The federal government is soliciting proposals for how it might use biofuels to replace traditional diesel in Royal Canadian Navy vessels — assuming the price is right.

"Naval vessels and platforms have traditionally operated by the use of fossil fuels to power many of their systems. Biofuels are environmentally much cleaner than fossil fuels, producing less air pollution and consuming some materials that would otherwise be considered garbage," says a notice posted Monday.

"Simply converting fossil fuel powered systems to biofuel-powered systems can be complicated and may become costly from the perspectives of financial, space and maintenance requirements, for example.

"In order to determine if the costs incurred can be justified, the benefits or efficiencies gained must also be determined."

U.S. Navy green initiative

Those efficiencies include kilometres and dollars per litre, the amount of time and people needed to maintain the system, space and storage requirements, and whether biofuels reduce emissions and generate much waste.

A similarly worded notice was posted in late 2011, but it's not clear if a previous biofuels report was ever commissioned. A spokesman for the Royal Canadian Navy did not immediately return calls Monday.

The biofuels idea is not uniquely Canadian. In 2009, the U.S. Navy announced its Great Green Fleet initiative, which aims to fuel an entire aircraft carrier strike group with alternative sources of energy — including nuclear power — by 2016.

Energy-security concerns — the U.S. Department of Defence is among the world's largest users of oil, much of it foreign — prompted the Great Green Fleet initiative.

The U.S. Navy deployed ships and aircraft running on a 50-50 mix of old-school fuel and biofuels made from used cooking oil and algae off the coast of Hawaii last year as part of a major naval exercise.

Higher cost of biofuels

Politics may still scupper the navy's green dreams.

The Great Green Fleet plan faces staunch opposition in the U.S. Congress from Republicans, who say they can't justify the higher cost of biofuels at a time when defence budgets face the prospect of deep cuts.

Whether the biofuels initiative would face such backlash in Parliament is another question. The ethanol and biofuels industries have received millions of dollars in funding from the Conservative government over the years.

And at least one other government agency is eyeing alternative energy sources for its vehicles.

The U.S. coast guard recently issued a tender for low-emission ships that would incorporate hydrogen fuel cell technology.

The three offshore fisheries science vessels are intended to replace four aging coast guard ships and would be stationed on the Atlantic and Pacific coasts. They are part of the fleet under Ottawa's $33-billion national shipbuilding procurement announced last year.