Reductions in greenhouse gas emissions through innovative co-production of bio-oil in combined heat and power plants

Abstract

Integrating fast pyrolysis into existing biomass-based combined heat and power (CHP) plants offers an innovative opportunity for plant operators to acquire an additional heat sink and produce a renewable transport fuels feedstock. This technology is particularly interesting in Sweden, where biobased heat and power constitute an important part of the energy system. It is important to establish the GHG emissions reduction of the production, through e.g. substitution effects in the transport sector, to ensure coherence with climate ambitions. In this study, the GHG emission avoidance methodology in the newly introduced EU Innovation Fund (IF) was adapted to determine whether integrating bio-oil production into an existing wood-fuelled CHP plant through fast pyrolysis would lead to a significant reduction in GHG emissions compared to the status quo. The results showed a reduction in GHG emissions of up to 0.24 MtCO2-eq per year, due mainly to the replacement of fossil fuels in the transport sector. A potential production volume in existing Swedish CHP plants was estimated to be 6.8–8.1 Mt of bio-oil annually, leading to a GHG emission avoidance of 8.6–10.3 MtCO2-eq/y, requiring a wood fuel input of 181–185 PJ/y. Sensitivity analysis indicated a significant potential for the reduction using input parameters for heating, electricity and hydrogen production whether pre-defined in the IF methodology or determined from case-specific conditions. However, the detailed results indicate that case-specific conditions should be used to reflect the fact that different European countries are at different stages in the transition to a fossil-free energy system. In conclusion, according to IF-based calculations, commercialisation of combined heat, power and bio-oil technology could lead to significant GHG emission avoidance across multiple sectors.