In the opinion of a pre-war paper by the British Air Ministry, Germany, as a large producer of synthetic fuel, was thought to be in a favourable position to produce 100 octane fuel in large quantities. The German supply of aviation fuels was largely based on the hydrogenation of coal, due to their limited supplies of natural crude oil. At the outbreak of the war, Germany already had seven destructive hydrogenation plants in operation, with a total installed capacity of 1,400,000 t/year of oil.