At the end of 2025 the European Union’s 66 mainstream refineries had a combined primary refining capacity of 567.4 million tonnes a year, and the 72 mainstream refineries of the EU, the United Kingdom, Norway and Switzerland together had 625.4 million tonnes. Those figures describe installed plant, not the fuel that plant can deliver in a given quarter. Refineries are periodically shut down, in whole or in part, for statutory inspections and maintenance: at Porvoo, Finland’s only mainstream refinery, Neste now plans such a turnaround every two and a half to three years, and the one completed in June 2024 cut the refinery’s utilisation to 34% for a quarter. A planned stop can also become an unplanned one. In June 2022 the crude oil distillation unit at Schwechat, Austria’s only refinery, was damaged during a legally required pressure test in the final stage of a turnaround, and the refinery did not return to full operation until 7 October. By the autumn of 2026 European refineries were running close to maximum capacity while diesel and jet fuel prices stayed high, the European Commission had asked member states to defer non-emergency refinery maintenance, and senior figures at NATO and the Commission had linked fuel supply to defence. Rearmament adds a claim on an industrial system whose capacity is only partly available at any given moment. What has to be in place, at the same time, for Europe’s refining capacity to remain usable while it is being maintained?