Burning methane (natural gas) as an alternative to diesel to power heavy trucks can reduce carbon emissions by around 16% - but switching to biomethane produces even more dramatic reductions of up to 65%. But if biomethane is to become a viable mainstream alternative to diesel for road transport there are still many hurdles to overcome, as a conference held in London in June this year heard.
Opening the event, transport minister Norman Baker MP said that 20% of UK transport greenhouse gas emissions came from the HGV parc, and 70% of those emissions were from long haul heavy trucks. “Alternative fuels provide real reductions in emissions,” he said. “Biomethane also avoids the use of land for bio crops.”
Biomethane is usually produced from food, sewage and other organic waste by a process of anaerobic digestion, rather than from crops grown specifically to make transport fuel. This latter method is controversial as it can reduce food production at a time when the world’s population continues to expand.
While a number of bus companies have moved to gas power, most LGV operators have been reluctant to invest in gas or dual fuel vehicles (those that burn a mixture of gas and diesel) because of the lack of gas refuelling stations. Because buses are on fixed routes and come back to base every night it is viable for operators to install a dedicated refuelling station for their own fleet. While some LGV operators, such as those running secondary distribution operations with large numbers of vehicles based at a home DC, are in a similar position, tramping hauliers need to know they can refuel their trucks when away from base.
Equally, gas suppliers are reluctant to invest in refuelling stations while there is not a critical mass of vehicles to make use of them.
Impasse
To help break this impasse, the government has allocated £11m to a Technology Strategy Board project to run 13 trials of gas-powered LGVs and installation of refuelling stations open to any operator (see panel).
“Biomethane offers the highest C02 emissions savings - there are barriers but we are trying to tackle them. The refuelling infrastructure is reactively sparse and we are keen to expand it,” said Baker. “The Gas Hub is launched today and Gasrec has just opened the first of a planned network of gas stations that would be a step change in refuelling facilities.”
The Gas Hub is a web-based database of gas refuelling stations owned by fuel suppliers like Gasrec and by operators that are open for all vehicles. The hub is managed by Ciara Longman, lead air quality officer at the Royal Borough of Greenwich, and already lists over 30 liquid and compressed natural gas refuelling stations.
Just before the conference, Gasrec announced it was to open a multi-user gas refuelling station at the Daventry international rail freight terminal (Dirft) capable of handling up to 700 compressed or liquid natural gas trucks a days. It plans to open another multi-user site in the middle of 2014.
Gasrec is a producer and supplier of Bio-LNG, a blend of liquid biomethane (LBM) and LNG that it claims “combines the carbon and pollution reductions of LBM with the cost competitiveness and widespread availability of LNG”.
Chris Nash, chairman of Gasrec, said the company had built 13 gas stations in the UK since 2009, many of which were dedicated to specific operators. “We make Bio-LNG, truck it and operate fuelling stations,” said Nash. “It is down to the operators – we make it available but they have to buy it.”
Gasrec counts major operators such as Tesco, Kuehne+Nagel, Sainsbury’s, Stobart, Coca Cola, B&Q and DHL among its customers. “Dual fuel is becoming the cornerstone in the CO2 reduction plans of a few operators,” Nash said. “Many operators have their own fuel stations but are now asking for multi-user sites on major routes.”
Charlotte Morton, chief executive of the Anaerobic Digestion and Biogas Association (ADBA), said there was a lot of demand for biomethane, which is produced by digesting organic waste to make biogas (a mix of 40% methane and 60% CO2) and then removing the CO2.
“Biogas is a finite resource,” she stated, “but there are many benefits from using it in transport.”
Potential capacity
She put total potential UK biogas production capacity at 40TWh – around 10% of total domestic gas supply. “The tricky question is: How much is available for transport?” she said. Using a “back of the envelope” calculation she estimated the figure at around 28TWh – enough to fuel 150,000 heavy trucks.
But at present most biogas goes into the energy sector because of the government’s incentives to encourage the take up of low carbon fuel sources by the utilities. “We need more work to get biomethane into transport, using the renewable transport fuel obligation [RTFO] and energy equivalence,” she argued. Transport minister Norman Baker had however ruled out any immediate amendments to the RTFO and Morton quipped that chancellor George Osborne does not even believe climate change is happening.
Andrew Whittles, MD of Low Emission Strategies and chair of ADBA’s transport working group, said that attempts to use gas to power trucks 20 years ago had foundered on problems with ‘wet’ gas – methane mixed with other heavier gases such as propane and butane.
“In 2006 there were no vehicles, few plants outside the sewage sector and the transport industry had retreated to diesel,” he said. “But in 20 years we have not found a way to control NOx emissions from diesel vehicles. Now carbon emissions are on the agenda and we need an 80% reduction by 2050 - biogas can play a significant role.”
As well as lowering carbon emissions, burning gas is currently much cheaper than diesel – though maintaining this price differential depends on future government policy on fuel duty as well as the price of gas.
“There has been a lack of national policy – but this is starting to change,” said Whittles. “But there will be a finite supply of biomethane and there won’t be enough to cover all requirements. Now most goes to electricity generation or heating because the incentives are greater than for transport.”
Cleaner
And while the latest Euro-6 trucks are much cleaner than their predecessors in terms of NOx and particulate emissions, gas vehicles are cleaner still. With the UK facing infraction proceedings by the European Union (EU) for failing to meet statutory air quality standards (40 out of 43 local authorities were in breach of EU nitrogen dioxide limits in 2010) the government is supporting the development of gas-powered urban buses. Proponents of gas trucks would also like to see their use in cities encouraged by exemptions from congestion charges and other tolls.
Andy Eastlake, MD of the Low Carbon Vehicle Partnership, said HGVs accounted for 21% of UK surface transport carbon emissions in 2011 (compared with 58% from cars), up from 20% in 2010. Of these emissions, 45% came from long haul, 25% from regional distribution and 10% from urban deliveries.
For long haul and regional distribution Eastlake said there were “limited options” to reduce carbon emissions and gas or dual fuel offered “by far the greatest opportunities”.
“There is a potential prize of a 60% cut if we do everything possible on gas,” he said.
The 60% ‘well to wheel’ cut is achievable with full gas-powered trucks burning biomethane; this figure falls to 33% for dual fuel vehicles running on this green fuel and between 5% and 16% for trucks burning ordinary natural gas.
These potential savings compare with around 10% by making diesel vehicles as fuel efficient as possible or 8% by introducing diesel/electric hybrids or full electric vehicles on urban deliveries.
Eastlake reported that Coca-Cola Enterprise’s “very sound trial” of gas vehicles in 2011 had produced excellent results, including a 97% reduction in particulate emissions, a 60% cut in carbon dioxide emissions and 12% saving in fuel costs. As a result the operator had invested in 14 biomethane trucks and a refuelling station.
But he added: “Trucks use a lot of energy – let’s be realistic about what is achievable. The source of gas makes a huge difference to the carbon footprint and the supply of biomethane is still a challenge.”
He also pointed out that while gas and dual fuel engines are very clean in terms of NOx and particulate emissions and so help improve local air quality as well as reducing carbon emissions, all current comparisons have been with Euro-5 or earlier standards rather than the new Euro-6 vehicles.
“Diesel is not standing still and Euro-6 are extremely clean engines,” he said. “We must compare gas vehicles with them not with Euro-3 or even Euro-5.”
Key area
Eastlake also warned that while gas technology now had broad support from government, truck makers and operators, it must not “rely on handouts” as previous attempts to subsidise take up of LPG had failed.
The DfT’s 2012 Low Emission HGV Task Force produced by Ricardo and AEA had identified gas as a key area for significant carbon reductions for long distance transport, and a government gas strategy was expected by the end of this year, according to Rachael Dillon, climate change policy manager at the FTA.
“Biomethane is the only viable sustainable low carbon fuel for road transport,” she asserted.
The FTA’s Manifesto for Gas calls upon the government to guarantee that the current fuel duty differential between diesel and gas would remain for 10 years, derogations on vehicle weights and dimension limits to allow for new tanks and equipment and support for the development of public gas refuelling stations on main motorway routes. Dillon said that for fleets of more than 50 trucks, it was worth installing operators installing their own refuelling stations, but for smaller operators a network of 20 public refuelling stations as required if they were going to have the confidence to invest in gas.
The FTA is also called for incentives on congestion charging and tolls for gas vehicles, especially in areas of poor air quality.
Justin Laney, general manager – fleet at John Lewis Partnership (JLP), pointed out that diesel had served the transport industry well, being “affordable, stable, widely distributed and easily handled”. It is very energy dense, and a litre of diesel will carry one tonne of freight 100 miles. But he added: “Each heavy truck burns 40 tonnes of diesel per year, producing 100 tonnes of CO2. We will miss our CO2 reduction target without widespread use of a low carbon fuel.”
JLP has set itself a target of reducing carbon emissions per case delivered by 45% by 2020. “We have got halfway there by applying best practice,” said Laney. “We can only do the other half by using a low carbon fuel.”
The retailer started out using pure plant oil as an alternative to diesel but stopped the trial last year when duty on this fuel rose 20ppl, making it 30ppl dearer than diesel, and concerns arose over the food v. fuel controversy surrounding biofuels.
Downsides
While biomethane is up to one third the carbon intensity of diesel, there are potential downsides. Methane’s greenhouse gas effect is 25 times worse than carbon dioxide, so it is essential to prevent leakage from storage tanks and vehicles, especially when filling tanks.
“If you leak just 3% you are back to the start on CO2 emissions,” said Laney.
He called on the environment and energy departments to recognise green gas certificates (GGCs) for transport carbon reporting. At present GGCs – which prove the green credentials of biogas – are only available to non-transport energy users when it comes to accounting for carbon emissions.
One operator that is committed to biomethane is Howard Tenens, which is switching 75% of its fleet to dual fuel by the end of 2013. Its group CRS director, Catherine Crouch, said biomethame was the “only option” to achieve its target of a 40% cut in carbon intensity.
It is using compressed rather than liquefied gas and has installed two refuelling stations, the second of which, at its Swindon depot, has been partly funded by the Technology Strategy Board.
Howard Tenens has achieved a range of 400 miles for its duel fuel trucks, and by using composite gas tanks and removing the AdBlue tanks has seen no weight penalty.
Slow development
Nick Blake, sales engineering manager for CVs at Mercedes-Benz, said the OEM was one of a number trying to further the cause of natural gas vehicles but it would “continue to be a challenge”.
However Mercedes-Benz believes that gas and especially biomethane is currently the best bet for a viable low carbon fuel. Blake said that biodiesel had fallen out of favour – “Euro-6 doesn’t like biodiesel” – and while hydrogen seemed attractive, fuel cells at £1m per truck “were a bit expensive”.
“Ten years ago I was told fuel cells were 10 years away – and that is still the same today,” he said.
Blake pointed out the slow pace and expense of developing new trucks. “Euro-6 took 11 years and €3.6bn to develop,” he said. “It had to be something new – to use the same technology would have meant an 8% fuel penalty and the customer would not have accepted that. In the end Euro-6 is 5% to 7% better on fuel.”
This development cost places a heavy burden on truck makers. “It takes a long time to respond to legislation,” said Blake. “At every new Euro standard, one truck maker has gone out of business.”
He concluded: “Without clear commitment from government it is too expensive develop technology that might not see the light of day. We need time and a clear market to develop specialist vehicles. Without support from government we will struggle to make the progress biomethane deserves. But I don’t like incentives – take them away and the purchase of vehicles stops.”
Echoing previous calls for a levelling of the playing field, Blake called on the government to adjust the Renewable Heat Incentive and the RTFO so there were the same levels of support for all users of biomethane. Government must also commit long term to a consistent policy on fiscal measures such as keeping fuel duty low on gas. “Manufacturers will not spend 11 years in development for a three year incentive,” he said. “If the UK had had a 10 year policy it would have transformed where we are today.”
The Technology Strategy Board Low Carbon Truck Demonstration Trial
The Technology Strategy Board (TSB) is running the government’s trial of low carbon CVs, funded with £11.3m of government money matched by the same investment from the project members.
The trial is not just looking at gas vehicles, said Jon Horsley, lead technologist, low carbon vehicles, at the TSB. “We don’t pick winners, we design good races,” he said.
Set up in 2012, the trial’s aims were to:
• Enable two-year fleet trials of ‘ready and relevant’ low carbon technology
• Produce lessons for fleets, providers and government
• Break the ‘chicken and egg’ mutual dependency and kickstart the installation of UK gas refuelling infrastructure
There are 13 collaborative projects funded under the trial involving a total of over 300 vehicles and 11 new public refuelling hubs.
“The key is to enable real fleets to put some hard mileage on these vehicles,” said Horsley. “In two or three years all the trial will be complete and will generate a public report.”
