Natural gas has been going through something of a resurgence of late as long-distance operators search for fuel types that can offer lower CO2 emissions, high mileages between fill-ups, and lower costs.
For instance, supermarket Sainsbury's currently has five dual-fuel (diesel and biogas) Mercedes-Benz units on trial – supplied by Clean Air Power (CAP) – and, as Motor Transport
reported earlier in the year, CAP has been trialling its dual-fuel units on Volvo engines as a potential line-fit option, as well as a retrofit alternative using its Genesis product (MT 15 January).
That retrofit technology is now up and running and MT has put it through its paces. The product in question was a CAP liquefied natural gas (LNG) conversion fitted to a Euro-5 Volvo FM13 6x2 tractor.
The results were certainly encouraging: it used 21.5 litres of diesel, combined with 9.8kg of LNG at 39% diesel substitution.
With diesel priced at 0.88p*/litre and LNG at 0.95p*/kg, the overall cost is £28.23. If the engine had been powered solely by diesel, the cost would have been £31.06, thus the dual-fuel operation gives a cost saving of 9%, or £2.83 over 100km. Multiply that against an annual mileage of 100,000km and it delivers an annual saving of
£2,830.
Key areas for high gas use are motorways, dual-carriageways and steady inclines where the engine's peak torque operates – in those situations as much as 80% LNG can replace diesel.
Using LNG reduces the vehicle's carbon footprint by 10%. According to calculations from the Department for Environment, Food and Rural Affairs, the truck produces 91,178kg of CO2 using diesel and 43,063kg CO2 from LNG over 100,000km in 12 months.
Using only diesel, CO2 emissions would have been 149,472kg: 15,231kg more than the combined diesel and LNG operation.
CAP says increased savings can be made with higher mileage on suitable roads and by the bulk purchase of fuel. The conversion is also available for compressed natural gas (CNG).
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