IF THE US military were a country, it would be the 35th biggest consumer of oil in the world: its daily demand for nearly 45 million litres of crude is larger than Sweden’s national consumption.
For the Pentagon, these figures are a matter of life and death. Truck supply convoys are highly vulnerable to attack: delivering fuel and water in Afghanistan and Iraq. In the longer term, military officials worry about keeping the world’s dominant fighting machine rolling when the oil runs out.
“Energy is our soft underbelly,” said of the US Marine Corps’ Expeditionary Energy Office in Washington DC, speaking in September at a demonstration of fuel-saving technology.
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This is why the Department of Defense has set a goal of supplying 25 per cent of the military’s energy from renewable sources by 2025 (see “The Pentagon’s green offensive”). The navy is even more ambitious, planning for 50 per cent renewables by 2020. While saving the environment isn’t the Pentagon’s main goal, military investments could foster innovations in clean energy that would ripple through civilian society. There are precedents: both the internet and the GPS technology used by your smartphone began life as US military projects.
The Pentagon’s spending plans must be approved by the US Congress, however, and the navy’s targets for biofuels are a huge bone of contention. While lawmakers from oil and gas-producing states are leading the opposition, even advocates for green energy worry that it’s too early to know which biofuel technologies – if any – will deliver real environmental benefits when produced on a commercial scale.
Some aspects of the military’s clean energy push are uncontroversial. Given attacks on supply convoys, it’s clearly a good idea to cut fuel consumption at bases in the theatre of war. Since 2010, fuel-saving technologies have been showcased twice yearly at (ExFOBs), where military personnel put the latest clean-tech gizmos through their paces.
The latest event, held in September at the , was part trade show, part proving ground. Vendors of air-conditioning units, solar panels and insulation systems hawked their wares as marines took notes, musing whether the equipment could cope with Afghanistan’s scorching temperatures and howling dust storms.
Away from reporters’ prying eyes, the marines really got down to business, driving Humvees over solar panels to test their durability.
The main focus of the September event was keeping troops and equipment cool, which accounts for . Among the products on display were vests for soldiers with tiny tubes of water running through them, and air-conditioned boxes for electronics – the idea being to save energy by cooling only people and electronics rather than entire tents.
Equipment tested at previous events is already in use. The first ExFOB in 2010 debuted a portable, 300-watt solar-panel system known as GREENS (pictured on page 8) and a small flexible panel that attaches to a soldier’s backpack and can power personal electronic gear. Two years later, more than 100 GREENS panels are being used overseas, and more than 600 troops carry solar-powered backpacks.
Power plants
Domestic military bases are also switching to solar. In late October, two utility-scale solar plants went online at naval bases in California, and a third will open at a marine base in the state next year.
As the war in Afghanistan winds down, the US military is expected to shift its main overseas focus to potential flashpoints in the Pacific – where powering coastal and island bases will be crucial.
In addition to investing in wave power, the Pentagon has commissioned research into ocean thermal energy conversion systems. These use warm surface water to turn a liquid with a low boiling point, such as ammonia, into a vapour that drives a turbine. The vapour is then recondensed using colder water drawn from deeper ocean layers.
Military investment may be crucial to create a market for such experimental energy technologies. The Pentagon’s financial muscle has already provided a boost for companies that supply microgrids – self-contained energy generation and distribution systems that can operate independently of the main power grid. In 2011, by market research firm SBI Energy, based in Rockville, Maryland, concluded that military investments were crucial to kick-starting the growth of a microgrid industry with $4 billion in annual global revenues.
“Military money may be crucial to create a market for new energy technologies”
“We really have a mutual interest in this,” says , the navy’s deputy assistant secretary for energy, embracing the idea that the military can partner with the civilian sector. “We can play the role we’ve played over many decades, which is to be that catalyst.”
It is in building a market for biofuels that the military could play its most important catalytic role. Liquid fuels for warships, aircraft and other fighting vehicles account for about . And its investments in biofuels are already proving crucial to an embryonic industry that is struggling to find its feet.
“If they weren’t there, we’d be in real trouble,” admits Timothy Zenk of in San Diego, California, which is producing biofuels from algae.
The navy is leading the way. By 2020, it expects to buy 1.27 billion litres of alternative liquid fuels per year. To prove its seriousness, the navy bought 1.7 million litres of biofuel this year at almost $7 per litre – the biggest such purchase in history – for a single demonstration project.
Algae power
In July, the , a strike group comprising an aircraft carrier, a cruiser, two destroyers and a fuel tanker, sailed around the Hawaiian islands. The carrier, the USS Nimitz, was nuclear powered. But everything else, including the Nimitz’s strike aircraft, ran on a 50:50 mix of petroleum and biofuel derived from cooking oil and algae.
The with jets running on biofuel made by yeast genetically engineered by of Englewood, Colorado, to produce energy-rich isobutanol, instead of ethanol. That cost more than $15 per litre, but if prices drop sufficiently, the – enough to power half of its aircraft.
These plans have provoked push-back from the US Congress. A pair of proposed amendments to the Department of Defense’s 2013 budget would from purchasing any fuel more expensive than conventional fossil fuels.
“[Defense] Secretary [Leon] Panetta has a real war to win, and he should not be wasting time perpetrating President Obama’s global warming fantasies,” , a Republican Senator from Oklahoma who introduced one of the amendments in May.
Opponents argue that the US government has a poor record in picking winners in clean energy, noting the collapse of the Californian solar energy firm Solyndra, which after receiving $500 million in loan guarantees from the US Department of Energy.
That criticism is hard to counter for biofuels, given the uncertainties that surround the competing technologies. Arguments rage over whether biofuels grown from crops will cut overall greenhouse gas emissions, and whether there’s even enough agricultural land to support their production.
Fuels made from algae seem the best bet, says , an environmental engineer at the University of Virginia in Charlottesville. Sapphire Energy has built the first commercial-scale farm in New Mexico, where algae grow in huge tanks of brackish water. At the company’s San Diego headquarters, the farm is replicated on a small scale in a greenhouse. When Â鶹´«Ă˝ visited the facility in September, paddlewheels churned a scummy teal-coloured liquid around a bath-sized tub. When a company scientist opened a bucket of the final product, extracted from the algae by heat and chemical conversion, it looked and smelled like crude oil.
But algal biofuels have their own problems. Last week, a concluded that large-scale production is unrealistic, at least with current technology, as it requires unsustainable amounts of water and nitrogen. What’s more, carbon dioxide to feed the algae comes from burning fossil fuels – potentially game-changing technology to pull CO2 from the air has yet to prove its worth.
The military is well aware of the criticisms, says Hicks. That’s why the navy is investing in a range of alternative fuels, including waste biomass from industrial processes and oil from Camelina, a relative of mustard. “At the end of the day, we want options,” Hicks says.
Current high prices will also drop with the military’s financial backing, Hicks argues. A predicted that with major investment, some biofuels could compete with conventional jet fuel by 2018.
Political wrangling over the Pentagon’s push into biofuels will begin again in earnest after next week’s elections. Military officials hope to convince hawks in Congress that the investment is needed to ensure the military’s war-fighting ability.
“We’re not doing it to be faddish; we’re not doing it to be green,” at the Great Green Fleet demonstration. “We’re not doing it for any other reason except it takes care of a military vulnerability.”
Carbon Lock-down
The US military is not only investing in clean energy, but also experimenting with methods to reinforce the ability of natural carbon sinks, such as vegetation, to pull carbon dioxide from the air.
Military bases in the deserts of the south-west US are on the cutting edge of carbon sequestration. In California’s Mojave desert, vegetation and the lichens and bacteria that make up the soil crust may extract as much carbon from the atmosphere as a temperate forest of the same area, according to one study ().
of the Desert Research Institute in Reno, Nevada, is now quantifying carbon sequestration at the in southern California. His group has set up towers with equipment to measure atmospheric fluctuations in CO2, and taken aerial photos of the vegetation from low-flying helicopters. The data will allow the researchers to identify which areas of the base are the greatest carbon sinks and may suggest ways to manage the desert to sequester more carbon.
In future, this could help the base meet greenhouse gas emission targets under . It is already possible to offset emissions cuts by planting trees, but new rules would be needed to allow similar credits for boosting desert carbon sinks.
