It’s clear that the transportation industry needs to reduce its carbon footprint and move away from fossil fuels. But two big questions remain: what is the best alternative for heavy-duty trucks, and what sustainable options are already available today?
Currently, multiple technologies are being proposed as the answer, including battery electric and hydrogen fuel cells, as well as renewable fuels such as hydrogenated vegetable oil (HVO) and bio-LNG. Each has its own advantages and limitations when it comes to development, infrastructure, cost and life cycle environmental impact.
Maria Grahn, Associate Professor at Chalmers University of Technology, works extensively within the areas of energy systems analysis and researching future fuels for transportation. “Our aim is to better understand the different options, in the hope that we can help guide governments and policymakers to find the best alternative for them,” she explains. “There are a lot of different scenarios and questions that remain to be answered. But under current circumstances, we see clear trends and tendencies towards certain fuel types.”
As part of her work, Maria has contributed to modelling future fuels and trends to help predict which fuels are most likely to be used for various modes of transport, including shipping, aviation, and passenger cars. When it comes to heavy-duty vehicles, the industry is moving in a clear direction.
“In Europe at least, if regulations effectively prohibit almost all tailpipe CO2 emissions, then in practice there are only two options: battery-electric and hydrogen. When we model the future fuel mix for heavy-duty trucks, we can see that these two fuels are likely to dominate going forward.”
The short answer is both – but which of the two is best for any given situation is likely to come down to multiple factors such as the weight and size of the vehicle, the distance travelled, the availability of fuel and accessibility to refuelling infrastructure.
“The main challenge is the infrastructure, particularly when it comes to hydrogen because it is difficult to move,” says Maria. “There is also the question of where all the electricity will come from. Not just to power electric vehicles, but for producing the amount of hydrogen that will be needed. Apart from transportation, other industries such as steel and chemical production will likely need a lot of hydrogen going forward too. As a society, we will need to generate a lot of cheap electricity to meet this demand, and it has to come from renewable sources.”
In general, with today's technologies the shorter the distance, the easier it will be to use battery-electric trucks since they have limited ranges and require places and times to recharge. For longer distances, where access to charging infrastructure is limited, hydrogen fuel cells will likely be a future option since ranges are longer and refuelling times much shorter. But hydrogen trucks still belong to the future. Battery electric trucks are already available and could decarbonize a big share of European goods transports today.
Given that battery-electric heavy-duty vehicles are relatively new on the market and hydrogen fuel cells are still in development, conventional internal combustion engines are expected to remain for some time yet. In fact, there could still be a place for combustion engines in a post-fossil fuel world, using alternative fuels and then not only biogas but also hydrogen and electrofuels.
“Electrofuels are produced by combining hydrogen with carbon, to create almost any type of fuel you want,” explains Maria. “The main advantage is that many electrofuels can be used in the same engines and refuelling infrastructure as conventional fuels. Our modelling shows that such fuels will likely be used in the shipping and aviation industries. And for some of the more demanding road assignments that cannot be met with battery-electric or fuel cell technology, electrofuels or hydrogen could be the answer.”
For any operator whose daily operations are within 300 kilometres, an electric truck is already a viable fossil-fuel free option
While it can seem like most potential fossil fuel-free solutions evolve around technologies that are still in the pipeline, biogas driven long haul trucks and battery-electric trucks for distribution and regional transport are already on the market today.
“For any operator whose daily operations are within 300 kilometres, an electric truck is already a viable fossil-fuel free option,” says Lars Mårtensson, Director Environment & Innovation, Volvo Trucks. “This is based on one overnight charge, and if integrating top-up charging in the truck’s schedule is possible – which will be easier as the public charging infrastructure continues to expand – then its range will be even longer.”
The current status when it comes to renewable fuels – whether you’re talking about biodiesel, HVO or bio-LNG – differs from market to market. For example, consumption of biodiesel is increasing in France. Companies like Shell are ramping up production of bio-LNG filling and making it more accessible to truck drivers, while all over Europe the refuelling network is rapidly growing. Finnish HVO producer Neste is currently expanding its plant in Singapore, making it the world’s largest. However, in each case the availability of raw materials for production is expected to be a limiting factor.
When it comes to hydrogen fuel cells, Volvo Trucks completed its first tests in 2022, and will commence customer field tests in some years. The ambition is to launch a commercial offer in the second half of the decade.
“We’re seeing multiple solutions being developed concurrently because many people in the transportation industry can see that there is no silver bullet that will solve the climate challenge,” says Lars. “But it’s important to remember that these technologies will complement each other, not compete. So, if you’re looking to transition away from fossil fuels, don’t wait and see which technology ‘wins’ – you can start looking now at developments and available options in your local market. The solution you’re looking for to cut carbon emissions is probably already available.”
To hear more from Maria Grahn, watch a short film where she shares her views on a fossil fuel-free transportation industry.