City of Salem upgrades biogas cogeneration system

By City of Salem, Oregon | November 05, 2018

The city of Salem, Oregon, is very pleased to announce the receipt of $3 million in renewable energy incentives from the nonprofit Energy Trust of Oregon.  This is in addition to $200,000 in project development incentives previously received from Energy Trust, and $3 million in grant funds awarded by Portland General Electric’s Renewable Development Fund in 2017.  In all, these contributions cover over half of the total costs the city needs to upgrade the Willow Lake Cogeneration Facility at the Wastewater Treatment Plant. Remaining project costs will be paid for through existing water and wastewater utility rates.

The existing cogeneration facility at Willow Lake has been producing clean, renewable energy from the byproducts of the wastewater treatment for more than 50 years.  As wastewater moves through the treatment process microorganisms break down or digest the organic matter.  As this digestion occurs, methane and other gases (biogas) are produced.  At many treatment plants, these gases are simply flared to the atmosphere.  Through the cogeneration process, however, this biogas is captured and put to use, producing renewable energy. Willow Lake is one of only 11 facilities in the state of Oregon that is presently using biogas to produce renewable energy. 

According to Salem Mayor Chuck Bennett, “This really is a very exciting project, and one that I’m quite proud of.  It is this kind of effort and ingenuity that demonstrates Salem’s commitment to environmental action.” The energy incentives the City has received from both Energy Trust and PGE will finally allow aging infrastructure at the cogeneration system to be replaced and upgraded with a more efficient, larger operating system, an improved gas treatment system allowing for cleaner emissions, and a new cogeneration building with capacity to expand with a second engine in the future to take advantage of future biogas production growth.   

Once complete, the upgraded cogeneration facility will supply nearly one half of the total power needs at the wastewater treatment plant.  This significant upgrade is expected to save the City of Salem $300,000 each year, and keep 5,000 metric tons of pollution causing gases from being released into our atmosphere. Waste heat from the facility will also be used to heat the treatment plants administrative building.  This leads to an additional estimate of $30,000 per year in natural gas savings. In all, the amount of renewable electricity produced from the cogeneration facility will equal the amount that is needed to power nearly 900 homes.  “With this investment, the city of Salem is transforming unwanted waste into valuable clean energy to be used on site,” said Dave Moldal, renewable energy program manager, Energy Trust. “This innovative cogeneration facility will help the city reduce energy costs and deliver more value to residents of Salem, Turner and Keizer.”

Energy Trust’s incentive of $3 million will be paid in installments to the city with $500,000 paid when the project reaches commercial operation and the remaining funds will be distributed as the city’s new cogeneration system meets renewable energy generation milestones. Facility upgrades will begin this winter, with an anticipated completion in late 2019 or early 2020.

This project has been made possible by the generous support of Energy Trust of Oregon and customers participating in Portland General Electric’s Green Future Program through the Renewable Development Fund.