Can the U.S. military move to renewable fuels?

By Sohbet Karbuz | October 31, 2008

In a 1906 planning document, the U.S. War Department imagined, “In 1950, the U.S. military [will be] a highly effective, mobile, and mutually supporting force, protecting all required American interests through dominant air, land, and sea operations powered by a petroleum energy standard that is reliably and economically produced from domestic sources.”

That vision came true except regarding the last two words. Oil production in the United States, the largest producer in the world at the beginning of the 20th century, reached its peak in 1970. Today, the United States is the world’s largest oil importer, and the U.S. military is the single largest consumer of oil in the world. (For more detail see War Without Oil: A Catalyst For True Transformation.)

From the end of the Cold War to the first years of the 21st century, the Pentagon’s energy consumption dropped by some 40 percent, but with the “Global War on Terror,” consumption has risen again. Oil fuels the U.S. military’s nearly 11,000 aircraft and helicopters, 200 combat and support ships, 200,000 tracked and wheeled vehicles, and 190,000 non-combat vehicles, such as trucks, passenger cars, and buses (not to mention many unmanned aerial vehicles and missiles).

Although fuel costs represent less than 3 percent of the Defense Department budget, indirect costs such as those for transporting fuel to battlefields and distributing it to the end-user, add to the total. When the cost of the army’s entire logistics network is added to the cost of delivered fuel, gas prices are $13-$19 per gallon. In the air force, these costs can be much higher, military grade jet fuel delivered through aerial refueling costs upwards of $42 a gallon.

The military is aware of its dependence on oil, and is working to increase its energy efficiency and to create viable alternative fuels such as biofuels and synthetic liquid fuels from natural gas and coal. Rising energy prices necessitate the change even more. In 2008, the Pentagon’s bill for energy will total roughly $15 billion. The Pentagon has requested $3 billion more for fuel for 2009 than in 2008, and oil accounts for almost 80 percent of the military’s total energy bill. The U.S. military estimates that each $10 per barrel increase in the price of oil costs the U.S. government an additional $1.3 billion dollars.

Developing a solution?

The peaking of global oil production, which is expected to occur in the next few decades, will mark the beginning of the end of the oil age and will have serious implications for the U.S. military.

The Defense Department has already become a leader in some areas of renewable power. The U.S. Navy is powering its base in Guantanamo Bay, Cuba, with a 3.8 megawatt wind/diesel hybrid plant, the largest in the world. The Naval Air Weapons Station at China Lake, California, uses a geothermal energy plant (built in the 1970s) and is a net contributor to the local commercial electric grid. A project being tested at the Diego Garcia Naval Base in the Indian Ocean will generate electricity from temperature differences between the ocean’s surface and deep water. And a 14.2 megawatt photovoltaic array, again the largest in the world, became operational at Nellis Air Force Base in Nevada in December 2007.

The air force, the largest renewable power purchaser in the United States, relies entirely on renewable energy to power four of its bases, while several other air force bases use a combination of solar, wind, and landfill-emitted biogas production for power. (But most of this comes from purchases of renewable energy credits rather than onsite resources or purchases of green power.)

Further gains in the military’s use of renewable energy technologies and the purchase of electricity generated from renewable sources should come from the National Defense Authorization Act of 2007, which mandated that the Pentagon produce or procure 25 percent of its facility electrical consumption from renewable sources (but failed to include a target year). Current projects include the Defense Advanced Research Projects Agency’s investigation of using waste materials (such as paper, plastics, cardboard, ammunition papers, food-slop, etc.) as fuel and the army’s development of hydrogen fuel cells and renewable energy hybrid-electric generators for use at forward operating bases and remote locations. Fuel-saving technologies under development include the army’s foam-insulated tents and biodegradable domes that take less energy to heat and cool, the air force’s synthetic fuels and on-site biomass and waste energy projects, and the navy’s research into using nuclear power throughout the fleet.

Short-sighted eco-friendly energy policy

It is a pity, however, that most of the Pentagon’s efforts are concentrated on generating electricity, which accounts for less than 12 percent of military energy consumption, and not on oil, which accounts for more than 75 percent. Since only liquid fossil fuel can power the military’s vehicles for the foreseeable future, the Pentagon is focused on using biofuels such as ethanol and biodiesel and synthetic fuels as potential replacements. Defense is actually one of the largest customers of the U.S. biofuels industry representing nearly 10 percent of the ethanol market and 0.6 percent of the biodiesel market.

Nevertheless, biofuels supply only 0.1 percent of the Pentagon’s total vehicle fuel demand. Besides cost issues that prevent widescale adoption, biofuels have been found to gel and clog aircraft engines at high altitudes and when temperatures decrease. The use of biodiesel in ships is currently prohibited due to possible damage to engine fuel system components in the presence of water (since biofuels are hydrophilic, rather than hydrophobic as is gasoline, which contributes to part corrosion, accelerates fuel storage instability, and affects the fuel’s cold weather operating properties). Also the use of biodiesel in military ground combat vehicles is prohibited due to questions over the long-term stability of the fuel, its tendency to gel in cold weather, and other concerns.

The air force, the U.S. military’s leading consumer of oil, is spearheading the evaluation, support, and testing of synthetic fuels and engine technologies. It has good reason, the rate that fighters, bombers, and other vehicles consume oil is so high it is often given in gallons per mile or gallons per hour or minute instead of miles per gallon. For example, the B1-B Lancer, a bomber, burns about 59 gallons per minute; the B-52 Stratofortress burns about 54 gallons per minute; the KC-135 (an aerial refuelling tanker, known as a flying gas station) burns on average 35 gallons per minute; and the F-16 Falcon fighter burns about 13 gallons per minute.

Defense and the Energy Department are working together to develop, test, and certify jet fuels derived from coal and natural gas (via the Fischer-Tropsch process [FT], developed by German researchers in 1923 and used by Germany and Japan during World War II to produce alternative liquid fuel to conventional oil), and oil shale. Production of jet fuels from these sources is feasible, but a number of technical hurdles remain. These include improving the lubricity, storage stability, and perfecting their combustion performance.

The first synthetic fuel (or synfuel) tests were run on B-52s. The first B-52 flight using a synthetic fuel-blend jet fuel (50 percent from natural gas and 50 percent from conventional crude-oil) occurred in September 2006 at Edwards Air Force Base in California. In March, a B-1B Lancer became the first U.S. military aircraft to fly at supersonic speed using a synfuel blend. and in May, the Pratt & Whitney F100 engine, the power plant for the F-15 Eagle and F-16 Fighting Falcon was tested with synfuel. Most recently in August, the F-22 Raptor performed aerial refueling using synthetic fuel.

By early 2011, all air force aircraft are scheduled to be tested and certified to fly on synfuels, and by 2016 the air force hopes to fuel half of its cross-continental flights with domestic synfuel blends. This equates to some 325 million gallons, or 12.5 percent of the total annual 2.6 billion gallons consumed by the U.S. Air Force.

There are multiple problems with this plan. One is that synfuel derived from domestic natural gas does not assure the air force a dependable supply, since U.S. natural gas reserves are insufficient to meet its or the country’s needs. While the production of synfuel from coal, oil shale, and biomass may solve this particular constraint, considerable technical, environmental, and economic issues remain. The only two viable alternatives to conventional oil that could come from domestic resources are oil shale and coal, which is prohibitively expensive for the former and faces extremely difficult technical challenges for the later. This is why the air force is working with the civilian aviation industry to expand demand for synthetic jet fuel, in an effort to make it more attractive to produce on the part of private industry and thus lower the cost.

Even as synfuels could free the Pentagon from its reliance on foreign sources of oil, they are worse for the environment. The Pentagon proclaims that synfuels burn cleaner, emit no sulfur dioxide, and pollute much less than conventional jet fuel, yet the full conversion process from coal to liquid through the FT process creates 1.8 times more carbon than simply refining petroleum. So the claim that synfuel will reduce the Pentagon’s carbon emissions is simply wrong. Only the U.S. Navy has a rather sound energy vision when it comes to emissions. The National Defense Authorization Act for 2008 directed that future Navy aircraft carriers, submarines, and cruisers should be nuclear powered. The Navy’s next-generation cruiser, the nuclear-powered CG(X), which will replace the Ticonderoga class AEGIS cruiser, is expected to be produced by 2011.


The piecemeal energy approach the U.S. military is taking will not be sufficient to wean itself off oil. What the Pentagon must do, if it is serious about changing its energy usage, is create a comprehensive energy consumption profile and formulate a long-term energy policy.

A grand and viable long-term energy strategy for the U.S. military is necessary due to the length of time it will take to institute future changes, develop alternative energy sources, and cycle old equipment (fuel-intensive equipment and vehicles ordered without an energy plan) out of the services. Making long-term plans now will ensure that military planners can consider energy efficiency in equipment purchasing.

Furthermore, an energy profile would answer the basic questions that would allow intelligent choices to be made so that policy changes could do the most good. Part of creating such a profile would involve data collection reform that has skewed the military’s picture of its own fuel consumption. Official oil consumption figures from the U.S. military are underreported, due to accounting flaws: Certain vehicles rented or leased are not included in fuel consumption statistics; fuel consumption by private contractors, which has grown more and more important to the U.S. war effort, is not included; and fuel costs accrued by private transportation companies that ferry U.S. military personnel are also absent. A bigger issue is that in the two Gulf Wars, fuel was obtained at no cost and was not included in Pentagon statistics. During the First Gulf War, Saudi Arabia and the United Arab Emirates supplied 1.5 billion gallons of fuel for no charge, and in 2003 Kuwait supplied U.S. military forces with free fuel as well. None of this was included in the Pentagon’s fuel consumption statistics.

Other improvements must also include strong demand-side conservation including a more energy-efficient infrastructure. Only a combined effort including all these suggestions will offer possibilities for reducing the U.S. military’s dependence on traditional energy sources and the associated logistics required to support them.

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