Some petroleum refineries have been producing diesel fuel from such raw materials as corn, fast food grease, seaweed, algae, and other waste products because the product burns cleaner.

Expanding such production has been inspired by the desire to reduce or eliminate crude oil as a raw material for all fuel production. But is that really smart? The issue is ample supplies of the feedstocks. For example, corn: We are already growing corn to make gasoline, 10% currently, with a plan to increase the content all to 15%. Critics point to the high subsidized cost, pollution from fertilizers and water shortages. Brazil has for some time run their cars on alcohol produced from farm products. The country is under fire for demolishing rain forests to increase farming. Yes, the cars burn cleaner. But the trees are needed to remove carbon dioxide from the atmosphere, and tree planting hasn’t kept up with the clearing activities. We are told that we need to reduce net carbon dioxide, so why is it smart to cut down trees to make fuel?

Why will we need diesel fuel, anyhow, if all cars, trucks and tanks (if still used in warfare) will be electric? Ocean going vessels, those that are not nuclear powered have already transitioned from heavy fuel oil to diesel fuel to reduce atmospheric pollution. What is the plan for ocean-going vessels? Solar panels and batteries? Sails?

Aside from ocean vessels, there are aircraft. Jet fuel is “lighter” than diesel and “heavier” than gasoline. To date, at least one test flight has been reported burning synthetic turbine fuel produced from wastes as described above. Same issues.

It’s easy to pronounce a timeline for ending fuels production from crude oil. The ending part may be neither easy or smart.