Production of purified H2, heat and biochar from wood: Techno-economic and life cycle assessment of small scale units

Abstract

Hydrogen is forecasted to contribute to the energy transition. This study evaluates the production of purified H2, heat and biochar from woodchips. Three pyrogasification processes are compared: gasification (O2/H2O) with or without catalytic reforming and water gas-shift, autothermal pyrolysis. Techno-economic and life cycle assessments were conducted based on detailed mass and energy balances. On the economic front, the historical market prices of hydrogen, heat and biochar are not sufficient to reach profitability. The subsidies required to reach profitability and the avoided CO2 emissions from reference steam methane reforming (SMR) process were evaluated. It is estimated between 130 and 310€/tCO2 avoided which can be reduced with higher price of hydrogen. On the environmental front, the pyrogasification processes are more attractive than SMR regarding global warming, ozone depletion layer and fossil fuel consumption potentials. Meanwhile, the acidification potential and the photochemical oxidant formation are higher than SMR.