Flexibility and resilience in the transition to a carbon-neutral Finnish energy system

As climate change caused by anthropogenic carbon emissions continues to present a major threat to humanity, the energy sector has a central role in combatting carbon emissions. Inspired by the 2015 Paris Agreement, the European Union has a binding goal of attaining carbon neutrality by 2050. Finland has its own legally binding goal of attaining carbon neutrality already by 2035. In this thesis, the transition towards a carbon neutral energy system in Finland is investigated. This thesis is based on both power and energy system simulations on an hourly resolution. While the power sector in Finland is already mostly decarbonized, heating, industry and transport sectors still require extensive decarbonization measures. This thesis investigates the transition from three different aspects. First, this thesis investigates the technical feasibility of a carbon-free power system. Second, decarbonization methods in industry and transport are investigated. Third, aspects such as economic dispatch, security of supply and demand response are evaluated. This thesis finds that introducing either energy storages, flexible power generation or demand is essential to facilitate the transformation to a carbon neutral energy system. This is due to increasing share of variable renewable electricity generation. Introducing electrification to other sectors such as heating, or industry increases the need for flexibility. Two clear flexibility roles are found: short-term flexibility to counter wind variability and long-term flexibility for seasonal demand variation. Both of these are needed for increasing resilience in the energy system in the transition towards carbon neutrality. Flexibility can be provided either by generation or by varying load. Demand-side management affects especially the short-term flexibility needs. Additionally, to attain carbon neutrality, decarbonization measures must be taken across the energy sector. When industry and transport sectors are decarbonized with electrification, both directly and indirectly via green hydrogen as energy carrier, carbon emissions decrease significantly, and carbon neutrality is possible. However, carbon sinks also need to be considered, therefore increasing biomass usage for electricity and heat production is not a suitable option. Future research should include the whole Nordic electricity system, integrated with heat and hydrogen sectors. This would enable a more comprehensive analysis and help in more accurately quantifying the amount of needed flexibility.