Cleaning used water is an energy-intensive process.
To manage our operating costs and reduce the environmental impact of our energy use, we have an active energy efficiency program. We also generate much of our own energy from renewable sources. Thanks to our partnerships with the Energy Trust of Oregon and Oregon Department of Energy, we produce enough energy to power the equivalent of 400 homes per year.
Clean Water Services generates more than 21 million kilowatt-hours of electricity annually, which meets about 45% of facility electricity needs and offsets about 70% of the natural gas needed for heating.
Methane gas is created during the anaerobic breakdown of organic material in the wastewater treatment process. Although excess gas is burned in flares, we use most of it to produce energy in cogeneration systems at our Rock Creek and Durham facilities. The cogeneration system produces electricity and hot water for process and space heating in our treatment facilities.
Through cogeneration — the generation of electricity and other energy jointly— we meet 30% of the electrical energy needs at our Rock Creek facility and about 60% of the electrical energy needs at our Durham facility. Energy production at the Durham facility is enhanced using more than 150,000 gallons of fats, oils, and grease (FOG) delivered weekly from local restaurants. FOG, also known as “brown grease,” is cleaned out of restaurant grease traps and interceptors at regular intervals. In the past, this significant energy source was disposed of in landfills, but it is increasingly being used as feedstock to produce energy. The addition of FOG has doubled the amount of digester gas produced at Durham.
Through a public-private partnership with Tesla, a national provider of clean energy systems, solar panel projects at our Durham and Rock Creek facilities produce more than 500,000 kilowatt-hours of electricity per year.