Which Energy Solidarity Union?

The Russian invasion of Ukraine caught the European Union (EU) off-balance. Many European member-states were, on the onset of the war, heavily reliant on energy supplies provided by Russia. Against this background, some have proposed a unified approach for the creation of EU-wide strategic energy reserves, which would ensure a buffer against future energy shocks, but also provide temporary relief to the participating countries should some of them experience temporary issues with their energy supply. However, the political feasibility of such programmes remain disputed, as any EU-wide approach to energy will entail both additional financial costs and a share of responsibilities and sovereignty on the matter. Furthermore, any such policy design is inherently multidimensional, differing over scope, governance, source of financing among other dimensions. To determine public support for energy security cooperation, we conduct the first conjoint experiment ever fielded on public support for alternative energy union design. We field a pre-registered, randomized conjoint experiment on a highly representative sample of the French, German, Italian, Dutch and Spanish population in November 2022. This multidimensional conjoint experiment allows us to determine the causal link between policy features of potential energy solidarity pacts, and public support or opposition to such policy. Our results show that policy packages meeting the most support require higher levels of ambition, joint EU-level governance, joint purchases and procurement, and progressive taxation as a form of financing. All in all, our results not only show that there is considerable cross-border support for energy solidarity, but also that citizens in different western European countries have generally converging preferences regarding the actual design of such policy, indicating that a compromise policy is feasible and publicly supported. Furthermore, our results support ongoing research on the nature of European solidarity at times of crisis, suggesting that European citizens are willing to support the creation of joint institutions and policies to face issues of common concern, and therefore indicating that major crises open important windows of opportunity to re-shape EU-level policies and institutions.