Climate change mitigation is a global challenge that, however, needs to be resolved by national-level authorities, resembling a tragedy of the commons. This paradox is reflected at European scale, as climate commitments are made by the EU collectively, but implementation is the responsibility of individual Member States. Here, we investigate 30.000 near-optimal effort-sharing scenarios where the European electricity sector is decarbonized by at least 55% relative to 1990, in line with 2030 ambitions. Using a highly detailed brownfield electricity system optimization model, the optimal electricity system is simulated for a suite of effort-sharing scenarios. Results reveal large inequalities in the efforts required to decarbonize national electricity sectors, with some countries facing cost-optimal pathways to reach 55% emission reductions, while others are confronted with relatively high abatement costs. Specifically, we find that several countries with modest or low levels of GDP per capita will experience high abatement costs, and when passed over into electricity prices this may lead to increased energy poverty in certain parts of Europe