Volvo is planning to use methane gas to power diesel engines in its trucks in the future.
Volvo says that a diesel engine has a 30 to 40 per cent better efficiency rating than an ordinary spark plug engine running on petrol or an internal combustion engine. Whatever fuels either engine type runs on, the diesel engine is always far more energy-efficient, which is why all heavy vehicles have diesel engines.
With compressed methane gas in the tanks, a gas-powered truck with an internal combustion engine can drive 150-200 kms without refuelling. With the same amount of gas in a truck with a methane diesel engine, the range is twice as long.
Volvo Trucks’ aim is for its trucks to operate on 75% methane gas and 25% diesel in the initial stage. Optimum efficiency is achieved if the methane gas is chilled to -160ยบC as, at that temperature, the gas becomes liquid, the volume is reduced and you get twice the amount of fuel. With liquid methane gas in the tank and a fuel consumption of 75% methane gas and 25% diesel, it is now possible to drive more than 500 kms before refuelling.
This means that for transport companies performing long daily transport jobs and returning to the same filling station, Volvo’s methane diesel technology is already a viable option.
At present, the network of filling stations that distribute liquid methane gas is unevenly developed in Europe. There are plenty of filling stations in the UK, while some countries, such as Sweden, have none at all. However, filling stations will soon be built in Sweden’s three largest cities.
Gas trucks with a methane diesel engine can run on only diesel, which is practical and safe when filling stations are few and far between.
A common argument against methane gas is that natural gas has to be used because not enough biogas is produced. Critics argue that replacing one fossil fuel with another is unsatisfactory.
Volvo believes that using natural gas is one way of getting through this transition period until biogas production has been fully developed. Running engines on both biodiesel and biogas could reduce carbon emissions by almost 80% compared to traditional diesel operation.
Field testing of methane diesel engines will start in the UK and Sweden during 2010. The public sector, with its sustainability targets, is a key target for Volvo.
Keywords: Volvo trucks methane diesel engines