CAAFI is the Commercial Aviation Alternative Fuels Initiative, a cooperative effort among interested stakeholders to bring commercially viable, environmentally friendly alternative aviation fuels to market. CAAFI is co-sponsored by the Aerospace Industries Association (AIA), Airports Council International - North America (ACI-NA), the Air Transport Association of America (ATA) and the Federal Aviation Administration (FAA). In addition, CAAFI consists of approximately 300 non-sponsor stakeholders. These include members of other U.S. and non-U.S. government agencies and trade associations, as well as energy producers, university faculty, nongovernmental organizations and consultants. CAAFI functions as a clearinghouse, facilitating the exchange of information about and coordination of private-sector and governmental initiatives supporting the development and commercialization of "drop-in" alternative aviation fuels (i.e., fuels that can directly supplement or replace petroleum-derived jet fuels). CAAFI is also exploring the long-term potential of other fuel options.

CAAFI was formed in 2006 in response to three concerns regarding aviation fuels: 1) supply security, 2) affordability and price stability, and 3) environmental impacts. These concerns prompted the FAA Office of Environment and Energy R&D Advisory Board to request action on aviation alternative fuels from the FAA Office of Environment and Energy. Following initial presentations by the manufacturing sector and the U.S. Air Force at a Transportation Research Board (TRB) forum in January 2006, FAA, ATA and AIA elected to form a coalition of interested parties, later formalized as CAAFI; ACI-NA joined shortly thereafter.

CAAFI aims to facilitate the development and deployment of alternative aviation fuels that will significantly reduce emissions associated with aviation operations in commercially meaningful quantities to improve price stability and supply security. The environmental goal applies to all emissions but, in particular, the availability of alternative fuels will help aircraft manufacturers and operators reduce aviation's carbon footprint, even as aviation returns to projected growth levels.

CAAFI is organized in four functional teams: research and development (R&D), certification and qualification, business and economics, and environment. All sponsors and stakeholders contribute to the panels in their areas of expertise. The four teams ultimately are governed by an executive director and a steering committee, which includes the four team leaders and representatives of each of the four co-sponsors. Organizations conducting critical CAAFI research efforts may participate as observers. While the executive director is under contract to FAA, all other CAAFI functions are supported by coalition members.

With established functions and recognized leaders, as presented on http://caafi.org, CAAFI teams are unified and able to take advantage of opportunities in existing forums (e.g., ASTM for certification and the ATA Energy Council for business and economics). Representatives from more than a dozen federal agencies, as well as Canada, Mexico and the European Union, play complementary roles and take on significant responsibilities. CAAFI has benefited from its small size, unity of purpose and technical capability, with all participants sharing in CAAFI victories.

• Fuel Specification Approvals. Before aircraft can use alternative fuels, those fuels must meet rigorous criteria spelled out in aviation fuel specifications and fit-for-purpose criteria. The CAAFI certification and qualification team works within established processes to help move promising alternative aviation fuels through to approval. Government agencies, fuel manufacturers, aircraft and engine manufacturers and airlines are stakeholders in CAAFI, and many participate on the certification team. CAAFI certification requirements specify that these alternative fuels should be "drop-in" to pipelines, fuel farms and all other distribution and storage channels, thus requiring no new equipment or infrastructure. In August 2009, ASTM International, the relevant standard-setting organization, approved a new fuel specification, ASTM D7566, "Aviation Turbine Fuel Containing Synthesized Hydrocarbons." This specification allows for alternatives that demonstrate that they are safe, effective and otherwise meet the technical and fit-for-purpose requirements to be deployed as jet fuels. The initial issue of the specification enables use of fuels from the Fischer-Tropsch (FT) process up to a 50 percent blend with conventional Jet A. The ASTM D7566 specification is structured, via annexes, to accommodate different classes of alternative fuels when it is demonstrated that they meet the relevant requirements. The specification was developed by an ASTM Synthetic Fuels Task Force, a group that includes many CAAFI members. This is a crucial step on the road to aviation alternative fuel approval and deployment. The ASTM approval of synthetic fuels took less than 20 months from the initial flight program of natural gas-to-liquid fuels on an A380 and less than two years from initial U.S. Air Force testing on a B- 52.


• Fuel Readiness Assessment. As a means of articulating the status and readiness of technology for processing and feedstock technology funding sources, CAAFI has created a "fuel readiness scale," which identifies the status of technologies from concept (FRL 1) through full-scale production (FRL 9). This process was developed with the U.S. Air Force and has been circulated internationally for possible use in coordinating efforts and communicating to research facilities globally. This process and the technology roadmaps that accompany it take maximum advantage of the recognized strengths of our industry in managing risk and executing at the system level.

CAAFI continues to educate public and private interests on the unique needs and practical solutions for developing alternative aviation fuels. In addition to creating roadmaps for alternative aviation fuels that communicate aviation needs, solutions and actions, CAAFI is developing a handbook for calculating environmental and economic benefits and costs of alternative fuels for airports. CAAFI is also working to improve the understanding of life cycle environmental impacts of the production and use of alternative fuels, and supports R&D on low-carbon fuels sourced from renewable feedstocks such as plant oils, algae and biomass.

• Fuel Certification. CAAFI is disseminating flight-test information on synthetic fuels and biofuels, and working to attain certification for their use. As a result of the recent ASTM decision to remove specification barriers to alternative aviation fuels, talks on possible production contracts between producers and buyers are already underway. While these commercial discussions are ongoing, significant volumes of alternative aviation fuels are not likely to be in the pipeline for another three years. If successful, in five years, the construction of three currently planned Fischer-Tropsch facilities producing 30,000 barrels per day and 10 projected HRJ facilities producing 6,500 barrels per day could meet about 4.2 percent of this country's annual jet fuel demand of approximately 22.8 billion gallons (for U.S. carriers and general aviation). This would be a good launch point to achieve the IATA goal of 10 percent by 2017 for commercial aviation.


• Environmental Profile. Producers share a concern with buyers about a consistent definition of appropriate life cycle analysis methodology, an area CAAFI is strongly promoting in collaboration with the MIT PARTNER Center of Excellence.


• Project Financing. The biggest remaining challenge to the deployment of alternative aviation fuels is financing of large-scale projects that encourage producers to provide feedstocks and dedicate resources to aviation. Promotion of these projects entails overcoming the barriers of the current investment environment and the characteristics of aviation, which has unique distribution channels and carries less than 10 percent of the total transportation fuel market share. Financing will become more achievable as the cost of production is reduced through manufacturing technology. Thus, aviation alternative fuels are quite similar to other industries' development. It requires a combination of advance process development for specific feedstocks (e.g., algae water extraction) and engineering (e.g., cooling-water requirements and reduced gasifier costs for FT plants). In the case of more advanced fuels (cellulosic fuels, fermentation and pyrolysis processes), there remain technical steps to be taken to achieve a fuel within the range of required characteristics for certification.

Alternative aviation fuels activity had been developing slowly since the 1970s, largely through the efforts of the U.S. Air Force and a group of engine companies. When CAAFI emerged, the ASTM committee had begun the process of streamlining their certification processes for new aviation fuels. However, only one production facility, a coal-to-liquid plant in South Africa, had been able to achieve approval, and that took nearly 10 years and $30 million. A blend of synthetic and conventional jet fuel produced by the South African producer Sasol was approved by ASTM and has been in service for approximately six years on flights in and out of Johannesburg. In 2008, the use of neat Sasol synthetic fuel was approved as well. Approval of the new ASTM D7566 specification for synthetic aviation fuels, with the ability to add annexes to it for new alternatives once proven, brings the true dawn of the era of alternative aviation fuels.

CAAFI is confident that environmentally friendly alternative jet fuel derived from several feedstocks will be available in the next two to five years. The types and volumes of alternatives reaching the marketplace will depend on many forces, including the extent of governmental support, new technological developments and investor interest. CAAFI is both feedstock-neutral and technology-neutral; that is, it does not support certain technologies or feedstocks to the exclusion of others but rather seeks to facilitate conditions in which alternatives can thrive and compete openly within the bounds set by policymakers and the marketplace.

Of the current options, synthetic liquid fuels manufactured from coal (such as the fuel from Sasol), biomass or natural gas (or combinations thereof) are viable, nearly identical replacements for kerosene. The U.S. Air Force plans for its entire fleet to run on fuels that are at least 50 percent synthetic by 2016. IATA has a goal of 10 percent of airline fuel from renewable biojet by 2017. Jet fuel made from agricultural oil crops by a similar hydrotreating process is likely to be viable by the end of 2010 and will contribute to meeting both of these goals. Biojet fuels from other processes (fermentation or pyrolysis) or feedstocks, such as algae, are deemed a midterm option, as production capacity challenges are being addressed. However, recent focus on renewable fuels may stimulate innovation and accelerate the introduction of these fuels. Ethanol does not appear to be an option for transport aircraft but may be relevant to general aviation. Hydrogen is a very long-term option, depending on technological developments and potentially prohibitive infrastructure investment.

• Greenhouse Gas (GHG) Emissions
  
  • Fischer-Tropsch Fuels. Because synthetic fuels are slightly lower density on average than Jet A, they may offer some reductions (~1-2 percent) in CO₂ emissions in the operational phase. In the production phase, the coal-to-liquids FT production process yields a larger CO₂ footprint than traditional production processes. However, carbon capture and sequestration (CCS) can reduce that footprint to a level equivalent to that of a traditional oil refinery. Supplementing CCS by incorporating biomass can offer carbon life cycle levels well below that of a traditional oil refinery. CCS has been proven in some application. For example, deep saline aquifers have been in use as a storage medium, while in-ground storage requires further development and regulatory acceptance as a means to successfully address carbon emissions.
  
  
  • Hydrotreated Renewable Jet (HRJ) Fuels. Life cycle emissions from HRJ fuels are highly dependent on the feedstock and the land-use change associated with it. Studies have suggested that, HRJ from palm or soy oil can have as little as half the emissions of conventional Jet A, assuming no land-use change. However, land-use change can be critical with any biomass, as converting tropical or peatland rainforest to biomass production can increase the life cycle emissions by several orders of magnitude over that of traditional Jet A. HRJ production requires high-yield feedstocks that do not require arable land. Potentially suitable feedstocks include jatropha, camelina and, to the extent oil-extraction techniques are improved, algae. Such alternatives could have improved life cycle emissions on the order of as much as 80 percent, if land use and other production issues are appropriately addressed.


• Local Air Quality Emissions. Synthetics contain little or no sulfur and no aromatic compounds. Thus, when blended with traditional fuel, sulfur and aromatic content is reduced. Such fuels may produce less particulate matter (a growing concern for local air quality). Also, because synthetics have fewer tendencies to decompose, such fuels could allow for more fuel-rich combustor design options that could reduce emissions of nitrogen oxides.

Many studies, such as those from Princeton, Noblis and Scully Financial, have shown FT fuels (subject of initial certification action) are viable at current oil prices, to the extent that commercial-scale production is achieved. The barrier to deployment in this case is availability of capital, as the plants cost on the order of $100,000 per barrel per day. HRJ plants are much less capital-intensive but are 80-85 percent dependent on feedstock cost for recurring costs. Hence, a sustainable business model that improves yields and encourages the growth of energy crops is required to ensure competitive costs. In the long run, alternative fuels are necessary for economic and ecological viability of commercial aviation. All of the parties involved in CAAFI understand that being the first transportation mode to move forward with alternative fuels will help ensure aviation's economic viability and environmental acceptability.

Effects can be positive or negative. For example, lower density fuels can improve fuel burn but adversely affect payload range. The current fuel alternatives can absorb more heat than existing fuels an important factor for newer aircraft with more electronic equipment. CAAFI is exploring all performance impacts.

Benefits to airports are possible with alternative fuels. To the extent that airlines have access to environmentally beneficial alternative fuels for aircraft, the emissions associated with airline flights may be reduced on a life cycle basis. Airports that own and operate ground service equipment can also see environmental improvements in their operation of their own equipment, as alternatives for such equipment can reduce greenhouse gas and local emissions as well. A handbook to evaluate costs and benefits at airports is under development via Project 02-07 of the Airport Cooperative Research Program (ACRP).

Questions & Answers from the Air Transport Association of America give detailed information on alternative jet fuels.

Last Updated: 10/19/09