The situation demands action, and action is on its way. As the gap between petroleum-based fuel production and demand continues to widen, the aviation industry has become active in its search for a viable fuel alternative. While great progress in alternative fuel development has been made during the past few years, U.S. industry has yet to see anything new on the market. Some innovative companies, however, are looking to change that as soon as possible. Who will bring their new and improved fuel into commercial use first, possibly ending petroleum-based fuel consumption in the skies forever?
The ideas for alternative aviation fuel are abundant, but only a handful are feasible for immediate production and consumption. Alternative fuels can be placed into three categories: synthetic fuels; bio-fuels; and hybrid, electric, or hydrogen fuel technology.
In order to utilize hydrogen fuel technology in aircraft, major engine and airframe modifications must be made, including the adoption of a large, heavily insulated hydrogen fuel tank. On top of that, the entire fuel supply infrastructure would have to be switched out.
Hydrogen technology could be the best solution for long-term sustainability, but it does have drawbacks. While burning hydrogen is clean, hydrogen is currently produced from natural gas or other hydrocarbons. CO2 is released as a byproduct of this conversion process. However, the hydrogen production CO2 quantity is less than the CO2 produced from a gasoline powered car by approximately 50% - a significant improvement. New hydrogen production technologies under study offer hope of a cleaner, more efficient production.
The more viable options lie in the realm of synthetic and/or bio-fuel blends which can directly replace (drop-in) petroleum-based fuels without any modification to either aircraft or fuel supply infrastructure.
Approval for these fuels, however, is another story.
VYING FOR APPROVAL
Alternative fuel candidates must pass stringent specification requirements in order to assure the safe and reliable operation of aircraft. The “high hurdles” that aviation fuel must overcome are considerably more rigorous than fuel for ground transportation because of the different set of safety criteria for aircraft.
Nancy Young, Vice President of Environmental Affairs at the Air Transport Association (ATA), says that working with companies and airlines which are developing alternative fuels is critical so that everyone involved is speaking the same language regarding the end product.
“It’s even more critical to the airlines that we be involved and encourage suppliers that if they make it through the [certification] process, that we will be there to buy their product,” says Young.
“That’s part of what ATA is doing as a founding and principle member of the Commercial Aviation Alternative Fuels Initiative (CAAFI).”
CAAFI was established to aid in the exploration, development, and certification of alternative fuels. The organization includes a range of participants from the international commercial aviation community.
“CAAFI works with FAA in order to help in the certification, qualification, and the research and development of alternative aviation fuels,” says Hank Price of the office of communication for environment and energy at FAA.
“Our major goal is a fuel than can offer equivalent levels of safety and is comparably favorable to petroleum-based jet fuel, both on cost and environmental effects.”
Price admits that the industry must first approve an alternative “drop-in” fuel which will be gradually replaced by more efficient and environmentally friendly fuels as they are developed.
Some specific requirements for alternative aviation fuel include: smooth boiling range distribution; high energy output; thermal conductibility; storage stability; and freezing point, just to name a few.
ASTM International, an organization which develops technical standards for design, manufacturing, and trade in the global market, has approved only two types of jet fuel for commercial use: the standard petroleum-based fossil fuel we use today, and a synthetic fuel produced by the South African company, Sasol.
This program will work to provide loan guarantees for construction of commercial-scale alternative fuels production facilities.