Life cycle assessment of waste-to-hydrogen systems for fuel cell electric buses in Glasgow, Scotland

Waste-to-hydrogen (WtH) technologies are proposed as a dual-purpose method for simultaneous non-fossil-fuel based hydrogen production and sustainable waste management. This work applied the life cycle assessment approach to evaluate the carbon saving potential of two main WtH technologies (gasification and fermentation) in comparison to the conventional hydrogen production method of steam methane reforming (SMR) powering fuel cell electric buses in Glasgow. It was shown that WtH technologies could reduce CO₂-eq emissions per kg H₂ by 50-69% as compared to SMR. Gasification treating municipal solid waste and waste wood had global warming potentials of 4.99 and 4.11 kg CO₂-eq/kg H₂ respectively, which were lower than dark fermentation treating wet waste at 6.6 kg CO₂-eq/kg H₂ and combined dark and photo fermentation at 6.4 kg CO₂-eq/kg H₂. The distance emissions of WtH-based fuel cell electric bus scenarios were 0.33-0.44 kg CO₂-eq/km as compared to 0.89 kg CO₂-eq/km for the SMR-based scenario.