Emissions mission
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A comprehensive report lists the most efficient ways to lower CVs emissions and how to encourage their use. CM highlights the most important points Words: David Wilcox Compressed natural gas (CNG) and dual-fuel engines are the most promising technologies for low-carbon trucks in the UK, according to a report commissioned by the Low Carbon Vehicle Partnership.
The report, Opportunities to overcome the barriers to uptake of low emission technologies for each commercial vehicle duty cycle, was commissioned on behalf of the Task Force on Fuel Efficient, Low Emission Technologies, a joint industry/government initiative promoting fuelefficient, low-emission road freight technologies. Sustainability consultancy company Ricardo-AEA compiled the report, which set out to identify and prioritise the technologies capable of reducing LGV carbon dioxide (CO2) emissions and suggest ways to encourage their use.
Key to Ricardo-AEA's study is the concept that no single technology is appropriate for all types of truck operation. The report identifies five duty cycles and ranks them in terms of their individual contribution to the UK's total truck CO2 emissions, based on typical fuel consumption, average annual distances and the number of vehicles in each duty sector. Long haul is by far the most significant of the five duty cycles, contributing 45% of the UK's total truck CO2 emissions, so even small improvements in the fuel efficiency (and hence CO2 emissions) of long-haul trucks have a significant effect on overall CO2 emissions. The least significant duty cycle is municipal, accounting for just 4% of total LGV CO2 emissions.
Ricardo-AEA carried out interviews and took online responses from fleet operators, truck manufacturers and technology suppliers to establish what are perceived to be the biggest barriers to the use of new fuels and lowcarbon technologies. As well as specific issues related to individual technologies, such as the limitations of the gas refuelling infrastructure, the 10 most-commonly cited general points included concerns about reliability, payback periods and loss of payload (see list below).
About 30 fuel, powertrain and vehicle technologies were evaluated, assessing their CO2 reduction potential for each of the five duty cycles. CO2 savings are quoted on a well-to-wheels (WTW) basis that includes the full effect of manufacturing and transport rather than simply measuring a reduction in tailpipe emissions. Stressing that there is no one-size-fits-all solution, the report singles out three key strategies that should be pursued: • switch to gas; • improve aerodynamic efficiency/reduce rolling resistance; • support uptake of hybrids and electric vehicles. With the weighting of the duty cycles factored in to produce a ranking of the top 21 opportunities for CO2 reduction, dual-fuel (diesel and CNG) long-haul trucks emerge with the best low-carbon credentials, with the potential to cut UK total truck CO2 emissions by 7%. That increases to 19% if the gas is biomethane (produced from digested waste) rather than mains gas. Next come dedicated natural gas long-haul trucks, provided they are running on CNG rather than liquefied natural gas (LNG); the report says WTW CO2 savings of LNG are believed to be inferior because LNG is shipped in bulk from the Middle East.
Battery-powered light urban delivery trucks are ranked third, with the potential to slice 5% off total LGV CO2 emissions. Their downside is a lengthy payback period of four to 10 years; exemption from inner city congestion charges is needed to achieve the lower end of this timescale. In contrast, applying aerodynamic improvements to long-haul trucks can reduce total LGV CO2 emissions by almost as much (3% to 4%) but with a payback period of no more than a year.
The report looked at predictive cruise control of the type recently introduced by Scania, Volvo and MercedesBenz. These systems can see the topography ahead by using GPS (paired with three-dimensional mapping or, in Volvo's case, an ability to recall the engine load from previous journeys) and modify the cruise control setting to suit the gradient. Predictive cruise control has a payback period of just one to two months on long-haul trucks, but it is capable of shaving just 1% off the total UK truck CO2 emissions and so is ranked no higher than 19th in the report.
Diesel-electric hybrids do not figure as prominently as many people might imagine, with hybrid urban delivery vehicles ranked ninth.
These can reduce total LGV CO2 emissions by up to 3%. Ricardo-AEA estimates that mechanical hybrid urban delivery vehicles could reduce the total by almost 2%. They capture and store the kinetic energy of a multistop delivery vehicle in a fast-spinning flywheel, releasing it back to the engine's crankshaft as the vehicle pulls away. Although the vehicle's fuel savings are likely to be only 15% — roughly half those of a diesel-electric hybrid — a flywheel hybrid is lighter and cheaper because it needs no battery pack.
Recommendations The report includes a host of recommendations and suggestions on how to overcome the hurdles that stand in the way of progress. "One of the most effective strategies," says the report, "is to encourage a largescale shift to the use of gas as a fuel to replace diesel." Fleshing out this principle, the report calls for the creation of a clear strategy on how to do this, including a guaranteed fuel duty differential that favours gas over diesel for a rolling 10 years, support for gas refuelling infrastructure and encouragement for more biomethane production.
Recommendations to improve truck aerodynamic and rolling resistance include the creation of an accreditation scheme to provide independent test data to supplement manufacturers' claims; reviewing vehicle dimensional legislation with a view to allowing add-on aero devices; permitting the use of wide-single drive tyres on 6x2 tractor units; and extending the recently introduced requirement to publish new tyre rolling resistance data to cover retread tyres.
The third of the report's main recommendations calls for support for the uptake of hybrids and electric vehicles. This includes extending the capital grant for plug-in electric vans to include trucks of up to 12-tonne GVVV and/or the creation of a Green Lorry Fund similar to the Green Bus Fund that already provides purchase grants for low-carbon buses.
Finally, the report urges the government to support the uptake of low-emission LGV technologies and fuels by offering a range of business incentives. These include enhanced capital allowances; differential charging for LGV road use according to CO2 emission reductions and air pollution; and granting a maximum weight limit derogation that would offset the weight penalty of low-carbon trucks, allowing them to carry the A Not so high same payload as conventional diesel equivalents. • hopes for hybrids: they ranked no higher than • Opportunities to overcome the barriers to uptake of ninth in the report's list of low emission technologies for each CV duty cycle can be the top 21 opportunities downloaded from the Low Carbon Vehicle Partnership TECHNOLOGY Duty cycle Technology/fuel Duty cycle CO2 saving IINTV/1 Total UK HGV CO2 saving IINTW1 Payback Long-haul Dual fuel 16% (CNG J/42% (biomethand 7% (CNG]/19% (biomethand 2-4 years Long-haul Natural gas vehicles 5-16% (CNG]/1%-5% (biomethand 2%-7% (CNGJ/27-29% (biomethand 1-3 years Urban delivery Electric vehicles 50% 5% 4-10 years Regional delivery Natural gas vehicles 16% (CNG]/42% (biomethand 1%-4% (C NGJ/15%-16% (biomethand 3-6 years Regional delivery Dual fuel 13% (CNG]/35% (biomethand 3% (CNG]/9% (biomethand 5-10 years Long-haul Aerodynamic improvements 3%-4% 3-12 months Construction Natural gas vehicles 5%-16% (CNGJ/61-65% (biomethand 1%-3% (CNG]/10% (biomethand 2-4 years Construction Dual fuel 13% (CNG J/35% (biomethand 2% (CNG]/j% (biomethand 3-5 years Urban delivery Hybrid vehicles (electric or flywheel) 15%-30% (15% for flywheel hybrids] 2-3% 5-8 years Urban delivery Natural gas vehicles 5%-16%(CNN/61%-65%(biomethand 1%-2% (CNG]/j%-7% (biomethand 4-7 years All Low rolling resistance tyres 1%-5% 1%-5% 2 months-18 years Construction Alternatively fuelled bodies 5%-10% 1 c/0-2c/ci 3-6 years Regional delivery Stop-start and idle shut-down 3% 1c/ci 1-2 years Urban delivery Stop-start and idle shut-down 6% 1c/ci 1-11/2 years Municipal Hybrid vehicles (electric or hydraulic) 15%-25% (15% for hydraulic hybrids] 1c/ci 4-16 years Municipal Natural gas vehicles 5%-16%(CNN/61%-65%(biomethand 0-1% (CNG]/2%-3% (biomethand 6-18 years Regional delivery Aerodynamic improvements 2%-5% 1c/ci 1-21/2 years Construction Aerodynamic improvements Up to 3% 1c/ci 5-10 months Long-haul Predictive cruise control 1%-2% 1c/ci 1-2 months Long-haul Reduced ancillary loads 1%-2% 1c/ci 1-3 months Municipal Alternatively fuelled bodies 10%-12% 0.5% 9 years+ INDUSTRY BARRIERS TO NEW TECHNOLOGIES AND FUELS • High up-front costs; • uncertainty about payback period; • lack of trust in manufacturers' claims and difficulty in measuring small savings; • cost and availability of gas refuelling infrastructure and limited choice of gas vehicles; • concern about reliability of new technologies; • loss of payload due to additional weight of alternative technology; • limited range and loss of flexibility; • belief that driver training and telematics give equivalent results with less cost and risk; • dimensional limits restrict use of aerodynamic aids; • difficulty in calculating greenhouse gas savings.