SAF A Near-Term Priority For CO2 Use, Say National Academies

National Academies show CO2 utilization
Credit: National Academies

Producing synthetic aviation fuel (SAF) by combining emissions from bioethanol plants with clean hydrogen is one of two near-term priority opportunities identified in a new report on carbon-dioxide utilization by the U.S. National Academies of Sciences, Engineering and Medicine.

CO2 utilization can play an important role in the future net-zero-emissions economy, the report says, and industry and government should begin planning for the deployment of carbon-dioxide utilization infrastructure and processes to transform CO2 into useful products.

“Reaching net-zero will not mean eliminating carbon-based products and systems entirely, but rather ensuring that they are produced without adding net CO2 to the atmosphere,” the National Academies say. CO2 can be utilized sustainably in the manufacture of carbon-based products through chemical conversion.

The report recommends focusing on two near-term opportunities, using off-gases from ethanol plants to produce SAF and mineralizing captured CO2 to produce aggregates for use in infrastructure such as roads and concrete for construction.

Processes to create synthetic fuels and biofuels from CO2 can serve the potential market for sustainable fuels for heavy-duty transportation, particularly aviation, and are a potential means for storage of renewable energy in chemical bonds (so-called Power-to-X).

“Aviation fuel or perhaps marine propulsion are possibly the best uses for synthetic hydrocarbon fuels, since local air quality impacts would be less severe and electrification is difficult due to the low energy and power densities afforded by batteries,” the report says.

“Particularly for aviation, the ability to use existing aircraft and distribution infrastructure together with a decrease in manufacturing costs for synthetic aviation fuel may enable CO2-derived synthetic fuels to be nearly cost-competitive with existing hydrocarbon fuels and other alternative hydrogen options by 2050, if there is a price on CO2 emissions,” it explains.

The report is the first of an expected two by the academies. The second report is planned to evaluate in more detail the potential markets for products derived from CO2 and coal waste; the economic, environmental and climate impacts of CO2 utilization infrastructure; and research, development and demonstration needs to enable commercialization of CO2 utilization technologies and processes.

Graham Warwick

Graham leads Aviation Week's coverage of technology, focusing on engineering and technology across the aerospace industry, with a special focus on identifying technologies of strategic importance to aviation, aerospace and defense.