The five billion gallons of fuel consumed annually by the Defense Department is a pittance compared to 200 billion gallons burned nationwide, but the Pentagon is better positioned than most other agencies to lead the way in renewable energy, said Dale Gardner, associate director at the Energy Department’s National Renewable Energy Laboratory, in Golden, Co.
“Since the military can pay a little more per gallon than the airlines or other civilian users, it could serve as a ‘foot in the door’ to get through the technology and implementation challenges,” Gardner said in an interview.
But kicking the fossil fuel habit has been tougher than expected for the military. The adoption of biofuels is a case in point. The Defense Department became an early champion of biofuels, but program managers miscalculated the available supplies. The original plan for the Army, for instance, was to convert its “non-tactical” fleet of sedans and small trucks that are used on U.S.-based posts so they could run on biofuels.
Of the 68,000 vehicles in the Army’s inventory, 40,000 are alternative-fuel vehicles. But just less than 50 percent of those are actually using alternative fuel because the E-85 biofuel is not available in some areas, said Tad Davis, assistant secretary of the Army for installations and environment.
To help government managers make better assessments of alternative fuel options, the Energy Department created an Internet portal called “alternative fuels data center,” said Gardner. It allows users to make calculations that are based on the size and makeup of the fleet. “Each fleet has to be looked at on an individual basis,” he said. “It’s a tool that fleet managers at the Defense Department can use. They can gauge alternatives that are available and make choices, and it shows you the effect of those choices in fuel reduction.”
Gardner said he is optimistic about the military’s forays into the renewable energy world. The lab currently is working with the Air Force office of scientific research on a project to make jet fuel from algae. This is part of a $100 million program funded by the Defense Advanced Research Projects Agency. The goal is to produce a $2 a gallon algae-based synthetic fuel that would be made locally.
The Air Force decided to shift its focus to making synthetic fuel from algae — or other biological feedstocks that do not compete with food supplies — after earlier attempts to develop coal-based synthetic fuel ran into political hurdles.
The coal-to-liquids effort was successful from a technical standpoint, said Gardner. But it was discredited because of the heat-trapping carbon-dioxide emissions that are produced by coal.
Under a 2007 law, the military is banned from buying alternative fuels that emit more greenhouse gases than petroleum-based fuels.
Still, the Air Force should be credited for trying to find ways to help reduce U.S. dependence on foreign oil, said Gardner.
Experts have noted that the coal-to-liquids program seemed like a good idea when oil prices peaked in 2008, but its merits were harder to justify not just because of the carbon emissions, but also for the significant amount of water that is required to produce coal-based synthetic fuel.
Critics on Capitol Hill also chastised the project because of the environmental impact of coal mining on mountains.
It could be years or decades before synthetic fuels become mainstream in the Air Force. In the near term, the service is pursuing other means to lower consumption. One is the use of winglets on the tail of some of transport aircraft, said Alan Shaffer, acting director of defense research and engineering, during a hearing of the House Armed Services Committee’s readiness subcommittee.
“Under certain circumstances, winglets can increase energy efficiency by 10 percent. That’s significant,” he said.
The Air Force is also seeking ways to make its turbine engines more efficient. Under a program called “versatile affordable accelerated turbine engine,” the Air Force believes it can achieve 25 to 30 percent more energy efficiency, said Shaffer. “The Air Force really looks like they’re on the verge of making some breakthroughs in turbine engines.”
Shaffer said his office will be reaching out to government and industry for new ideas. The Defense Department’s renewable energy program is expected to benefit from the Obama administration’s policies aimed at reducing U.S. dependence on imported oil. The Pentagon recently received a $300 million boost for energy-related research projects as part of the stimulus spending bill that Congress passed in February. Those funds will be added to the $1.3 billion budget that already had been approved for Defense energy programs for fiscal year 2009.
The Pentagon also has sought advice from the CIA-sponsored In-Q-Tel venture capital firm that invests in high-tech companies. “We asked for energy solutions,” said Shaffer.
Adapting civilian green technologies for military use is not always easy for the Pentagon.
One example is a project designed to turn mess-hall garbage into jet fuel — known as “tactical garbage to energy refinery.”
The Pentagon shipped to Iraq two prototypes of the garbage-to-energy units in May 2008. They were tested for 90 days and the results were disappointing, officials said.
“I wish I could tell you that they have worked as well as advertised. They did not,” Shaffer told the readiness subcommittee.
“The goal was to operate this system for 20 hours a day at a forward operating base with a battalion. We made the assumption that it would be four pounds of trash per person per day,” he told lawmakers.
A unit of 500 soldiers is estimated to produce about a ton of trash a day. That ton of trash would have turned into 100 gallons of JP-8 fuel, which would have powered a 60-kilowatt generator for 20 hours. “That increases the security of our forces [because] we don’t have to use our forces or contracted forces to guard trash,” said Shaffer.
But the refinery only ran four to six hours a day before dust and dirt would cause it to stop operating, he said.
Garbage-to-energy converters work better in fixed locations, he said. The Army recently convened a group of experts at Aberdeen Proving Ground, Md., to develop a strategy for how to use this technology.