Assessment of biomass uses in Helsinki for biochar and bioenergy production for climate change mitigation

Abstract

Woody biomass is an essential resource for renewable energy production in Finland. It is considered an alternative to fossil fuels in the energy sector. However, that comes with certain provisions in terms of sustainability that have been extensively researched over the years – concerns over land use and land use changes, as well as forest carbon stocks. When sourced sustainably, it represents a flexible resource, with the ability to service large end-users (district heating, transportation, energy production, etc.). Woody biomass also represents a viable opportunity for uses in climate change mitigation projects, such as biochar production and applications. Historically, biochar has been used as a soil amendment for improved agricultural output. However, it also represents a viable solution for climate change mitigation due to its carbon sequestration potential.

This master’s thesis aims to explore the climate change effects and greenhouse gas emissions of biomass uses in Helsinki, with a focus on biochar and bioenergy production. To achieve this, a comparative prospective cradle-to-gate life cycle assessment (LCA) has been performed. The two scenarios have been biochar and syngas production and bioenergy from biomass produced in a combined heat and power (CHP) plant. The impact category Global warming potential (GWP) has been investigated to achieve to goals of the study. The results show significant carbon sequestration possibilities for biochar, with additional benefits of heat from syngas delivered to the district heating system of the city.