Management shake-up heats up rising biodiesel star

Another day, another CEO ouster at a green tech start-up.

Martin Tobias is out as chairman and CEO of Imperium Renewables, the company has announced. John Plaza, who founded the company with Tobias, is interim CEO while Nancy Floyd has taken over as chairman.

Tobias has been the spokesman and public figure for Imperium since its founding. The company has raised more than $200 million dollars and earlier this year christened a 100-million gallon refinery in Washington state. It has plans to build similar sized facilities in Hawaii, Argentina and elsewhere.

The ouster of Tobias is something of a surprise. He was a frequent fixture on the green-tech conference circuit and presided over the unveiling of the Washington facility in August. The company sent out a press release on the departure of Tobias at 4:30 p.m. PST on the Friday before the Christmas break. Talk about getting maximum exposure for your news.

Biodiesel, however, is a tough business. The fuel, made from vegetable or meat oils, actually costs more than regular diesel. The federal government gives refiners a $1 to 50 cent per gallon subsidy. Imperium had filed preliminary papers for an IPO, but recent rumors make it sound like the company had to postpone the proposed date for the IPO. No confirmation on that.

Several green tech companies, including Miasole and Greenfuel Technologies, have had to swap founders recently. In many cases, investors have plunked in a veteran from a tech company to oversee growth. It's an ongoing debate: some investors say they best executives for these companies come from the fuel and energy business. Others lean toward people who come from the Internet and tech world because they know how to take companies public.

Tobias was actually both. He was a VC in the software world and founded a few companies before starting Imperium. (CNET News.com also republishes entries from his blog.)

Biodiesel emits 78.45 percent less carbon dioxide from well (or farm field) to wheel than regular diesel, according to a report from the Department of Energy.

"About 11 percent of the weight of B100 is oxygen. The presence of oxygen in biodiesel improves combustion and therefore reduces hydrocarbon, carbon monoxide and particulate emissions," the report states.

The presence of oxygen, however, also increases nitrogen oxide emissions and reduces mileage. Researchers are trying to find additives or processes to ameliorate these side effects.