Since 2018, the Austrian Academy of Sciences has regularly organised a so-called Joint Academy Day together with one or more academies of sciences abroad. [...] The idea of joint academy days is simple: The OeAW, both the so-called learned society as well as its research institutes, aims to intensify contacts and forge bonds with other academies in order to strengthen alliances through lectures, discussions, and personal exchange of ideas on a specific topic. Today and for the first time, the Joint Academy Day is held with an academy alliance, the European Academies’ Science Advisory Council EASAC. [...] EASAC’s visit in Vienna also marks the starting point for a strong cooperation between the OeAW and EASAC. [...] As for today’s topic of our Joint Academy Day, we quickly agreed on one of the most pressing issues of our time, sustainable energy solutions. It is a highly topical issue we chose, not only for both our institutions, but also for Europe and the whole world. [...] This Joint Academy Day will start off with a keynote lecture by EASAC’s president Wim van Saarloos followed by a panel discussion about energy transition, realistic ambitions and ambitious perspectives with experts from both EASAC and the OeAW, that will certainly address these themes and the political measures to manage the energy transition quickly as well as successfully.