One of the UK’s most significant bus orders for some time made its public debut on Friday 19 May when the first of 53 biogas-fuelled Scania N 280 UDs with Alexander Dennis Enviro400CBG City bodywork for Nottingham City Transport (NCT) were displayed in the city’s Old Market Square.
Described by NCT as “the greenest buses on the road,” they are part of a £17m investment, £4.4m of which has come from the Office for Low Emission Vehicles (OLEV).
The headline is that NCT’s buses represent the world’s largest fleet of biogas-fuelled double-deckers.
Data provided by Low Carbon Vehicle Partnership shows that each Enviro400CBG produces 84% less CO2 equivalent than a Euro 5 diesel bus, but that’s not the only reason to go with biogas.
“We believe that biogas is a better bet at Euro 6 than diesel,” says NCT Commercial Manager David Astill, who adds that the operator is sticking to the commitment that it made last year to buy no more diesel buses.
The 53 biogas double-deckers will replace the same number of Euro 3 diesels, but NCT makes little secret of its aspiration to more.
The Enviro400CBGs are the first Euro 6 buses in NCT’s 331-strong fleet. Nottingham is one of six cities that will become Clean Air Zones from 2020 and that’s likely to mandate Euro 6 compliance, leaving NCT with lots to do in the meantime.
“We would like to have 120 biogas double-deckers, and we hope that there will be another round of OLEV funding to assist us with that,” says Mr Astill. “But we don’t rule out buying more without external support.”
NCT’s commitment to buying no further diesel buses doesn’t necessarily mean that biogas will have everything its way, however. Mr Astill says that electric, hydrogen fuel cell or other alternative forms of propulsion could be utilised. But for now, biogas’ stock is high – and not just for NCT.
Swedish confidence in biogas
Scania’s low carbon strategy in the UK centres on biogas, and it has customised NCT’s Enviro400CBGs slightly at the operator’s request.
Chief among the changes is a range increase to 250 miles. That has been accomplished by increasing the pressure at which gas is stored on the bus to 250bar, something that is only available on buses with the City variant of the Enviro400 body; MMC models stay at 200bar.
“On the City, all of the tanks are at the rear of the upper deck and they are from a different manufacturer than those on the MMC,” says Bus and Coach Fleet Sales Manager Mark Oliver.
That allows storage of 1,030 litres of gas on the City against 750 litres on the MMC and that increase is gained by fuelling at 300bar against 250bar respectively.
“We believe that the predicted range of 250 miles will be accurate.
Prior to delivery of five Enviro400CBGs to Reading Buses we expected fuel consumption to be 2km/kg, and that was exactly what in-service trials returned,” adds Mr Oliver.
Get up and go: Four-minute refuelling
Fuelling equipment at Parliament Street has been supplied by Roadgas. Each bus will be replenished in four minutes, and four pumps – each with two hoses – will be installed when the project is complete.
“We have already provisioned the fuelling station for 200 buses in terms of space claim, the gas main and power supply,” says Roadgas Manager Jon Harman. Mr Harman explains that the existing plant has three compressors; as a modular set-up, that can increase to six.
Fillers on NCT’s Enviro400CBGs are mounted at the offside rear – an alteration requested by the operator – and the fuelling mechanism includes a ‘fusible plug’ safety element should the bus be moved while the hose is still connected.
Similar to an air connector between a lorry and a trailer, it is designed to give way when stressed, and it incorporates a shut-off valve to prevent any leakage.
Biogas is ready for take-off in Nottingham
Mr Astill explains that the buses – which at 11.4m seat 72 and come in unladen at a shade under 12 tonnes – will start to enter service in mid-June.
30 are scheduled for delivery this year, with the remainder coming in 2018. Most will carry colour-coded liveries for specific routes, and NCT chose the City body to differentiate the biogas buses from its existing diesels.
Given the excellent turn-out at Friday’s launch, the operator’s new double-deckers are catching the public’s eye already. Time will tell whether the rest of the industry responds in the same manner – but things have never looked more promising for biogas.
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Scania has made no secret of its belief that a double-deck chassis unlocks biogas for many operators. The major deal with NCT, respected as one of the UK’s finest operators, also gives the concept another major shot in the arm follows the gas ‘decker’s launch with Reading Buses.
As prime contractor on the NCT order, Scania also has its ducks in a line to supply and back the Enviro400CBG. Repair and maintenance contracts are available, and in a brave move it has committed to supplying biogas double-deckers on operating lease if desired.
Mr Oliver says that interest in Scania buses is already split equally between diesel and biogas versions. With Clean Air Zones likely to spread in coming years, simple yet highly-effective gas technology looks set to spread. This may just be the start for the Enviro400CBG.
