The Miramar landfill site in San Diego, one of the biggest in the United States, handles over 50 million tons of waste and is electrically self-sufficient. The facility powers two cogeneration plants, for a total of 15 MW of generated electricity. The Metro Biosolids Center in San Diego, instead, is a state-of-the-art biosolids treatment facility which collects on average 118 million gallons of waste water a day and 110 tons of sludge from two cogeneration plants. 6.4 megawatts of energy is generated, which is mainly sold to the mains network.