Assessing Heavy Duty Vehicle CO2 Emissions for Qualification as a Zero Emissions Vehicle

The global transportation industry, and road freight in particular, faces formidable challenges in reducing Greenhouse Gas (GHG) emissions; both Europe and the US have already enabled legislation with CO2 / GHG reduction targets. In Europe, targets are set on a fleet level basis: a CO2 baseline has already been established using Heavy Duty Vehicle (HDV) data collected and analyzed by the European Environment Agency (EEA) in 2019/2020. This baseline data has been published as the reference for the required CO2 reductions. More recently, the EU has proposed a Zero Emissions Vehicle definition of 3g CO2/t-km. The Zero Emissions Vehicle (ZEV) designation is expected to be key to a number of market instruments that improve the economics and practicality of hydrogen trucks. This paper assesses the permissible amount of carbon-based fuel in hydrogen fueled vehicles – the Pilot Energy Ratio (PER) – for each regulated subgroup of HDVs in the baseline data set. The analysis indicates that a PER of ~4% is required to address the key long-haul groups (5LH, 9LH and 10LH) and potentially some Regional Distribution vehicles, but that much lower PERs are required for most of the Regional and Urban Delivery vehicles in this group. The assessment then looks at the impact of the actual vehicle configuration and identifies features impacting the PER such as rear axle ratio; for example, an engine may be capable of meeting the Zero Emissions requirement, but rear axle ratios greater than 3 may still cause a specific vehicle configuration to exceed 3g/t-km of CO2. The paper concludes by assessing the existing technology options to meet the ZEV requirements and the current state of these technologies against the required PER target.