Toward lower-emission freight: Grid infrastructure tradeoffs of battery-electric vs fuel cell trucks in New Zealand

Trucking is critical for New Zealand's economy as it is responsible for most of the country's freight movement. However, the reliance on diesel-powered trucks disproportionately contributes to carbon dioxide (CO2) and air pollutant emissions. Two different technologies have the potential to electrify heavy freight: battery-electric and fuel cell electric trucks; however, it remains unclear which technology will be used to reach New Zealand's goal of net-zero freight transportation emissions by 2050. In this study, we develop an integrated assessment framework that quantifies present-day heavy truck emissions in New Zealand and compares the energy requirement of decarbonization through battery-electric versus fuel cell trucks in 2035 and 2050. This framework includes freight demand, vehicle powertrain, truck operation and charging, and diesel emission models. Further, we quantify the electricity grid infrastructure requirements of the shift to battery-electric and fuel cell truck fleets using the REMix-NZ capacity expansion model. Results show that the current fleet of heavy diesel trucks in New Zealand emits 2.4 million tonnes of CO2 eq. annually, which could be fully mitigated by 2050 through battery-electric or fuel cell fleets. A full fleet of battery-electric trucks in 2050 would consume 7.2 % of New Zealand's current electricity generation compared to 13.5 % for fuel cell trucks. A sensitivity analysis shows that improved truck design and efficiency can reduce this electricity requirement. Up to 3.6 GW additional capacity would need to be built by 2050, primarily through solar power, to satisfy the energy demand of a battery-electric truck fleet compared to 5.3 GW for a fuel cell fleet.