit packages that depend on AdBlue sometimes fail to function as efficiently as they should at low exhaust temperatures – and temperatures can be low when a bus departs from its chilly garage first thing in the morning having been stationary all night. Evidence from operators suggests that ASDS functions effectively in conditions that are far icier than those usually encountered in the UK.
Cold comfort
Amminex cites data from a Transdev bus in Sweden, which appeared on a NOx Tracker Live app during one particularly bitter morning. “98% NOx reduction at -15°C wasn’t something we’d seen before,” said Amminex Chief Executive Officer, Annika Isaksson. “However it proves that ASDS doesn’t care whether it’s warm or cold outside,” she continued. “It just keeps dosing exactly the right amount of ammonia into the exhaust.”
55 Euro 5 buses operated in London by Metroline have had ASDS installed. One of the vehicles has been independently tested at Bedfordshire’s Millbrook Proving Ground, and the resulting data would appear to support the claims Amminex makes for its system. “From previous trials we knew that ASDS was doing a good job,” said Ian Foster, Metroline’s Engineering Director. “However it was quite a surprise to us when the official test results showed that the NOx emissions of a Euro 5 bus were cut to Euro 6 levels just by substituting ammonia for AdBlue.”
Baumot too is taking a different approach to controlling emissions, this time with something called BNOx. It makes use of AdBlue, but not by injecting it as a liquid. Instead, it uses hydrolysis and a small generator to produce ammonia gas from it and injects that into the exhaust. This means it can function effectively at low temperatures says the company. Returning to the topic of funding, Baumot points out that £1.6m has been allocated to Phase 1 of Transport Scotland’s BEAR (Bus Emissions Abatement Retrofit) programme. The money is available to bus operators located or running services in Edinburgh, Glasgow, Aberdeen and Dundee – all of which are scheduled to introduce Low Emission Zones – or in one of the country’s Air Quality Management Areas, it adds. The Energy Saving Trust administers the fund in line with Transport Scotland’s criteria.
Last autumn, Finland’s Proventia stated that its NOxBuster City retrofit package scored NOx and NO2 reductions of almost 99% according to independent tests carried out on a Euro 5 bus operating in Germany. It clearly impressed market research and management consultancy giant Frost & Sullivan; in January NOxBuster City received its Best Practices 2017 technology award. Proventia is represented in the UK by Excalibre.
London calling
The city placing the greatest emphasis on the need to make the atmosphere more breathable – and the need for bus operators to help – is without doubt London. Last year Mayor Sadiq Khan announced the launch of a Transport for London (TfL) retrofit initiative costing a hefty £86.1m to upgrade upwards of 50% of the capital’s buses to Euro 6. Around 5,000 vehicles are to be modernised, and the aim is to ensure that the capital’s entire fleet of buses complies with Euro 6 as a minimum by September 2020.
To clean up their act, pre-Euro 6 buses will be fitted with upgraded exhaust systems supplied by one of five suppliers appointed after a competitive tender process. They are Eminox, Amminex, Baumot, Proventia and HJS. The mayor’s initiative is among a wider clutch of policies which will include the implementation of the Central London Ultra Low Emission Zone (ULEZ) in April 2019. All London buses that enter the ULEZ will have to be electric, hydrogen or hybrid. The mayor’s ultimate aim is to phase out all diesel-only buses in the capital: “I am determined to take the bold action needed to protect the public from London’s poisonous, deadly air,” he stated.
Operators based outside London bringing passengers into the ULEZ will be able to continue to use diesels, but they will have to meet Euro 6. Eminox says that during the coming months they should start thinking about what they will need to do if their vehicles do not already comply, and make plans accordingly. Retrofitting diesels with emission reduction equipment in line with TfL’s requirements does not come cheap. It costs over £17,000 per bus on average, says Eminox, and a package such as SCRT can take approximately 50 man hours to install.
Further action
Sadiq Khan is also slowly rolling out Low Emission Bus Zones (LEBZs) in locations outside the planned ULEZ where air quality is particularly poor. Companies running buses in these areas will have to use vehicles that already match or go beyond Euro 6; the aim is to reduce damaging emissions by at least 84%. A dozen LEBZs will be in place by 2019, promises TfL, and two of them have already been introduced. A zone between Streatham and Brixton came into force last December, while the one that runs down Putney High Street made its presence felt just over a year ago. An area embracing the A12 Eastern Avenue was set to be introduced at the time of writing.
Admittedly it’s early days – but are the LEBZs that have already been implemented proving to be successful? Eminox believes they are. The Putney LEBZ has achieved a precipitous 90% decline in hourly pollution level breaches, it says, along with a 40% fall in annual NO2 concentrations. The firm has already upgraded upwards of 400 buses in line with LEBZ requirements.
A number of Bus Priority Schemes are included in the LEBZs. They are designed to give buses priority over other vehicles and not just to speed up journey times. If they keep moving rather than constantly grinding to a halt as a consequence of traffic congestion, then there will be fewer damaging emissions from idling engines. That also means that less fuel will be wasted. TfL intends to spend £50m on such schemes.
Sadiq Khan hasn’t finished yet; last November witnessed the launch of a consultation which could lead to the ULEZ coming into force London-wide – so far as buses, coaches and trucks are concerned – from October 26, 2020. Under this plan it would go on to affect the majority of cars, vans and motorcycles in an area encompassed by the North and South Circular Roads from October 25, 2021.
Engine of change
While retrofitting an exhaust emission control system is likely to be the option chosen by most affected operators of diesels, another solution could be to remove the existing engine and slot in a Euro 6 diesel instead. Not surprisingly it’s a choice favoured by Cummins, and it has repowered an AEC Routemaster to make its point. Take a Euro 4 engine out of a 2007-registered bus and install a Euro 6 diesel instead and you can reduce particulates by almost 90% and NOx by 50%, the engine manufacturer contends.
Elsewhere, politicians in a number of regional towns and cities will need to implement plans to make the air their constituents breathe less harmful. Published last July, the government’s Air Quality Plan highlighted the 29 English local authorities with the worst air pollution. It went on to instruct them to draw up action plans to deal with the problem. The final version of these plans must be published by the end of December.
The government’s preferred solution is the introduction of Clean Air Zones (CAZs) which are likely to result in diesels that fail to meet Euro 6 being penalised. Birmingham, Derby, Leeds, Nottingham and Southampton are expected to implement them by the end of 2019. Wales and Scotland are pursuing a similar policy to England’s. Cardiff should have a CAZ by 2021 and Glasgow will have its Low Emission Zone by the end of this year. Oxford is not one of the 29 councils on the government’s list, but is nevertheless planning to bring in a Zero Emission Zone beginning in 2020. Diesel and petrol vehicles will not be welcome but their electric counterparts will be.
Last year saw the announcement of a £220m Clean Air Fund which English councils will benefit from over the next year or so. Some of the cash could be used to retrofit buses with emissions reduction technology, suggests Eminox.
Global reach
The UK is by no means the only country taking radical steps to reduce bus and coach emissions. 28 air quality regions embracing over 60 municipalities have been set up in Germany, says Eminox, and are mandated to cut atmospheric pollution. As part of this initiative the German government has committed €150m as part of its €1bn Clean Air 2017-20 programme, which will be used to upgrade city buses using retrofit technology. As a consequence, Eminox has joined forces with German diesel particulate filter specialist Puritech to deliver suitable equipment. “The combined efforts of both Puritech and Eminox will provide an efficient solution to the challenge of reducing city bus pollution across Germany,” said Eminox Retrofit Sales Director, Carlos Vicente. The additional business generated by the need to cut emissions is prompting Eminox to take on more apprentices. Nor is it the only firm in the sector growing; HJS is about to expand its UK facility. Proventia President and Chief Executive Officer, Jari Lotvonen, makes the point that cutting emissions using retrofit equipment is not an activity that has to be confined to Europe. “We’re also looking for opportunities in Asian markets,” he stated. “South Korea in particular is important to us and we’re currently testing NOxBuster City in Seoul.”
It serves to underline a point that cannot be ignored. Air pollution is a global problem – and it is one that every country must address sooner rather than later.
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