Four diesel alternatives for buses are available so far, and very soon First UK Bus will have all of them carrying passengers in anger and helping the group to harvest data on the operational pros and cons
The uptake of alternative energy sources in double-decker buses received a boost over the last fortnight thanks to First, which has scored two debuts for a big group.
In Bristol, it has taken delivery of its first wholly-owned biogas-fuelled double-decker, while in York on Monday (14 August) it became the first operator to place the battery-powered Optare Metrodecker EV demonstrator into service, on park-and-ride duties.
Both are significant milestones. Each bus is cleaner at the point of use than a Euro 6 diesel.
While biogas and electric are poles apart in their application, when combined with developments elsewhere, their use in service may signal that the groups are beginning their tentative steps towards alternative power sources in double-deckers.
As yet, First has ordered no further gas buses, while completion of a deal for electric double-deckers for York is awaited.
The group is already committed to three of the latter in 2018, but that number may increase if further funding is secured. Coupled with emission specifications for Bristol’s MetroBus bus rapid transit scheme, it’s unlikely to be long before First has its name on an order for more alternative power ‘deckers.
Complementing these developments is the group’s on-going experience with hydrogen fuel cells in Aberdeen, and pockets of hybrid operation. Together, those place it among the leaders in the evaluation of alternative technologies.
UK Bus MD Giles Fearnley says that the opportunity to get in-service feedback on all energy sources is welcome. While any large-scale move away from diesel is still a long way off, encountering and dealing with teething problems now is a valuable lesson for the future.
Life’s a gas in Bristol
In Bristol, First’s debut gas double-decker is a Scania N 280 UD with Alexander Dennis Enviro400 City bodywork.
It was launched last Tuesday (8 August) and is described by First West of England Regional MD James Freeman as “a pathfinder vehicle” for the group.
“Double-deckers are key in Bristol and the purchase of this bus is to ensure that First is comfortable with biogas. I am personally, but we want to demonstrate to stakeholders that it is a sensible approach,” he says.
“The authorities here are very concerned about air quality. It is a bohemian city with lots of awareness of environmental aspects, and Bristol City Council looks at buses’ contribution as a critical matter.”
The pilot bus is one of 25 ADL-bodied Scania double-deckers that will enter service in Bristol.
Initially the whole batch was slated to be diesels, but the specification for a single chassis was changed to gas power to allow First to demonstrate the concept’s capabilities. It also gained a City body with some non-standard items for a bus delivered to the group.
Gas has debuted in Bristol for a reason, adds James. “It satisfies the minimum emissions specifications for Metrobus. Euro 6 diesel does not, although it has a two-year derogation,” he says.
“Hybrid and the zero-emission technologies also comply, but the key is that not only can we make an excellent impression with gas power, we can also afford to do it without external funding. It stacks up commercially.”
That viability for biogas extends to the fuelling station, says James. “The business case is very important. If we are to go with a fleet of gas buses in the long term, I’m interested to see what we can do to spread the infrastructure costs further.
“I have visited Augsburg in Germany, where the gas fuelling station in the bus depot there is used during the day by other vehicles, including taxis and municipal vehicles.”
The hardware: A Scania ADL green machine
First’s gas double-decker is similar in specification to those in the process of delivery to Nottingham City Transport.
It has 70 seats and it is fuelled by what James describes as “a scaled down” station that has been supplied by the Gas Bus Alliance and is connected to the on-site gas main at Lawrence Hill depot.
The station has a compressor and gas storage bottles, and it holds enough to fill the ‘pathfinder’ vehicle.
The first vehicle order for MetroBus is expected to be placed within the coming months, says James. While he cannot yet confirm for certain what energy source these buses will use, he offers some pointers on each alternative technology’s viability.
“Fuel cells remain on another level altogether cost-wise, and I’m not sure that we would feel confident with hydrogen. It’s a big step from anything that is otherwise available.
“Likewise, electric buses are not yet commercially viable and we would be unable to invest in them without third party assistance. Hybrid is also an expensive technology, and our experience with it has not been brilliant.
“That is why gas is so attractive. A commercial undertaking can invest in it and be confident that it will deliver. There is also the option to cascade gas buses to other work later in life.”
Optare’s electric dreams
On York Park-and-Ride services, circumstances are different to MetroBus in Bristol and they suit battery power well.
Electric is already an accepted part of the operation in the form of a batch of Optare Versa EVs, and the Metrodecker EV – with a substantially better range and carrying capacity than the single-deckers – is a natural progression.
Optare continues to develop the Metrodecker EV. In ideal circumstances it can now deliver a range of almost 150 miles between charges, and Commercial Director Robert Drewery says that utilisation of alternative battery chemistries will improve that further.
“At the moment the Metrodecker EV’s batteries can store 200kW/h of electricity, but the goal for 2018 is to increase that to 300kW/h.” Developments in the electric car industry are also set to benefit buses as battery technology advances while also becoming cheaper.
“The cost of each kW/h of storage has reduced hugely over the past three years. In the case of the Metrodecker EV, that has helped to bring whole-life costs into line with those of a comparable diesel thanks to its much lower energy costs,” he adds.
“There will also be a larger political mandate for zero-emission buses in the future. While we will build the Metrodecker in diesel form, we see a significant opportunity for the EV.”
Politics in play already
The political landscape is already relevant in York. The Metrodecker EV demonstrator – which was converted from the first diesel bus that debuted in 2014 – will stay in the city for a month, and it will be used on both the park-and-ride network and conventional city services.
Then it will move to First’s operation in Leeds, and Giles says that one of the reasons for doing that is to give experience of electric in more testing terrain.
York has little in the way of hills, but Leeds is the opposite. Operation of hybrid buses there has demonstrated that even when driven carefully and with regeneration in mind, hills can have just as significant an impact on their efficiency as they do on a conventional diesel’s.
“Our hybrid buses have sometimes struggled in Leeds, although we accept that understanding alternative technologies is always a learning process,” he says.
“The concept of a zero-emission double-decker is a wonderful one, and the key now is to gain practical experience of it.”
Commercial impetus
One thing that Giles says is key for manufacturers of electric buses is for them to make the product commercially viable.
At the moment, biogas is the only one of the four alternatives to diesel that can lay that claim, but Optare is confident that the Metrodecker will soon tick that box.
“Costs will definitely continue to come down and we see operators setting us the challenge of commercialising the Metrodecker EV,” says Robert. “The new battery chemistries will help in doing that and we are also working to make its electric heating system more efficient.”
At the moment, electric propulsion is precluded in most scenarios because of its high initial cost. Gas is, as James says, viable on its own merits, but one senior industry executive has reported that some local authorities already wish to direct the focus towards zero-emission, rather than low-emission, solutions.
As shown by First’s ongoing work to examine, investigate and refine new alternative power sources in Aberdeen, Bristol and York, there is unlikely to be a single answer to the air quality question.
But by driving manufacturers hard to further improve their offerings, the group is one of a select number of operators that can legitimately say that they are helping to shape the bus industry’s vehicles of tomorrow.
