From the extraction of raw materials to its operational phase, battery electric trucks produced in Europe today can deliver the largest greenhouse gas (GHG) emission reductions over their lifetime, according to a new study by International Council on Clean Transportation (ICCT).
To reach the Paris Agreement goal, Europe needs to decarbonize its trucks and buses, the highest emitting vehicles on the road. They represent only 2% of vehicles on the road but contribute to a quarter of transport-related emissions. The European Commission’s Strategy for Sustainable and Smart Mobility aims to have 80,000 zero-emission trucks on the road by 2030.
The ICCT-study offers a comprehensive picture of the life-cycle emissions of different powertrains and fuel options of these vehicles on a harmonized basis.
Comparing GHG emissions
The ICCT European study compares life-cycle greenhouse gas (GHG) emissions of electric, hydrogen, natural gas, and diesel trucks and buses. Its results indicate a clear pathway to decarbonize the sector. Battery electric models can deliver the greatest emission reductions even when using the EU’s average electricity grid mix (which is not fully renewable yet but will continue to improve during the lifetime of the vehicles).
The methodology addresses not only CO2 emissions resulting from vehicle tailpipes but also the GHG emissions arising from the manufacturing of the vehicles and their components, vehicle maintenance, fuel production, and electricity production. The study factors in the changes in the average electricity and fuel mix during the lifetime of today’s vehicles.
“The problem is not the factory but the road. The high greenhouse gas intensity of driving a truck during its whole life offsets the GHG emissions generated during manufacturing or the production of the fuel or the energy it consumes. Our study addresses the uncertainties surrounding the share of emissions in all stages of the vehicle’s life. It shows that only battery electric and some fuel cell electric trucks can meet the climate targets in the sector,” says Nikita Pavlenko, ICCT’s Fuels Program Lead.
Comparing the different powertrains and fuel options reveals that battery electric trucks take the lead in reducing GHG emissions. When estimated over the whole lifetime of a battery-electric 40-tonne tractor-trailer entering service in 2021, these vehicles produce at least 63% lower emissions than diesel. As the grid continues to decarbonize, these emissions will fall. The study shows an 84% reduction in emissions when using only renewable electricity.
Hydrogen and biofuels?
Fuel cell electric trucks using hydrogen from fossil fuels produce 15% less GHG emissions than their diesel counterparts. The emissions reduction depends heavily on the source of hydrogen. With hydrogen produced with only renewable electricity, emissions fall by 85%. The GHG emission savings from hydrogen trucks are less than from a battery electric model using a non-renewable energy source.
Researchers have questioned the sustainability, and GHG emission savings associated with many commonly used biofuels, especially when effects such as emissions from indirect land-use change are considered. When the indirect land-use change emissions are included in a biofuel’s GHG emissions calculation, biofuel often does not provide any GHG savings compared to regular diesel.
“Increasing energy efficiency is the game-changing factor in shrinking the carbon footprint of battery electric trucks compared to the rest of the technologies. These models become the cleanest option even if the source of electricity is not fully clean. This is not the case for hydrogen trucks, which can become a promising option in the future if hydrogen is produced from a 100% renewable energy source. Today, their capacity to reduce emissions is still limited,” says Felipe Rodríguez, ICCT’s Program Lead.
In the scenarios, natural gas trucks and buses provide, at best, marginal GHG emission reductions compared to diesel. We find that 2021 vehicle models have life-cycle emissions ranging from 4% to 18% lower than their diesel counterparts. Methane, a potent GHG that leaks from the vehicle and throughout the production and supply of natural gas, is a significant driver of the powertrain’s emissions. However, the benefits from natural gas vehicles disappear when looking at short-term warming impacts, which result in 0% to 21% greater GHG emissions than diesel vehicles over natural gas trucks’ full lifecycle.
“The climate benefits of natural gas urban buses compared to diesel are marginal at best when compared to diesel. Methane leakage may undermine the benefits of transitioning bus fleets to natural gas. Cities should consider their transport policy strategies with these numbers at hand,” says Mr. Pavlenko.