Biomethane produced from maize grown on peat emits more CO2 than natural gas

Abstract

Cultivation of maize for biomethane production has expanded rapidly, including on drained peat soils. The resulting soil CO2 emissions at the point of feedstock production are largely overlooked when assessing biogas climate mitigation potential. On the basis of field-scale flux measurements, we calculate that soil CO2 emissions from biomethane feedstock production on drained peat exceed embodied emissions for an equivalent amount of natural gas by up to a factor of three. Biogas is promoted as an alternative fuel with the potential to lower net CO2 emissions. However, here the authors calculate that growing biogas feedstock crops on drained peatlands may produce three times more CO2 than burning natural gas.