Coca-Cola Enterprises releases biomethane vehicle trial report; buys 14 gas trucks to run on biomethane based on results
|Well-to-wheel emissions for gas and diesel trucks over the CCE drive cycle. Source: Cenex report. Click to enlarge.|
Coca-Cola Enterprises (CCE) in the UK has released a report on the trial of a heavy-duty truck operating solely on biomethane gas.
The report showed the gas vehicle provided similar drive performance and reliability levels to incumbent diesel technologies in fleets. When operating on biomethane, well-to-wheel emissions of CO2 were significantly reduced. Gas vehicle operation also reduced emissions of NOx, PM and noise. The report also found that challenges in terms of ownership cost still need to be overcome. On conclusion of the trial, CCE invested in a fleet of 14 gas Iveco Stralis vehicles and a gas station which is due to be operational at its Enfield depot in June 2012.
The new CCE gas fleet will consume approximately 168 tonnes of biomethane saving more than 300 tonnes of CO2, 1,590 kg of NOx and 33 kg of PM emissions per year.
CCE contracted Cenex to evaluate and compare the emissions, fuel consumption, economics, reliability and operability of a 26-tonne Iveco Stralis gas vehicle with that of a diesel Stralis vehicle. The trial vehicles—one operating solely on biomethane gas, and one diesel-powered—were highly comparable. Both were new registrations at trial commencement and met Enhanced Environmentally friendly Vehicle emission standards (emission levels between the current Euro V standard and the future (2013) Euro VI levels).
The gas vehicle had a small payload penalty of 700 kg due to the additional weight of the fuel tanks. The gas vehicle was supplied with a fully automatic gearbox whereas the diesel vehicle incorporated an automated manual transmission.
|Iveco Stralis CNG (biomethane)||Iveco Stralis Diesel|
|GVW||26 tonnes||26 tonnes|
|Max. payload||18.2 tonnes||18.9 tonnes|
|Engine capacity||7.79 L||7.79 L|
|Engine power||272 PS||310 PS|
|Emissions aftertreatment||3-way catalyst system||SCR catalyst system|
|Gearbox||6-speed automatic||12-speed automated manual|
|Fuel tank capacity||880 liters @ 200 bar||300 liters|
Biomethane is the term given to biogas that has been upgraded (i.e. unwanted gases and contaminants have been removed) to vehicle fuel quality which typically has a high > 95% methane (CH4) content. Biogas is created from the anaerobic digestion of organic matter and contains approximately 60% CH4 and 40% carbon dioxide (CO2), plus very small quantities of oxygen (O2), carbon monoxide (CO), and nitrogen (N2).
The amount of CO2 produced by combusting biomethane is similar to the amount of CO2 absorbed by the organic matter during its growth. The release of this CO2 is part of a sustainable carbon cycle—hence, biomethane is a renewable fuel. The UK is one of the largest producers of biogas from landfill sites in Europe.
A temporary gas vehicle refueling infrastructure was installed at the CCE depot in Enfield, UK from which the trial vehicles were operated. Vehicle activity data from the Enfield depot was logged via onboard telemetry. The CCE drive cycle was a 30-minute, 19.5 km cycle statistically representative of vehicle distribution patterns from Enfield. Testing vehicles over the CCE drive cycle in an emissions testing facility allowed air quality performance as well as tailpipe CO2 and fuel consumption to be measured in a controlled and repeatable environment.
Among the findings of the study were:
Biomethane gas vehicle operation reduced NOx and PM emissions by 85.6% and 97.1% respectively.
The gas vehicle achieved a 50.3% saving in well-to-wheel GHG emissions, compared to the diesel Stralis vehicle. However, this was achieved using a temporary filling station—a more efficient permanent station being installed at the CCE depot raises the GHG saving to 60.7%.
The gas truck consumed 34.9 kg/100 km compared to the diesel truck that consumed 31.9 liters/100 km (7.4 mpg US) over the CCE drive cycle. This equated to a theoretical vehicle range of 357 km and 940 km (222 and 584 miles) for the gas and diesel trucks respectively.
The overall reduction in efficiency from the diesel to gas vehicle over the CCE drive cycle was 31.8%.
The gas vehicle achieved an availability rate of 99.2% during the 12 month vehicle trail compared to an availability rate of 100% for the diesel vehicle.
Gas vehicle operation reduced noise levels by 4.1 dB(A), 10.5 dB(A), and 8.1 dB(A) during low speed drive-by, engine idle and hot engine start conditions respectively.
Drivers rated the overall performance of the gas vehicle higher than the diesel. Drivers were most impressed with the gas trucks acceleration, transmission and refueling aspects.
Operating the gas vehicle on biomethane reduced the fuel costs by 12.8%. However, the total cost of ownership increased by 15.3% primarily due to the additional capital cost of the gas vehicle. Estimated future cost reductions between the vehicle technologies coupled with a further reduction in gas price due to either a higher volume supply or the use of a public gas refueling station would achieve a similar total cost of ownership between the two vehicle technologies.