

Pretty sure Nazi Germany powered their industrial base using locally sourced coal.
Some petroleum was supplied from Romania and Iraq, and eventually the Soviets after the pact (1940) until the German invasion in 1941.
Petroleum supplies have always been a key weakness for German self sufficiency.
I wonder if Germany solar farms might improve rates of reindistrialization today.
I’m not certain, but I think that’s a likely possibility. In any case, petroleum supply was a constant concern for the duration of the Nazi German enterprise.
Adam Tooze has a deeper look in this book:
https://ia800401.us.archive.org/24/items/ToozeAdamTheWagesOfDestructionTheMakingAndBreakingOfTheNaziEconomy/Tooze%2C Adam - The Wages of Destruction The Making and Breaking of the Nazi Economy.pdf