Air Force Tells Biofuels Industry to ‘Bring It’

By Grace V. Jean
The Air Force within the next five years wants to be able to go on a shopping spree to snap up several hundred million gallons of alternative fuels produced within U.S. borders.

As the Defense Department’s largest gas-guzzling service certifies its aircraft to fly on 50-50 blends of jet and synthetic fuels, officials are telling industry that it must step up production to meet the expected surge in demand beginning in 2016.

“I’m throwing the gauntlet down to industry,” said Timothy Bridges, deputy assistant secretary of the Air Force for energy, environment, safety and occupational health. “We’re doing our part. We’re asking them to do theirs and support the country as we move toward alternative energies,” he told National Defense in an interview at the Pentagon.  

The Air Force is working to wean itself off foreign oil. It consumes some 2.5 billion gallons of jet fuel annually. By 2030, its intention is to fly on domestically produced alternative fuels concocted from renewable sources including biomass, which encompasses everything from wood chips and plant oils to animal fats and agricultural waste. Those fuels must be cost competitive with petroleum and have greenhouse gas emissions equal to or less than that of oil, officials said.  

“It has to be a business consideration because we want competitively priced fuels for it to make sense to do it,” said Bridges. “Yes, we can get the quantities that we need for the testing, but when it comes to our requirement to actually fly the fleet, that’s a larger challenge. We’re setting the expectations. We want it to be there when we’re ready,” added Bridges, who until recently oversaw energy as part of his responsibilities. A new office dedicated solely to energy was established by the service in November. It is being led by Kevin Geiss, deputy assistant secretary for energy.  

The Air Force has set an interim, mid-decade goal of acquiring half of the service’s annual domestic aviation fuel requirement via alternative blends derived from locally sourced feedstocks. “That amounts to 400 million gallons by 2016,” said Bridges. “We know it takes a while for the infrastructure to be developed to produce that quantity, so we need to send the signals now. If it takes three or four years to build the plant, then we want to make sure that they’ll understand we’ll be ready at the end of that period to actually acquire those fuels.”

The Air Force’s aircraft fleet, ground equipment and vehicles so far have been approved to fly and operate on coal- and natural gas-derived synthetic jet fuel blends. As officials continue to test other samples made from renewable sources and processes, they remain confident that the service will be prepared to buy mass quantities of synthetic and green fuel for operational use. The challenge, they say, is on industry’s end, and they are seeking companies to step up and “bring it.”

“We want to say, ‘Look guys, we’re going to be ready. Will you be ready?’” said Bridges.

That is the question everyone is asking as the nascent alternative fuel industry experiments with turning a variety of feedstocks into fuel. To help industry move along, the Air Force Research Laboratory is testing and certifying as many of those non-petroleum fuels as possible. Officials have taken a drop-in replacement approach. Regardless of whether the fuel was made from corn stover, algae, camelina or animal fats, the end product must function like conventional JP-8 fuel.

“That we’re agnostic to the feedstock and process has really driven people to be really innovative. We’re seeing the benefits of that,” said Jeff Braun, director of the alternative fuels certification office. The initial fuels that have bubbled to the top to lead the pack are processed and blended with traditional JP-8 to attain the necessary chemical properties to power the Air Force’s aircraft, generators and vehicles.

“If you make a 50-50 blend, it really takes a chemist to tell the difference between that and standard jet fuel,” said Tim Edwards, the senior chemical engineer who is leading AFRL’s efforts in the fuels branch. “It looks the same. It burns the same; all the pilots say, ‘I don’t see any difference.’ That’s been the goal,” he said.

Before any flight testing occurs, the researchers collect data on the fuels to ensure that they can be put into the tank without any changes to military hardware or negative impact upon performance. On any given day, trucks pull into the lab’s fuel drum “farm,” or distribution center, to transport thousands of gallons of different fuels to universities and companies across the country for testing and certification in components.  

“There’s fuel going everywhere and we’re trying to help coordinate getting all this testing done to the point where we can get these fuels certified,” said Edwards. “We spend a lot of money, put a lot of man hours into moving fuel around so a lot of data can be collected into research reports to help support that certification.”

So far, the Air Force has certified almost all of its aircraft to fly on a 50-50 blend of jet fuel and synthetic fuel produced through the Fischer-Tropsch process, which converts carbon-based materials into hydrocarbons, or liquid fuels. The process can turn coal, natural gas and biomass into a liquid fuel, known as synthetic paraffinic kerosene. The service in November successfully flew the Global Hawk, a high-altitude robotic aircraft, on a 50-25-25 blend of JP-8, coal-derived fuel from South Africa and natural gas-derived fuel purchased from Shell. The Air Force’s entire fleet early this year will be certified to fly on Fischer-Tropsch fuels, said Braun. Meanwhile, efforts to flight test a second variety of fuel, called hydrotreated renewable jet, or HRJ, continues. HRJ fuels are derived from plant oils and animal fats. In February or March, the Air Force plans to fly the F-22 on it, followed by the Global Hawk later in the summer. The C-17, A-10 and F-15 have already passed their tests.

“There’s still a lot of work to be done, even though things are getting out into the field and they’re flying planes on it,” said Edwards. “We’re firmly looking ahead five to 10 years to what we have to help get into the field then, from the research and development standpoint.”

The popularity of converting biomass into fuel has grown since the Energy Department released a study that found roughly a billion tons of nature’s bounty exists that would not compete with food. Critics of biofuels have argued that planting and harvesting non-edible crops for fuel purposes will undermine traditional farms. But proponents say the nation has much to gain from the practice.

“We’re trying to create more options. Certainly some of those feedstocks will be more expensive than others, so we’re trying to create as many pathways to the same goal as possible,” said Braun.

There are three major groups of biomass that can be used as feedstocks, said Edwards. The first group consists of plant oils and animal fats — the same sources that are now converted to produce biodiesel. The second category comprises sugars and starches, such as those derived from sugarcane and corn, which are used to make ethanol. The third group is known as cellulosic feedstocks, or bio-woody mass, which includes switchgrass, wood chips and agricultural waste. It holds the most promise because of its availability, but the processes to convert the products into liquid fuel are more complicated, said Edwards.

Unlike plant oils and animal fats that have triglycerides that can easily be broken down into diesel or jet fuel-sized molecules, cellulosic feedstocks must first be deconstructed into small enough chunks so that micro-organisms can digest it and turn it into ethanol.

Another approach is to heat the cellulose up until it breaks down into a bio-crude oil and then to convert that into hydrocarbon fuel.

“That’s a fairly difficult process,” said Edwards, who added that he has read papers submitted on the conversion process but has yet to receive fuel samples. The cellulosic feedstocks may make their way into the lab in the near future as a number of entities are actively pursuing it, he added.

For now, the attention has turned to alcohol and a conversion process called oligomerization as the next promising alternative fuel to receive certification consideration from the Air Force.

“If you’re already making alcohols for gasoline, then it makes sense to make hydrocarbon fuels in the same plant,” said Edwards. There are a number of idle ethanol plants already in existence that could be retrofitted to make hydrocarbon jet fuels, he explained. The plants could be adapted to make butanol, an alcohol that is approved for gasoline. It would then be possible to take the butanol and turn it into hydrocarbon jet fuel through oligomerization, a chemical process which strings together multiple butanol units to form molecules of the fuel.

Those same plants could also produce renewable chemicals which could be made into plastics.

“We’re growing a whole new industry there. It’s not just fuel,” Edwards said. “It may be that in some cases, the jet fuel could be the low value product for some of the biorefineries.” For example, a plant may earn $3 per gallon for green diesel, but $15 to $20 per gallon for renewable feedstocks for plastics.

There is also a concerted effort to convert agricultural waste and municipal solid waste products into fuel as well. “If you can make fuel or chemicals out of waste products, that’s really a win-win situation,” said Edwards. “That’s where most of the focus now is.”

At the lab, he and a team of researchers test the fuels that are sent for evaluation and they select the most promising candidates.

“The Air Force’s job isn’t really to pick the winners, because economics and environmental constraints are going to pick those. Our job is to help get as many of those certified to be used as jet fuel and then let the market determine which ones make sense,” said Edwards.

All the work is being done in conjunction with commercial airliners because they fly on the same jet fuel. The Air Force is equivalent to the size of a medium-to-large airline company. “We can’t be the tail wagging the dog, so we’re working closely with commercial aviation through the commercial aviation alternative fuels initiative,” said Edwards. The consortium includes airports, fuel suppliers, airliners and pipeline companies that participate in working groups that are attempting to determine which non-petroleum alternatives will work for commercial aviation. The sector is especially interested in biofuels because of potential carbon tax credits, renewable fuel credits and other policy incentives that would allow airlines to turn more profit. “There’s a lot of money involved … Fuel is their number one single line item,” said Edwards. “There is a lot of urgency that way, both economically and environmentally.”

In 2009, the American Society for Testing and Materials International, which controls the commercial jet fuel specification known as ASTM-D7566, amended the standard to include Fischer-Tropsch fuels. A similar effort to include HRJ fuels last summer failed because members wanted more technical data. The Air Force Research Laboratory provided additional information from its testing efforts and experts were confident that a ballot in December to approve HRJs for commercial use would pass. If approved, the commercial fuel specification could be amended as early as February.

That could open the floodgates, Air Force officials said. While Fischer-Tropsch plants are large and expensive to build and operate, HRJ production facilities are typically smaller and relatively cheaper to run.

So far, there is one full-scale plant operating in Louisiana and several others on the drawing board across the country. Dynamic Fuels LLC, a joint venture between Tyson Food Inc. and Syntroleum Corp., is producing 75 million gallons of green diesel made from surplus animal fats, greases and vegetable oils. The laboratory has received significant quantities of fuel from them, Edwards said.

To conduct its certification tests, the Air Force has purchased a total of 400,000 gallons of HRJ fuel.

Since 2009, the service has spent about $96 million to conduct the testing, said Bridges. “We have been able to get the dollars we need to do the certification,” he said. That funding is expected to continue despite expected rounds of budget cuts in defense spending in the Pentagon. A steady dollar stream will help to keep progress on schedule.

“We have met our goals over the last year, and all indications for this year are that we’ll meet or exceed our goals. We’re doing OK,” Bridges said.

But the renewable fuel production cannot happen fast enough. Defense Department officials are expecting to see an uptick in the Air Force’s recent petroleum consumption numbers. One reason is last year’s Icelandic volcano eruption which disrupted flights to Afghanistan and Iraq. The cargo planes had to fly longer routes, which equated to more gallons of fuel burned, said Sharon Burke, director of operational energy plans and programs for the Defense Department. Number crunching and analysis is ongoing in the office, which is tasked with coming up with a strategy to help change the Pentagon’s energy use.

Burke lauded the department’s investment in research, development, test and evaluation of alternative fuels as part of the solution.

“That’s a smart insurance policy for us because certainly, just like the commercial sector, we look ahead and we see a lot of volatility in the oil market. We have a legacy force that needs to run on something,” she said.  

But the Defense Department is not ready to declare how many barrels of oil it plans to displace with these homegrown green fuels.

“We haven’t done sufficient analysis yet to make a goal like that,” said Burke. “My first focus is on consumption, bringing that down.” But she sees potential for “great flexibility” in biofuels. “They’re an important part of a portfolio that the department is going to be looking at to get energy security for war fighters,” she said.

Air Force officials said that pursuing alternative jet fuels would benefit all military forces on the battlefield because JP-8 is the one fuel that can run both aircraft and ground-based equipment.

That puts increased pressure on industry to produce more alternative fuels, and at a faster pace.

“If you’re not making hundreds of millions of gallons, heading towards the billions, you’re not making a difference, because we use a lot of liquid fuels in the U.S.,” said Edwards. The nation consumes upwards of 20 billion gallons of liquid jet fuel every year.

Still, the efforts to produce and certify 50-50 renewable aviation fuel blends represent a big step for the country.

“What we’re doing now will help enable all 20 to 25 billion gallons a year in 2030 to be fully renewable,” said Edwards.

Until then, the Air Force will fly on available fuels and continue pushing for the alternative supply, Bridges said.

“There are no mandates on alternative aviation fuels,” he said. “It’s a goal we have. We will continue to fly and use the fuels that are available to us. But we’ll continue to work closely with the Defense Logistics Agency’s energy office, so they know it’s a desire of the services, of the Air Force, to have these renewable, alternative, home-grown fuels.”                                           

Topics: Energy, Alternative Energy

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