Complying with central government policy relating to Clear Air Zones meant developing a long-term sustainability plan for Nottingham City Transport, which settled on biogas as its fuel of choice to do that
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With environmental concerns riding higher on the public agenda than ever before, the UK is one of 17 European nations currently taking action to improve air quality in order to reduce pollution and health impacts.
The government body charged with overseeing that programme is the Department for the Environment, Food and Rural Affairs (DEFRA).
Following a 40-day consultation, and further informed by a series of roundtable discussions with relevant industries and interest groups, DEFRA identified five UK city centres – Birmingham, Derby, Leeds, Nottingham and Southampton – where older and more polluting vehicles would be discouraged from entering by 2020.
Alleviating the problem
With a population of 300,000, which increases to in excess of 1.5m in the wider metropolitan area, the city of Nottingham relies on its local authority-owned bus company, Nottingham City Transport (NCT), to do all that it can to help alleviate the problem.
Led by Managing Director Mark Fowles, the company has long had a reputation for innovation, including pioneering the use of alternative fuels in urban bus operations. The latest incarnation of that is dedicated gas power.
Representing an investment of £17m, including a £4.4m Low Emission Vehicle grant from the government-funded Office for Low Emission Vehicles (OLEV), a total of 53 Scania/Alexander Dennis (ADL) dedicated gas-fuelled double-decker buses will have been introduced into service by the end of 2018.
£2m of the headline figure has been invested into an on-site gas fuelling station at NCT’s Lower Parliament Street garage. The facility is available not only to refuel NCT’s buses, but is also open to third parties that run vehicles fuelled by gas. “By investing in this fleet of gas-fuelled double-deckers, we are acquiring a sustainable solution that will deliver substantial environmental benefits over the coming years,” says Mark.
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“Compared to the Euro 3 buses that they are replacing, we are expecting significant environmental improvements. Independent tests have confirmed an 84% well-to-wheel saving when comparing biogas operation to Euro 5 diesel, and we are confident that these anticipated returns will be turned into reality.”
As a forward-looking operator, NCT had its plans for the future mapped out ahead of the DEFRA report’s publication.
“We began this project back in 2012,” says Mark. “By 2014 we had scoped out our requirements. We conducted extensive research into alternative fuels and concluded that biogas offers an outstanding long-term sustainable solution.
“We entered into discussions with Scania, our long-term heavy-duty bus supply partner, and explained that we wanted a gas-fuelled double-decker. Our fleet today is overwhelmingly double-deck, so that was a key requirement.
“Scania came to the party, as did ADL, one of our key bodywork providers, and the resulting Scania/ADL vehicle is an excellent, premium-quality product of which we are all extremely proud.”
Refuelling capabilities
The on-site gas filling station means that NCT has a gas bus refuelling capability very similar to that of its diesel buses. That is a major advantage in operational terms as it allows the gas buses to be scheduled and operated smoothly alongside their diesel counterparts.
Moreover, no special provision such as the plug-in points required by electric buses are necessary, meaning that the gas double-deckers also offer a logistical advantage in that they can be placed among NCT’s diesel vehicles in the depot overnight.
To ensure that its investment in a gas refuelling station is future-proofed, NCT has sized the infrastructure to be able to handle 60-80 double-deckers a day currently, with plenty of in-built scope for future expansion.
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The facility has a total of four gas dispensers, three of which are inside the depot building. The fourth, which will accommodate third party vehicles, is located outside by the filling station.
Meeting the needs
Regarding the gas-powered fleet – the world’s largest ever order for gas-fuelled double-deckers – NCT worked closely with Scania and ADL to develop a bus that would meet its operational requirements
The operator was looking for a minimum range of 250 miles to cover more than 95% of its daily duties on a single fill. To achieve that, Scania and ADL developed a 250bar solution, with gas stored on-bus in two 515-litre tanks mounted horizontally above the engine.
Capacity details
Although high in capacity, this arrangement does not impact on the passenger space. The resulting vehicle can accommodate 84 people, 72 of which are seated. There is also an area for wheelchair users and buggies.
In terms of overall length, the buses are 11.5m long, which is midway between NCT’s existing 10.9m and 12m double-deckers. The operator reports that driver acceptance is good in every respect. Its entire large bus fleet is Scania, so drivers are already familiar with the layout in principle. Improvements made to the cab in the new vehicles have also gone down very well.
Sustainable future
“The introduction of these vehicles is an important move for us,” says Mark. “In order to meet our obligations under the government’s Clean Air Zone policy, it would not have been possible to have a limited number of low emission buses; we need to move substantially, almost exclusively, to gas for our larger vehicles.
“Our intention is to have 120-plus biogas-fuelled buses in service by 2020 out of a heavy-duty fleet of 300. That is a step change in terms of environmental performance.
“Our ultimate aim is to deliver the same quality of service throughout our area, and you can expect to see more of the same in the future as we continue the transition to a more sustainable transport system for Nottingham.”
