More than one-third of the Senate is calling for removal of provisions in the defense authorization bill that would limit military efforts to develop alternative fuels.

In a Nov. 16 letter to Senate leaders, 38 senators backed Pentagon biofuels programs as worthy investments, given that the U.S. military is the largest user of oil in the world.

“Alternative fuels will not supplant fossil fuels entirely; however, replacing even a fraction of the fuels consumed by DOD with domestic alternative fuels has the potential to advance U.S. national security, improve strategic flexibility and insulate the defense budget against spikes in the cost of fossil fuels,” Sens. Susan Collins, R-Maine, Mark Udall, D-Colo., and 36 additional Democrats wrote in the letter released Nov. 19.

The letter singles out two provisions included in the defense authorization bill (S 3254) that would limit funds for procuring alternative fuels if the costs exceed those of traditional fossil fuels and bar the department from entering into contracts to support construction of biofuels refineries.

Opponents of the Defense Department’s biofuels programs, including Republicans John McCain of Arizona and James M. Inhofe of Oklahoma, added the provisions to the bill during an Armed Services Committee markup in May. The House-passed companion bill (HR 4310) includes similar restrictions.

Senate Armed Services Chairman Carl Levin, D-Mich., and McCain, the panel’s ranking member, have been pressing for floor time for the Senate bill. But committee member Joseph I. Lieberman, I-Conn., said last week that the amendment process remains in flux.