Gasification technologies enable us to manufacture ultra pure synthetic diesel and jet fuels from biomass, garbage, coal or natural gas. The process is known as Fischer-Tropsch and it has been in steady use since the 1930’s. Ethanol and biodiesel made from food crops such as corn or oil seed are limited in scale and cannot challenge petroleum because we simply cannot make enough through conventional agriculture. F-T fuels are proven at large scales, in fact the challenge today is to enable the manufacturing at small scales so that they can be more widely deployed. Historically F-T fuels have been produced in massive refineries using coal as a feedstock but biomass and garbage are proven to work as well.
The beauty of F-T fuels is that they are perfectly clean, clear as water and with a smell like wax. They contain no sulfur, aromatics, particulates or other impurities.
This picture shows conventional diesel fuel on the left and F-T ultra pure diesel on the right. From Velocys.
This shows what they look like when they burn. Pretty obvious which is better for the environment.
F-T fuels have high cetane ratings and have been tested very successfully by the US Air Force in 50-50 blends with conventional JP-8 jet fuel. Here is a paper that provides an excellent overview of the role F-T fuels can have in the future from an Air Force perspective.
https://www.purdue.edu/discoverypark/energy/assets/pdfs/Harrison08-30-06.pdf
For all the talk of renewables and efficiency folks need to keep in mind that energy strategies for the future must be able to satisfy military requirements. The US Dept of Defense is the largest buyer of petroleum in the world and the Air Force consumes half of it. Of course using oil to fight wars to get oil is a bit circular and unsustainable. Historically though, all of the energy transitions have been driven by military needs. Coal supplanted biomass when coal powered navy ships defeated the wooden sailing ships of old. The coal steamers were in turn defeated by diesel combustion engines. In the future if we want to replace petroleum we need a solution that will enable our military to defeat a petroleum fueled military.
Proof that the synthetic fuels have the performance is shown in the famous 24 Hours of Le Mans auto race. The grueling 24 hour race is a proving ground for advanced technologies. In the last few years turbocharged diesel engines have won every race. And they have been fueled with F-T diesel produced by Shell that is a blend of BTL and GTL, biomass to liquids and gas to liquids.
In 2006 the Audi R-10 was the first diesel to win the 24 hours of Le Mans Race. The Audi team has won every race but one since then. The engines produce “exceptional acceleration, massive torque, and low noise” according to Shell. Diesel engines and F-T fuels have come to dominate the entire race field now.
Here is an interesting document from Shell discussing their synthetic fuels program.
http://www.thecwcgroup.com/UserFiles/Speaker_PDF/1.%20Andrew%20Brown.pdf
The proof is in the performance. Folks can speculate and advocate for various energy solutions but at the end of the day that which works best and is most abundant is what will get used. Your army needs to be able to fight and win battles and cannot run out of gas.
I believe though that engine performance and the environment can go hand in hand. Cleaner fuels reduce emissions and enable higher efficiency performance. We are also not going to run out of hydrocarbons so it’s best we learn to use them in the most effective manner possible.