Negative emission strategies to reduce the carbon intensity of Brazilian sugarcane ethanol under RenovaBio

Abstract

Brazil’s National Biofuel Policy (RenovaBio) promotes negative emission technologies (NETs) as one of the instruments to reduce the carbon intensity (CI) of biofuels; however, no mill in the country has integrated such strategies into its production processes to date.

The present study examined the potential impact of two promising NETs (i.e, bioenergy with carbon capture and storage (BECCS) and field application of biochar) on the CI of sugarcane ethanol, calculated using the methodological approach adopted by RenovaBio. In addition, the assessment used data from the agricultural and industrial stages provided by 62 certified sugarcane mills.

Results show that these strategies have the potential to significantly reduce the CI of ethanol. The obtained value of +32.8 g CO₂e/MJ of hydrated ethanol (without NETs considered) could be reduced to +15.9 (with the application of 1.0 t biochar/ha), +10.4 (with BECCS from fermentation), and −81.3 (with BECCS from combustion). Ethanol-blended gasoline (produced in association with NETs) has the potential to reduce impacts; however, achieving reductions similar to those of electric and all-ethanol vehicles, when compared to conventional gasoline, would depend on NETs that are unlikely to be implemented (e.g. BECCS from combustion). Estimates show that the carbon credits made available in RenovaBio will probably not be sufficient to provide attractive financial viability. Other instruments, such as private funding through the voluntary carbon market (VCM) and specific national incentive policies, may be essential for financing NETs.