Life cycle assessment of a fuel cell electric agricultural tractor with decentralised biogenic hydrogen supply

Abstract

Agricultural tractors remain predominantly fossil-diesel-powered, yet the transition to zero-emission operation is technically challenging, and no life-cycle evidence exists to date for medium-power fuel cell electric tractors or their integration with decentralised biogenic hydrogen supply. This study presents the first cradle-to-grave life cycle assessment (LCA) of FCTRAC, a 95 kW fuel cell electric tractor prototype, combined with the BioH2Modul-prototype, a decentralised biomass gasification system producing high-purity hydrogen. Global Warming Potential (GWP) and Cumulative Energy Demand (CED) are assessed in accordance with ISO 14040/ISO 14044, using 1 kWh of mechanical energy at tractor service level as the functional unit. FCTRAC yields a life-cycle GWP of 349 gCO₂/kWh and a CED of 9.90 kWh/kWh, with 90 % from renewable sources. The hydrogen supply chain dominates life-cycle GWP (84 %), driven by electricity demand for BioH2Modul auxiliaries (38 %) and hydrogen refuelling station compression (20 %). Under an energy scenario with renewable wood chips logistics and renewable electricity, the BioH2Modul delivers hydrogen at 21 gCO₂/kWhH₂, reducing total life-cycle GWP to 125 gCO₂/kWh – a 90 % reduction relative to conventional diesel operation. Vehicle production of FCTRAC (18.2 tCO₂) exceeds that of the diesel reference (10.5 tCO₂), with carbon-fibre hydrogen storage vessels as a hotspot. Life-cycle GWP and CED are primarily governed by the hydrogen production pathway rather than vehicle lifetime or load profile. Under renewable conditions, the BioH2Modul achieves GWP values competitive with renewable-electricity-based electrolysis, indicating that decentralised biogenic hydrogen can potentially become a GWP-competitive pathway for zero-emission agricultural mechanization.