A comprehensive review on environmental and economic impacts of hydrogen production from traditional and cleaner resources

This review evaluated hydrogen (H2) production methods from fossil fuels, biomass, and water, assessing their economic, environmental, and energy impacts. Biomass-based methods, such as photo-fermentation (PF), dark fermentation (DF), and microbial electrolysis cell (MEC), were found to be more environmentally friendly, with PF showing the lowest global warming potential (1.88 kgCO2 eq./kgH2) and acidification potential (0.003 gSO2/kgH2). In contrast, fossil fuel-based gasification exhibited the highest environmental impact, with 19.85 kgCO2 eq./kgH2 and 0.139 kgSO2/kgH2 due to coal mining and transport.

Although hydrogen production consumes water (e.g., 9 kg of water per 1 kg of H2 via electrolysis), the hydrogen ecosystem significantly reduces the water footprint as H2 converts back to water in fuel cells. Fossil fuel-based methods, like gasification and steam-methane reforming, remain more cost-efficient at scale, though rising carbon costs may enhance the competitiveness of biomass-based H2. Biomass-based processes are promising for sustainable and moderately cost-effective H2 production.