press release

From Grills to the Grid: City Of Millbrae and Chevron Energy Solutions Create a Novel Way to Generate Electricity

Innovative upgrades will use kitchen grease to help power wastewater treatment facility, reduce air emissions, increase city's revenues and lower city's energy costs

JOINT NEWS RELEASE: Issued by Chevron Corporation and the City of Millbrae, Calif.

MILLBRAE, Calif., Sep. 21, 2005 -- The City of Millbrae, Calif., and Chevron Energy Solutions (Chevron ES), a unit of Chevron (NYSE: CVX), today announced they are starting construction of facilities at Millbrae's Water Pollution Control Plant (WPCP) that will generate on-site electricity from restaurant kitchen grease and other organic matter. The upgrades to the WPCP will make it one of the first wastewater treatment plants in the U.S. to receive and process inedible grease in a comprehensive system specifically designed to control odors, generate reliable power, reduce energy costs and provide a new municipal revenue stream.

The new system will efficiently create and use a free biofuel – digester gas produced from grease – and will increase the amount of "green power" now generated by the facility's cogeneration plant by 40 percent. Because the system will generate electricity on-site, the city will avoid having to purchase about 1.5 million kilowatt-hours from the local utility each year. This lower demand translates to 1,178,000 fewer pounds of carbon dioxide emissions annually, equivalent to planting 166 acres of trees.

The upgraded system – the latest Chevron ES project to develop an alternative energy source – will produce about $264,000 in combined energy savings and revenues from its grease receiving facility each year. This will effectively pay for the $5.5 million facility improvements – as well as maintenance – at no new cost to the city's ratepayers. The project may be awarded a rebate through PG&E's Self-Generation Incentive Program, which would reduce the total project cost by about $200,000.

The innovative new system is a culmination of nine months of collaborative planning by the City of Millbrae and Chevron ES, which is engineering and managing the installation as prime contractor. Designed as a cost-effective way to renovate the City's aging wastewater treatment infrastructure, the system's equipment is enclosed to minimize odors and will include:

  • A new 250-kilowatt microturbine cogeneration system, fueled by natural and digester gas, to power the WPCP's wastewater treatment facilities.
  • A compressed natural gas tank to store fuel on site.
  • An innovative facility that will receive inedible kitchen grease – produced mostly by local restaurants and collected by hauling companies – providing a revenue stream for the City and a source of methane for on-site power generation. The facility will be easily accessible, operate 24 hours a day, and provide deodorizing washes for grease hauling trucks.
  • "Chopper pumps" that reduce grease particle size and help process and move the grease to two anaerobic "digester tanks." The tanks house microbes that digest organic matter from wastewater and produce methane (natural gas) as a byproduct, which is used to fuel the microturbine.

Excess heat produced by the microturbine will warm the digester tanks to their optimum temperature. This beneficial use of otherwise wasted energy while generating electricity is known as "cogeneration."

"Life is energy, and when you waste energy, you waste life," said Dick York, WPCP superintendent. "Our new facility upgrades at the Millbrae WPCP provide a novel solution to reduce the burden on landfills, support our own energy needs and simultaneously recoup costs. CES has been a valuable partner, working with us to pioneer a project that could shape the future of wastewater treatment plants around the country."

"The City of Millbrae approached us with a very complex situation, with the goal of upgrading its facilities with more effective technologies while keeping costs under control," said Jim Davis, president of Chevron Energy Solutions. "We love these types of challenges, because they allow us to explore innovative solutions for energy production. In this case, the grease-receiving facility was the key to making this project feasible – not only will it reduce the WPCP's energy expenses, but it will also open a new revenue stream to help offset the cost of new equipment."

Chevron Energy Solutions partners with institutions and businesses to improve facilities, increase efficiency, reduce energy consumption and costs, and ensure reliable, high quality power for critical operations. Its projects are funded by the energy savings they generate, which saves taxpayer dollars, and reduce air emissions, extend fuel supplies, and enhance indoor environments. For more information, please visit the company's web site at

Updated: September 2005