Domestic and global trends in energy security and corporate responsibility have encouraged many public- and private-sector organizations to commit to adopting biobased aviation fuels. Biorefineries and airlines have demonstrated significant interest by signing long-term purchase agreements. Currently, the United States has three operational facilities that produce biobased aviation jet fuel and/or green diesel. Five additional facilities are planned in the near future.

In addition to those 8, LanzaTech is developing additional pilot-scale plants, including a facility for alcohol-to-jet (ATJ) in Soperton, Georgia. LanzaTech has partnered with Boeing, Virgin Atlantic, General Electric, and Pacific Northwest National Laboratory (PNNL) to develop and commercialize their ATJ (Alcohol-to-Jet) processes.

Other developers committed to pilot- and demonstration-scale operations in the United States, such as Gevo, have included jet fuel products as part of their portfolio. Recently, Gevo signed an offtake agreement with Lufthansa to supply up to 40 million gallons of ATJ over a 5-year period.

Five alternative jet fuel (AJF) pathways have been certified by the ASTM D7566 process: FT-SPK, HEFA-SPK, HFS-SIP, FT-SPK/A, and ATJ-SPK. A maximum blending level has been identified for each of these, with levels ranging from 10% up to 50% blending level, driven by the properties of each of these blending streams to meet the D7566 specification requirements.

There are seven additional pathways in the queue for the D7566 process:

1. Catalytic conversion of sugars by aqueous phase reforming (CCS-APR)

2. Catalytic hydrotreating of lipids (catalytic hydrothermolysis [CH])

3. Pyrolysis (hydrotreated depolymerized cellulosic jet [HDCJ])

4. Co-processing biocrude

5. Catalytic upgrading of alcohol intermediates (catalytic ATJ-synthetic kerosene with aromatics [CATJ-SKA])

6. Catalytic upgrading of ethanol (ATJ-SPK expansion)

7. HEFA expansion

More than 15 other different pathways have been identified as part of the pre-pipeline for production of AJF.

Despite the approval of these conversion pathways, technical, social, and regulatory barriers have limited both the production and the growth of the industry. To better understand these barriers and to help develop a potential research, development, and demonstration (RD&D) strategy to further support the development of bio-derived jet fuel, BETO held a workshop to engage stakeholders and to gain further understanding about challenges and opportunities related to aviation biofuels, including the following:

• Advance progress needed to achieve affordable, scalable, and sustainable production of aviation biofuels.

• Increase the economic and technical competitiveness of aviation biofuels from lignocellulosic biomass.

• Enhance the environmental and sustainability bene ts of aviation biofuels.

• Ensure robust feedstock and product supply chains to support the development and deployment of aviation biofuels.

Key findings from the plenary presentations include the identification of common characteristics of successful alternative aviation fuel production. These include the need to make fuel of sufficient quality for desirable blending impacts; ensuring the execution of proper scale- up approaches and techniques; and forward-looking methods for achieving higher profitability and maintaining competitiveness of the bioenergy industry. The stakeholders’ discussions also emphasized the importance of stable government policies necessary for the continued growth of the bioenergy industry.

Outcomes included recommendations for BETO to continue to work collaboratively with existing organizations, such as the Commercial Aviation Alternative Fuels Initiative (CAAFI) and Federal Aviation Administration (FAA), as well as to organize a stakeholders’ working group across the supply chain to inform the development of these analyses.

Further recommendations are that analyses should consider both forward-focused projections of these technologies, which have been scaled and de-risked (the N^th plant approach), and near-term, early-adopter economics. From the nearer-term considerations, the analyses can help identify the biggest scale-up risks and barriers for a technology, thereby informing further research and development (R&D) considerations for both DOE and industrial stakeholders.

Technical barriers for alternative jet fuel (AJF) pathways ranged from a lack of availability or access to equipment, low-cost feedstocks, capital, and experts for biofuel production scale-up to the expense and time required to move a process through the ASTM certification process. The lack of publicly available and/or reliable data for evaluation of these technologies was also identified as a limitation.

Outcomes included identification of more than 20 pathways for future consideration, recommendations for the roles DOE can play in aviation fuels RD&D, and scale-up of the production of biofuels and key co-products from bench to pilot and demonstration scales. Finally, participants deemed it essential that DOE support initial evaluations to obtain a set of baseline data for these emerging process strategies so that reliable and comparable evaluations could be developed.

Resources

• Alternative Aviation Fuels: Overview of Challenges, Opportunities, and Next Steps