Environmental impact assessment of combined biochar and bioenergy production

The study evaluates the environmental impact of the co-production of bioenergy and biochar through biomass gasification, aiming to replace natural gas heating and peat in the horticulture substrate market. The syngas can provide sustainable greenhouse heating and biochar is currently considered as a peat substitute offering carbon sequestration potential when disposed in the soil due to its higher carbon recalcitrance compared to peat. The carbon footprint of four feedstocks is followed, namely willow and pine from tree nurseries, grade A wood pellets from demolition wood and park residues, including the growth and the decay rates of organic matter, peat and biochar, and taking into account the CO₂ emissions timing. The feedstock source and physical properties play an important role in the environmental impact of the production of bioenergy (process heat) and biochar. Peat replacement by biochar reduces the current pressure on the environment caused by peat extraction and use. When biochar is stored permanently in the soil as a disposal option, the corresponding negative CO₂ flux further reduces the total CO₂ emissions acting as a carbon capture and storage tool.