It's August! Already?
In the just released, U.S. budget bill, money was included to provide a tax credit for Sustainable Aviation Fuels. The hope is that this credit will help spur the commercialization of sustainable aviation fuels. I have written here in the past about the differences between "sustainable" and "synthetic" aviation fuels and will not belabor them here. In the case of the U.S. budget bill, "SAF" is the sustainable fuel, which is a subset of the synthetic fuel. While great strides are being made in the aviation industry on hybrid aircraft, electric aircraft, even hydrogen aircraft, the fact remains that liquid fuels produced from sources other than petroleum are likely to be the most attainable in the near term. Whether this is liquid fuel produced from agricultural sources, green waste, algae, or yellow grease, these are all approved pathways for the production of a drop-in liquid hydrocarbon fuel that complies with the U.S. ASTM specification, D1655. The technical people have done their jobs; a fuel that is compliant with ASTM D7566 reads across to ASTM D1655, Jet A. Once that happens, technically it meets the needs of the aircraft. At that point it is up to the industry to produce sufficient quantities to supply the aviation gas turbine aircraft market.
In the meantime, work continues on new ways to produce liquid fuels, to power aircraft, and to design more efficient power plants, and even to design aircraft with non-liquid fuel requirements. Some people say the aviation industry moves too slowly, that "it doesn't care about the environment and the future", or that "all the industry cares about is profits!" Just remember, that when your Tesla loses power, you coast to the edge of the road, curse, and call AAA, in some order. But if an aircraft loses power, coasting is challenging, the edge of the road is 30,000 feet below you, and there is no AAA. From the inside, I promise you the industry is moving at an incredible speed, all tempered by our commitment to safety.