Environmentalists in Montana opposed the plant because of concerns about greenhouse gas emissions and other pollution. They also were worried about its effect on the Missouri River, since the production process would require millions of gallons of water daily. Additionally, depending on the properties of the coal being used, it can take as much as a ton to produce a single barrel of fuel, exacerbating the environmental impact from coal mining.
Federal law bars agencies from purchasing synthetic fuel unless the lifecycle greenhouse gas emissions are equal to or less than those of petroleum, but there are no standards for measuring lifecycle emissions for either fuel. Nonetheless, Air Force officials have said they won't buy synthetic fuel unless the production process is shown to be greener than that for conventional fuel.
The Air Force didn't mention environmental concerns in a statement about the decision at Malmstrom. The service cited the degradation of security in a weapons storage area, interference with missile transportation operations and safety issues. But Air Force spokesman Gary Strasburg said environmental issues were a factor as well.
"There was a location issue, which included environmental concerns," Strasburg said. "We're willing to consider other proposals elsewhere."
Turning coal into liquid fuel isn't new. The Germans pioneered the process in the 1920s and used it in World War II; the South Africans used it during apartheid rule when trade embargoes limited the nation's access to petroleum.
Air Force leaders see having a reliable domestic source of synthetic petroleum as critical. The service burns about 2.6 billion gallons of petroleum-based fuel annually and it wants to begin using a 50-50 blend of synthetic and conventional aviation fuel by 2016, which would significantly reduce its dependence on petroleum.
The Air Force is on track to certify its entire fleet of aircraft for using the 50-50 blend by 2011.