In FY 17-18, City operations again met its goal of supplying 100 percent of the electricity used by City operations from renewable resources.
Nine percent of the City’s electricity use is generated by renewable energy systems installed 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 entails using methane gas produced during the sewage treatment process to generate heat and electricity for the WWTP.
Seventeen 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.
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 FY 18-19, the City purchased 112,054 megawatt-hours (MWh) of Renewable Energy Credits, which represents 77.7 percent of the City’s overall electricity usage. The RECs are sourced from wind facilities in the western United States, including 20,815 MWh from Alaska’s only commercial wind project. Located at the gateway to Chugach State and National Parks, Fire Island Wind project provides an energy resource that eases strain on dwindling natural gas supplies in Cook Inlet and provides clean, viable, reasonably-priced new energy source for Southcentral Alaska.
In 2017, the City (and Multnomah County) established a goal to meet 100 percent of community-wide energy needs with renewable energy by 2050 (Resolution 37289). The resolution prioritizes the purchase of renewable resources over the purchase of RECS, with the intention of reducing reliance on RECs during the transition to 100 percent renewable resources over time. With this in mind, BPS has entered into a 15-year agreement with Portland General Electric to participate in its new Green Energy Future tariff, in which the City will purchase 46,600 MWh of Oregon-based solar energy annually beginning in 2021.
Renewable energy sources
Renewables generated or purchased
Portland Fire and Rescue (PF&R) completed the City’s first solar + battery storage project at Fire Station 1 in December 2019. The downtown location serves as an incident command post and houses the office of the Fire Chief and other administrative functions. The design includes a 30kW solar array paired with lithium ion batteries to provide flexibility during a prolonged power outage by supplementing the existing generator on the site. The project is receiving grant funding from Portland General Electric through both the Renewable Development Fund and a Research & Development grant. In addition, the City is partnering with Portland General Electric to develop the battery technology and software solution as part of a PGE demand response pilot.
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 was constructed, owned and managed by Bonneville Environmental Foundation for six years and was recently purchased by the City. 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.