Carbon-negative hydrogen: Exploring the techno-economic potential of biomass co-gasification with CO₂ capture

The hydrogen economy is receiving increasing attention as a complement to electrification in the global energy transition. Clean hydrogen production is often viewed as a competition between natural gas reforming with CO₂ capture and electrolysis using renewable electricity. However, solid fuel gasification with CO₂ capture presents another viable alternative, especially when considering the potential of biomass to achieve negative CO₂ emissions. This study investigates the techno-economic potential of hydrogen production from large-scale coal/biomass co-gasification plants with CO₂ capture. With a CO₂ price of 50 €/ton, the benchmark plant using commercially available technologies achieved an attractive hydrogen production cost of 1.78 €/kg, with higher CO₂ prices leading to considerable cost reductions. Advanced configurations employing hot gas clean-up, membrane-assisted water-gas shift, and more efficient gasification with slurry vaporization and a chemical quench reduced the hydrogen production cost to 1.50–1.62 €/kg with up to 100% CO₂ capture. Without contingencies added to the pre-commercial technologies, the lowest cost reduces to 1.43 €/kg. It was also possible to recover waste heat in the form of hot water at 120 °C for district heating, potentially unlocking further cost reductions to 1.24 €/kg. In conclusion, gasification of locally available solid fuels should be seriously considered next to natural gas and electrolysis for supplying the emerging hydrogen economy.