Volvo Trucks environmental director Lars Mårtensson has a potential solution as the transportation industry struggles to find alternative fuel sources that provide the power needed to move freight. His choice: natural gas.
Based at Volvo’s headquarters in Sweden, Mårtensson suggests a fuel mixture of gas and diesel may offer the best chance to wean ourselves off oil, and reduce carbon dioxide emissions as well.
He went on to say that the future fuel of choice should be climate-neutral biogas and the use of natural gas should be seen as a bridge to fully expanded production of biogas. Biogas is a non-fossil fuel that is formed when organic waste such as food scraps, manure, byproducts of the food industry and agricultural waste are broken down in an oxygen-poor atmosphere and transformed into methane gas and carbon dioxide.
“The production of biogas is beginning to get under way in many countries. We are currently living in a transition period; we are shifting from decades of oil dependency to a society structured around renewable fuels,” he explains.
One solution that has been proposed is the use of natural gas, but like oil, natural gas is a finite product.
“Natural gas is one of several alternatives. And natural gas can be better than oil since it produces lower carbon dioxide emissions,” says Magnus Swahn, president of consultancy firm Conlogic, which works on the development of sustainable logistics solutions.
The advantage of natural gas is that it releases 30-50% less carbon dioxide than oil and 40% less nitrogen oxide. It also does not release sulphur, heavy metals or ash, Volvo says.
An even better solution, Volvo believes, is the use of methane-diesel. Methane-diesel is created when gas and diesel is combined. The main power comes from methane gas but a smaller quantity of diesel serves as a sort of “liquid spark plug” to ignite the gas. If liquefied gas is used instead of compressed gas, the result is a far longer operating range.
“This is a highly elegant solution,” Mårtensson says. “It delivers the diesel engine’s high-energy efficiency combined with the low emissions of methane gas. I really like that combination.”
A big advantage to a methane-diesel engine is the ability to use straight diesel fuel when necessary, Mårtensson says.
“A gas-powered truck harnessing the methane-diesel engine’s energy efficiency is a natural advantage since it can also be run solely on diesel,” says Lars Mårtensson. “This is both practical and reassuring since the gas filling station infrastructure has not yet been fully expanded.”
Volvo Trucks is now running field tests of methane-diesel engines running 70% gas and a 30% bio-blend diesel made from fossil-based diesel mixed with a green diesel made from renewable materials.
“The aim is that we should run on 80% green biogas and 20% green biodiesel as the combustion agent. This will make carbon dioxide emissions 80% lower than with conventional diesel power,” says Mårtensson.
The tests are ongoing in Europe.