Putting Waste to Work: Chevron and the City of Millbrae Turn Kitchen Grease Into Biogas to Power Wastewater Treatment Plant
Innovative system generates electricity from restaurant grease to meet 80 percent of plant's power needs while also reducing costs and curbing greenhouse gas emissions
MILLBRAE, Calif., Nov. 16, 2006 -- Chevron Energy Solutions, a unit of Chevron Corporation (NYSE: CVX), and the City of Millbrae today celebrated the completion of new facilities at Millbrae's Water Pollution Control Plant that use a common urban waste – inedible kitchen grease from restaurants – to naturally produce biogas for generating renewable power and heat to treat the city's wastewater.
The unique system, engineered and installed by Chevron Energy Solutions, includes a grease receiving station and an expanded cogenerator as well as other upgrades that result in annual revenues and energy savings of $366,000 for Millbrae while nearly doubling the amount of "green power" produced at the plant.
More than 3,000 gallons of restaurant grease – the kind washed from grills and pans – will be delivered to the plant each day by grease hauling companies, which pay a city fee for disposals. Microorganisms in the plant's digester tanks eat the grease and other organic matter, naturally producing methane gas to fuel the plant's new 250-kilowatt microturbine cogenerator to produce electricity for wastewater treatment. Meanwhile, excess heat produced by the cogenerator warms the digester tanks to their optimum temperature for methane production.
"This project clearly demonstrates that cities can develop renewable energy economically, with multiple benefits to urban communities," said Jim Davis, president of Chevron Energy Solutions. "By applying proven technologies and looking at the entire waste stream in new ways, the City of Millbrae has cost effectively upgraded its facilities, reduced its operating costs, created new revenue and solved environmental challenges all at the same time."
"This innovative project brings new meaning to the term 'sustainable development,'" said Millbrae Mayor Robert Gottschalk. "Through our partnership with Chevron Energy Solutions, we're taking an urban waste and turning it into an asset for the city and the environment."
Nationally, restaurants produce an average of 14 pounds of inedible grease per capita annually – a total of nearly 4.2 billion pounds each year in the United States alone. Much of this grease is disposed of in landfills, where it releases methane – a potent greenhouse gas – as it decomposes, sometimes directly to the atmosphere. Millbrae's grease receiving station will reduce the amount of grease sent to landfills.
The grease and other organic matter will produce enough biogas at the plant to generate about 1.7 million kilowatt hours annually, which will meet 80 percent of the plant's power needs and reduce its electricity purchases significantly. This lower demand for utility-generated power reduces carbon dioxide emissions by 1.2 million pounds annually, the same amount of carbon dioxide absorbed by planting about 170 acres of trees.
The total cost of the project, $5.5 million, was reduced by about $200,000 with a rebate awarded through the state of California's Self-Generation Incentive Program administered by Pacific Gas and Electric Company. The net amount, along with maintenance costs, is being funded entirely by savings from the new system and, therefore, will have no effect on the city's wastewater treatment rates.
The project's completion is being celebrated today at an event in Millbrae attended by national, state and local government officials and representatives from business, environmental organizations and academia.
"This is the only wastewater treatment plant in the U.S. to receive and process inedible grease in a self-funding, purpose-built system that successfully addresses so many challenges simultaneously," said Dick York, superintendent of the Millbrae plant. "It's a complete solution that could be adopted in many cities around the country."
Chevron Energy Solutions partners with institutions and businesses to improve facilities; increase efficiency; reduce energy consumption and costs; and ensure reliable, high-quality energy for critical operations. The company employs proven technologies to meet customers' specific needs, including infrastructure technologies, energy controls, solar photovoltaics, fuel cells, biomass and other systems. For more information about Chevron Energy Solutions, please visit www.chevronenergy.com.
Chevron Corporation is investing across the energy spectrum to develop energy sources for future generations by expanding the capabilities of today's alternative and renewable energy technologies. Since 2000, Chevron Corporation, through its various subsidiaries, has spent more than $1.5 billion on renewable energy projects and on delivering energy efficiency solutions. Focus areas include geothermal, hydrogen, biofuels and advanced batteries as well as wind and solar technologies. Chevron is the largest renewable energy producer among global oil and gas companies, producing 1,152 megawatts of renewable energy primarily from geothermal operations. More information about Chevron is available at www.chevron.com.
Published: November 2006