Could German refining sustain the diesel fleet?

Would refinery capacity and crude supply limit the usefulness of a German diesel fleet?

Yes, but the counterfactual assumes Germany shifts early investment toward diesel refining and stocks; that makes the fleet more feasible, not unconstrained.

Refining capacity and crude inputs remain major constraints. The counterfactual therefore has to redirect investment as well as select a different engine. Money historically spent developing complex high-pressure steam plants and building fuel-oil stocks would instead support diesel refining and reserves. That choice could leave Germany better prepared for a diesel fleet, but it cannot create unlimited petroleum or protect refineries from attack. Fuel supply remains an industrial trade-off rather than a free source of endurance.