Route-based time-dependent life cycle greenhouse gas and NOₓ emissions analysis of heavy-duty trucks

The electrification of Class-8 heavy-duty (HD) trucks is gaining traction due to the potential for greenhouse gas (GHG) emissions reductions to combat climate change. Hence, a life-cycle analysis (LCA) must be used to conduct a comprehensive emissions analysis of the vehicle's lifecycle. The current literature lacks studies conducted on Class-8 trucks, time-of-day impact on GHG emissions from electricity generation, and nitrogen oxide (NOx) emissions. Therefore, the goal of this paper is to investigate the potential GHG and NOx emissions reductions achieved with battery electric (BE) and series-hybrid (SHE) trucks when compared to a conventional diesel internal combustion engine (ICE) Class-8 truck using a regional and time-of-day dependent electricity grid. A vehicle simulation tool was used to connect modular powertrain components to simulate the real-time performance, energy consumption, and emissions of the three powertrains with dynamic drive cycle data as input. Additionally, the LCA accounted for emissions uncertainties from manufacturing, maintenance, fuel, and electricity production using a Monte Carlo simulation. The truck's emissions were evaluated over a cross-country highway “long-haul” route and two urban “drayage” routes for last-mile delivery. A future grid assumption was applied to the time-dependent grid to take the increase in the use of renewables over ten years into account. The LCA results show that for drayage routes in regions with a large share of renewable sources of electricity, BE trucks are best suited for operation, emitting 22 % less GHG and comparable NOₓ to the SHE truck. On the other hand, along the long-haul and the drayage route in regions with significant use of non-renewable sources of energy, the SHE truck had the lowest emissions overall with 40 % and 48 % less GHG and NOₓ respectively than the BE truck. After considering future grid emissions reduction from 2023 to 2032, the BE truck's emissions were reduced by 10–13 % compared to the ICE truck. Despite this reduction, the BE truck had greater GHG and NOₓ emissions during long-haul and drayage operation in regions with emissions intensive grids than the SHE truck.