2030 Objective: Generate or purchase 100 percent of all electricity for City operations from renewable resources
In FY 15-16, 100 percent of the electricity used by City operations came from renewable resources. This is the first time the City has officially reached this goal!
Seven percent of the City’s electricity use is generated by renewable energy systems on City facilities. The largest onsite renewable energy system in City operations is a “co-generation” energy system at the Columbia Boulevard Wastewater Treatment Plant (WWTP). Co-generation means using methane gas produced during the sewage treatment process to generate heat and electricity for the WWTP.
Fifteen City properties currently host solar arrays, ranging in size from 8 to 267 kilowatts, and representing nearly 700 kilowatts of solar capacity. That’s the equivalent of powering 140 homes annually in Portland. Four additional solar sites are in various stages of development. The City anticipates these coming online by the end of 2017.
The City purchases Renewable Energy Certificates(RECs) to account for the remaining electricity purchased from the utility companies. RECs offset the City’s use of fossil-fuel based power. In FY15-16, the City purchased 128,383 megawatt-hours (MWh) of Renewable Energy Credits, which represents 79 percent of the City’s overall electricity usage.
Renewable energy sources
Renewables generated or purchased
The Bureau of Environmental Services uses biogas generated at the Wastewater Treatment Plant to heat and power its operations as well as nearby businesses. This method of producing heat and power is called co-generation. The co-generation system delivers three main outcomes:
- The engine-generators supply about 40 percent of the wastewater plant’s electrical needs.
- The plant recovers heat from water and engine exhaust to use in its anaerobic digesters.
- The treatment plant also compresses some of its biogas and delivers it via pipeline to a nearby industrial facility to use for process heating.
The Portland Water Bureau has the City’s largest solar array on its Groundwater Pump Station. The 267.54 kW “Solar on the Slough” array is owned and managed by a third party. The array is an example of using a public-private partnership in order to build renewable energy systems on City facilities. Energy from the array provides power to the pump station.