Life cycle energy consumption and GHG emissions of hydrogen production from underground coal gasification in comparison with surface coal gasification

Developing underground coal gasification (UCG)-based hydrogen production (UCG-H2) is expected to alleviate hydrogen supply and demand contradiction, but its energy consumption and environmental impact need to be clarified. In this paper, comparative study of energy consumption and greenhouse gas (GHG) emissions between UCG-H2 and typical surface coal gasification (SCG)-based hydrogen production (SCG-H2) is carried out using life cycle assessment method. Result shows energy consumption of UCG-H2 is only 61.2% of that of SCG-H2, which is 1,327,261 and 2,170,263 MJ respectively, reflecting its obvious energy saving advantage. 80% capture rate can achieve an appropriate balance between energy consumption and emissions. Under this capture rate, emissions of UCG-H2 and SCG-H2 are roughly equivalent, which are 207,582 and 197,419 kg CO2-eq respectively. Scenario analysis indicates energy consumption in hydrogen industry can reduce by 38.8% when hydrogen production is substituted by UCG with CCS to fully meet demand of 21 Mt in 2030.