Minnesota temporarily lifts B5 mandate for No. 1 fuel

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The Minnesota Department of Commerce issued a waiver on the state's B5 mandate for No. 1 diesel fuel only, effective Jan. 15 to March 31, citing very rare instances of storage tank filter clogging.

No. 1 diesel has a much lower cloud point than No. 2, which is why winter blends in Minnesota rely on No. 1 as a blend agent or primary fuel during the coldest months of the year, but no one has a definitive explanation yet as to why No. 1 B5 is displaying issues while No. 2 B5 is not.

Hoon Ge, a fuel consultant with MEG Corp, told Biodiesel Magazine that No. 1 B5 should perform down to minus 30 degrees Fahrenheit, but he saw issues with samples of No. 1 B5 at minus 10 degrees. Even red dye No. 2 B5 with cold flow additives was performing at that temperature. "If you would have told me a month ago that No. 1 and 5 percent biodiesel would be having issues at minus 10 degrees, I would not have believed it," Ge said.

"The incidents of reports were very spotty," said Ralph Groschen, senior marketing analyst for the Minnesota Department of Agriculture. "There were so few complaints coming from far-flung areas-in Marshall, then Mankato, Grand Forks (N.D.), and then down in Alexandria-but most terminals had no problems. Those that did mostly involved above-ground storage tanks."

Out of about 12 filters the state collected and tested, none point to biodiesel as the problem. "We don't have a smoking gun in this case because so far all the fuel met specification," Groschen told Biodiesel Magazine. He noted, however, that more accountability needs to be built into the state's sampling protocol. "We came up with a list of elements we want to see included in company fuel samples, including where the last two deliveries came from and when they were delivered," he said.

While answers are being sought, hypotheses are circulating. Concerns have arisen over the past few years regarding desulfurization processes used by refineries to produce ultra-low sulfur diesel, which reduces aromatics in the fuel and alters the paraffinic structures, affecting cold flow. The aromatic and paraffinic structures of No. 2 ULSD may not be affected to the point they are in No. 1 ULSD, which could explain why No. 1 is having issues with 5 percent biodiesel but No. 2 is not.

Last year in Bloomington, Minn., school bus filters were clogging and immediately biodiesel was blamed, even though later the investigation concluded that petroleum components, not biodiesel, caused the trouble. Another possibility is that, since the IRS extended the deadline for passing the cold soak filtration test (CSFT) until Oct. 1, 2009, perhaps B100 that did not pass the CSFT was in the distribution chain and precipitated these rare events of storage tank clogging in Minnesota. Groschen said, "Hopefully, this will not be a factor next year."

Groschen added that the B5 waiver for No. 1 fuel is not a requirement that prohibits blending biodiesel into No. 1, but rather it's a waiver that allows the sale of it without biodiesel.