Supporting material: Prospective life-cycle assessment of sustainable alternatives for road freight transport

This study investigates decarbonization pathways for the road freight transport sector by evaluating three alternatives to conventional diesel trucks: trucks powered by biofuels, battery electric trucks, and fuel cell trucks with hydrogen. A prospective life cycle assessment of these options is conducted under two policy scenarios for decarbonization across 12 distinct regions over the century. Employing a cradle-to-grave approach, the assessment covers activities from fuel and electricity production to the end-of-life of truck components. Findings reveal that, in eight of the 12 regions examined, an early transition to battery electric trucks could increase life-cycle greenhouse gas emissions by up to 70% by 2030 compared to the continued use of conventional diesel trucks, underscoring the significance of liquid fuels for short to medium-term decarbonization. However, in the long term, as electricity mixes and hydrogen production are decarbonized, battery electric trucks and hydrogen fuel cell trucks emerge as superior alternatives in all regions, emitting, at least, 29% less greenhouse gases than trucks powered by biofuels, and 45% less than diesel trucks. The optimal transition from conventional diesel trucks to trucks powered by biofuels and, subsequently, to battery electric trucks and/or hydrogen could avoid 134-204 Gt CO2-eq worldwide and prevent a temperature rise of 0.22-0.33°C compared to the diesel-based scenario. This emphasizes the crucial role of appropriate policies for the timely transformation of the road freight transport sector.本研究针对公路货运行业的脱碳路径展开探究，评估了传统柴油卡车的三类替代方案：生物燃料动力卡车、电池电动卡车（battery electric trucks）以及氢燃料电池卡车（fuel cell trucks with hydrogen）。本研究采用从摇篮到坟墓（cradle-to-grave）的全流程研究范式，针对12个不同区域，在两种脱碳政策场景下，对上述方案开展了覆盖百年周期的前瞻性生命周期评估（Life Cycle Assessment, LCA），评估范围涵盖从燃料与电力生产，直至卡车组件报废回收的全链条活动。研究结果显示，在12个受评估区域中的8个，若在2030年前过早转向电池电动卡车，其全生命周期温室气体排放量相较持续使用传统柴油卡车最高将增加70%，这凸显了液态燃料在中短期脱碳进程中的重要意义。不过从长期视角来看，随着电力结构与氢能生产实现脱碳，电池电动卡车与氢燃料电池卡车将成为所有区域的最优替代方案，其温室气体排放量至少较生物燃料动力卡车低29%，较柴油卡车低45%。若按照最优转型路径——从传统柴油卡车先过渡至生物燃料动力卡车，再进一步转向电池电动卡车和/或氢燃料电池卡车，全球范围内可累计减少134至204亿吨二氧化碳当量（CO₂-eq）的排放，相较以柴油为动力的基准场景，可避免0.22至0.33摄氏度的温升。这充分彰显了适配政策对公路货运行业及时转型的关键作用。