A member of the Petroleum Oils and Lubricants squadron at the 379th Air Expeditionary Wing, supplies fuel to a KC-10 aircraft on December 30, 2002 in Al Udeid, Qatar. Two hearings in the House this week will question whether the Pentagon's efforts to go green and use alternative fuels are worth the cost. - 

Jeremy Hobson: Well not far from the Supreme court today, a couple of congressional panels will look at the Military's push into alternative energy. The armed services have set aggressive goals to lower fossil fuel use.

But now, there's some pushback, as Scott Tong of the Marketplace sustainability desk reports.

Scott Tong: Everybody’s tightening their belts in Washington, including the Pentagon. So can it afford $400 a gallon for alternative jet fuel?

That’s how Republican senator John McCain framed it last week. The military puts it differently, says Rob Melnick at Arizona State University, which does sustainability training for the army. Take Afghanistan: fuel supply lines are long and vulnerable. So why not try solar?

Rob Melnick: If you can bring power to the frontlines at the source, not from thousands of miles away, that’s a considerable savings of both life and money.

Investing in new fuels is like cell phones -- early prototypes are pricey, but get cheap -- if the technology can scale.

Melnick: For every invention that someone puts some money into for a cell phone, there are thousands of Chapter 7s and 11s.

Melnick thinks newer technologies, like replacement fuels, are pricey and more politically vulnerable. More competitive energies like solar, he thinks, are less so.

In Washington, I’m Scott Tong for Marketplace.

Follow Scott Tong at @tongscott