Early cross-sector decarbonisation for Europe’s hard-to-abate sectors: Insights from Denmark’s 2030 target

With a 70 % reduction target by 2030, Denmark is among the first countries to require deep decarbonisation in hard-to-abate sectors, such as transport and agriculture, after more accessible options are exhausted. Collectively with other ambitious countries, this might set a precedent for Europe. Within a full European energy system, this study explores early decarbonisation pathways in the hard-to-abate sectors, evaluating outcomes for energy equity, supply security, and sustainability in Denmark under enacted policies. We model 33 European countries using PyPSA-Eur and impose cross-sector carbon budgets from national 2030 commitments to optimise capacity expansion and dispatch of electricity, heating, transport, hydrogen and biomass, including CCS. For Denmark, we apply 9-node spatial resolution and extend the carbon budget setting to include sectoral decarbonisation trajectories, including agriculture. Results show that carbon abatement costs can double if agriculture fails, heating electrification delays, or biomass is diverted from dual use for CCS. System reliability during critical periods relies on thermal storage, strategic biomass use, and flexible electrolysis. Furthermore, early renewable hydrogen adoption may yield export advantages to less decarbonised grids. We recommend: (1) building infrastructure that utilises sector coupling (electrified district heating, CCS, flexible electrolysis), (2) coordinating heat pumps and central heating with CCS to use biomass strategically, and (3) applying comparable carbon pricing across agriculture, heating, and industry, with follow-up actions if voluntary measures fail. While the share of hard-to-abate sectors varies by country, the framework is applicable to other European states with ambitious near-term targets, and the cross-sector dynamics are relevant across national contexts.