Martin Tobias stepped down as chief executive and chairman of Imperium Renewables, the Seattle-based biodiesel maker said late Friday in...

Share story

Martin Tobias stepped down as chief executive and chairman of Imperium Renewables, the Seattle-based biodiesel maker said late Friday in a terse statement that gave no explanation.

Imperium, which operates the nation’s largest biodiesel plant, said founder John Plaza was named interim CEO and current director Nancy Floyd was named chairman. Tobias will not remain at the board. The company filed plans in May for a $345 million initial public offering but has not completed the stock sale.

Company officials were unavailable for comment. Floyd is managing director of Nth Power, a San Francisco-based venture capital firm that focuses on alternative energy and owns a 9 percent stake in Imperium.

Tobias, a former Microsoft manager and tech entrepreneur, joined Imperium in May 2005 and owns 7.9 percent of its stock, according to regulatory filings.

Under Tobias, the company raised $113 million during the first quarter, in one of the largest alternative energy venture investments ever. Imperium also obtained a $100 million loan from major banks in June and inaugurated its 100 million gallon-a-year biodiesel plant in Grays Harbor.

The company has laid out ambitious plans to build additional large biodiesel facilities in Hawaii, the U.S. East Coast and Argentina.

The Grays Harbor plant is operating at full capacity, Imperium said Friday in its statement. The company also said it has turned its original Seattle Biodiesel plant into a research center for next-generation feedstocks to produce biofuels.

In 2006, Tobias’ compensation amounted to about $227,000, including a bonus. His base salary of $150,000 was to be doubled after the IPO.

Plaza founded Imperium predecessor Seattle Biodiesel in 2004, and has acted as president of the company since then. He’s a former airline pilot and owns nearly a quarter of Imperium’s shares.

Jabe Blumenthal, a Seattle-based investor in Imperium, said he was surprised at news of the management change, but was “pretty neutral” about it.

Propel Biofuels founder Rob Elam lamented Tobias’ departure. “Martin has been a great supporter of Propel and of clean tech in Seattle,” said Elam, whose company distributes biodiesel manufactured by Imperium. “We hope he remains involved in the business.”

Ángel González: 206-515-5644 or agonzalez@seattletimes.com