The City of San Diego, California, a 2003 Green Power Leadership Award winner, is pursuing energy independence and becoming a model city by using renewable energy resources and energy conservation. The City of San Diego generates more than 167 GWh of renewable power on an annual basis but only maintains REC ownership on 49 GWh because of incentive and tax policies that existed when the projects were developed. The City owns and operates a gas utilization facility located in the Point Loma Waste Water Treatment Plant (PLWWTP). This cogeneration facility is powered by wastewater methane gas and generates 4.53 MW of electricity. In addition, PLWWTP owns and employs a hydroelectric facility producing another 1.35 MW of power generated by the 100-foot drop of treated sewage flow exiting the plant into the ocean. Landfill methane gas produced by the set of digesters at the Metro Biosolids Center (MBC) from the City operated Miramar Landfill is captured and converted to produce 6.4 MW of electricity by an external vendor. Following the success of the MBC, the North City Water Reclamation Plant was built to produce 3.8 MW of energy from excess landfill gas. A third party partner produces power for the wastewater treatment operations and also sells excess electricity to the local utility. A total of 10.2 MW is produced from cogeneration as a result of these two facilities. Approximately half of the 10.2 MW produced at the wastewater treatment plants is utilized on site. The City has more than 20 photovoltaic systems installed throughout the region on City-owned facilities. These systems produced over 3.9 GWh of solar energy in 2017. The power produced is consumed on site or net metered to the local utility through a mix of power purchasing agreements and City ownership financing mechanism.
