The Air Force affirmed last summer in an initial feasibility demonstration the Alcohol-To-Jet (ATJ) biofuel is a viable alternative to power the service’s aircraft, according to the head of the Air Force’s alternative fuels efforts.
The November reports from the demonstration are not releasable to the public, but Air Force Alternative Fuel Certification Division (AFCD) chief Jeff Braun discussed the results with Defense Daily yesterday. Braun said the AFCD’s recently completed feasibility demonstration of ATJ in an A-10 fighter jet proved, as he expected, that ATJ is a usable alternative to traditional petroleum, also known as JP-8.
“In other words, this stuff works,” Braun said.
Braun said the AFCD picked the A-10 because it doesn’t burn much fuel and the Division didn’t have a whole lot of ATJ to do the test with. ATJ is an extremely expensive fuel as the Defense Logistics Agency (DLA) purchased 45,000 gallons of ATJ in September at a price of $59 per gallon, DLA spokeswoman Michelle McCaskill said in December. Braun said DLA can buy traditional JP-8 for about $3 or $3.50 per gallon.
Braun said the A-10 was also picked because the Air Force could segregate the two different fuels in different engines, meaning he could put traditional JP-8 through one engine and, at the same time, add their ATJ blend in another engine. This enabled them to do what he called a build-up test, where instead of flying on a pure ATJ blend the first time, the Air Force could get a baseline on JP-8, bring the A-10 down, refill one tank with JP-8 and another with ATJ, enabling the service to compare engines before flying the A-10 on only ATJ.
Braun said the Air Force also did a ground test of the A-10’s TF34 engine at Barksdale AFB, La., where propulsion engineers ran the fuel through a profile to make sure the engine wasn’t going to have any issues. Braun also said before the engine ground test, the Air Force performed a materiel evaluation where they compared the basic TF34 materiel to the fuel system of the A-10 and did a long-term exposure test to make sure there wouldn’t be any abnormal corrosion or wear on the materials.
“It works just like JP-8, which is what we expected all along,” Braun said. “That’s what our lab test and our guys over in the labs told us. They didn’t expect any problems either, but we’re kind of the verification step.”
Due to budget uncertainty, the AFCD is scheduled to stand down March 1 unless the Air Force finds money to keep the alternative fuels certification effort going. The Air Force is currently reviewing the AFCD’s quest for additional funding, but it is up in the air if that money will be found.
Braun said even if the AFCD shuts down due to the lack of funding, the Defense Department’s ATJ certification effort will continue. Braun said the Air Force had partnered with the Army and Navy for ATJ testing and even if the AFCD runs out of money, the Army and Navy will continue testing. Air Force spokesman Ted Theopolos in December estimated the cost to complete ATJ certification at approximately $21 million.
Even though the Army and Navy will continue testing, Braun said the Air Force won’t fall behind because all three services use similar approaches to testing and sharing data.
“Any data that the Navy and Army generate, if the Air Force decides to pick this back up, the first thing we’ll do is grab that data and look at that to figure out ‘Ok, where are the existing holes, where are the gaps that we need to fill as the Air Force,’” Braun said. “Basically, it will be the same approach we were originally going to do, we just won’t be there during the conduct of a lot of that testing.”
Now that ATJ has been affirmed in a feasibility demonstration, there is one more step for the Air Force to take before it officially certifies the fuel to be used in its fleet. Theopolos said he couldn’t answer by deadline whether the Air Force would still be able to officially certify ATJ for use if the AFCD shuts down due to lack of funds.
ATJ is a cellulosic-based fuel that can be derived using wood, paper, grass or anything that is a cell-based material, according to an Air Force statement. The sugars extracted from these materials are fermented into alcohols, which are then hydro-processed into the aviation-grade kerosene used for aviation fuel. The Air Force June 28 for the first time flew a jet, an A-10, on a 50/50 blend of JP-8 and ATJ.
The Air Force has spent a substantial amount of money over the years developing alternative fuels that can be “dropped-in,” or used in any Air Force jet without modifying engines for use. DoD has also encouraged this as a way of weaning the services off of traditional, petroleum-based fossil fuels that are often obtained from adversaries of the United States. Braun said the Air Force certified Hydrotreated Renewable Jet (HRJ) fuel to be used as a 50/50 blend with traditional JP-8 in all jets fleet-wide. Braun also said the Air Force tested HRJ in the fifth-generation F-35 Joint Strike Fighter engine in the “June/July” timeframe and saw no problems with it (Defense Daily, Dec. 19).