ST. PAUL, Minn. — Minnesota now requires that diesel fuel contain a 5-percent blend (B5) of homegrown biodiesel. The biodiesel content mandate increased from B2 on Friday.

The increase is part of Gov. Tim Pawlenty’s effort to reduce the state’s dependence on foreign oil. In 2007, Pawlenty unveiled a plan to take the state’s biodiesel requirement from B2 to B20 by 2015.

"Minnesota has led the nation in unleashing a renewable energy revolution," Pawlenty said. "Other states are starting to catch on, and it’s time for us to continue to blaze the trail to a cleaner, more secure energy future. Increasing the level of biodiesel in diesel fuel means that more of our energy will come from farm fields rather than oil fields, and that's a good thing."

In the program's next phase, B10 will be required beginning May 1, 2012.

“Increasing biodiesel in our diesel fuel allows us to take advantage of a renewable fuel made in Minnesota, which in addition to being environmentally responsible, also adds to our state's bottom line,” said Ed Hegland, a soybean farmer and chairman of the National Biodiesel Board (NBB).

Biodiesel has been shown to reduce greenhouse gases and other emissions, and it is nontoxic and biodegradable. Pure biodiesel contains no petroleum, but it can be blended at any level with petroleum diesel. Blends can be used in most diesel engines with few or no modifications.

Biodiesel can gel in cold weather, but the NBB said in a statement that early concerns with the B2 requirement were overcome through "enhanced quality control."

NBB officials went on to say that “it is safe to use up to a 20-percent blend of biodiesel year-round, in even the coldest of climates. Biodiesel will gel in cold weather, just like regular diesel fuel. But biodiesel blends can be treated for winter use in similar ways that No. 2 diesel is treated. Cold weather concerns are greatly diminished with lower blends like B5.”

However, the Minnesota School Bus Operators Association (MSBOA) reported in a recent newsletter that its members and other transportation operations experienced a number of fuel filter gelling situations while using B2 during the winter. MSBOA has been keeping a record of the problems and sharing concerns with the Minnesota Truckers Association.

Washington, Oregon, Pennsylvania, Louisiana, New Mexico and Massachusetts have also passed biodiesel requirements.