2040 greenhouse gas reduction targets and energy transitions in line with the EU Green Deal

The European Green Deal aims to guide the European Union towards achieving net-zero greenhouse gas emissions by implementing a comprehensive set of policy initiatives and legislation. While emission reduction targets and policies up to 2030 are mostly implemented, it is of high priority for EU legislation to spell out the further transformation to climate neutrality by defining interim policy targets for 2040. To provide information for this target-setting process, we use an integrated energy-economy-climate model with high sector detail to explore pathways to achieve climate neutrality in the EU under uncertainty about key energy system developments. Results suggest that emission reductions of 86% (sensitivity range: 80% to 93%) by 2040 relative to 1990 are consistent with a cost-efficient distribution of mitigation efforts over time, substantially exceeding the 78%-level implied by a linear interpolation between the 2030 and 2050 targets. Additionally, we identify a 7-fold (sensitivity range: 4-8-fold) upscaling of electricity generation from wind and solar, a 49% (sensitivity range: 45-59%) share of electricity in final energy supply and an upscaling of carbon capture and storage (CCS) to 188 Mt CO2/yr (sensitivity range: 56-257) as crucial transformation milestones for 2040.