San Francisco receives grease grant

Web exclusive posted June 9, 2008 at 5:02 p.m. CST

The city of San Francisco is taking yet another step towards becoming energy self-sufficient as it continues to find creative uses for "end-of-life" grease.

The city is already well into its first year of a city-wide grease recycling program which turns used fryer oil, or yellow grease, into usable fuel. Now, the city plans to convert the less desirable brown grease into fuel as well. San Francisco Mayor Gavin Newsom announced May 29 the city has been awarded a $1 million grant from the California Energy Commission to build its first brown grease biodiesel facility. The pilot plant will be colocated with the city's sewage treatment plant. Construction is expected to begin soon and should be completed by the end of the year.

Brown grease is best described as the dark gunk left over in grill traps and kitchen sink grease interceptors. It poses a problem for producers who want to use it for a feedstock because it has a very high free fatty acid content. Typically, only the yellow grease is used for biodiesel purposes. Brown grease is simply discarded.

San Francisco officials estimate there are 2.5 million gallons of brown grease, 1 million more gallons than yellow grease, in the city that could potentially serve as feedstock for the facility. They plan to produce three types of biodiesel at the brown grease facility: ASTM-certified biodiesel; lower grade fuel for running sewage treatment plant turbines and pumps; and energy to fuel cogeneration in order to capture methane gas to convert it to electricity.

"Our program to turn waste cooking oil and yellow grease into biodiesel has been an enormous success, but San Francisco must continue to raise the bar when it comes to reducing our greenhouse gas emissions and exploring alternative energies," Newsom said. "With this grant, our unique brown grease-to-biodiesel plant will break new ground for sustainable fuel production in California and serve as a model for the entire state."

The San Francisco Public Utilities Commission runs the yellow grease collection program and will lead the brown grease project. Karri Ving, SFPUC's wastewater division biofuels coordinator, told Biodiesel Magazine that the brown grease project's goal is to run an ASTM certified biodiesel production facility for four years. "The state's asked us to develop a demo plant to show that it's possible for any sewage treatment plant to, with minimal upgrade, turn into an energy recovery facility. We're very excited about this plant," Ving said.

The SFPUC and its engineering partners will match the state's $1 million grant with an additional $1.7 million to cover equipment, labor and other expenses.

San Francisco's grease recycling program was featured in the May issue of Biodiesel Magazine. For more information, visit: http://www.biodieselmagazine.com/article.jsp?article_id=2293&q=san%20francisco&page=2.