How a Wastewater Plant Hits Net Zero Energy

A wastewater treatment facility in Gresham, Ore., went beyond net zero energy consumption within 10 years after beginning the journey.

While other cities across the country are working to mitigate the exorbitant amount of energy their wastewater treatment plants consume, the city of Gresham, Ore., has found a way to achieve net zero energy consumption.

Through a 2005 partnership with a private contractor, Gresham's wastewater treatment plant began the process of green energy creation as well as reducing their overall energy consumption. A mere 10 years later, in March 2015, the plant hit net zero for the month, proving they could create as much energy on site as they needed to consume for operations. It was a milestone victory for the city.

Reaching Net Zero Energy Means Reusing Resources

The first to minimizing energy costs was investing in the right tools that would help the plant harness what it already had: methane gas, and plenty of it. In 2005, the city installed its first biogas generator, which would allow the plant to convert methane gas that naturally exudes from wastewater into energy. Five years later, the facility installed solar panels to add to the green energy they were producing.

In 2012, the wastewater plant began accepting restaurant waste, which includes fats, oil and grease, and harnessed the energy by turning the sludge into biogas. This move helped double the facility's production of biogas, and eventually helped push the plant towards its goal of net zero energy.

Net Zero status at Gresham's wastewater treatment plant


Partnership is Crucial to Meeting Net Zero Goals

When the idea of moving the wastewater facility towards energy independence first took shape, city officials knew they would need a partner in the process. After much consideration, they landed on Veolia North America, based on their past success and panel of experts.

We like to solve environmental problems at Veolia, like helping to reduce energy usage. In Gresham, we can combine Veolia’s technical expertise with the city’s vision and its local knowledge. And we’ve helped the city turn its largest energy user into a plant that not only produces its own energy, it exports energy."

With the help of Veolia, the Gresham water treatment facility went from a monthly energy bill of $50,000 to $0.

Net Zero Energy is a Replicable Achievement 

Gresham was the second city in the country to reach net zero energy for its wastewater treatment plant, an idea city officials don't think is impossible for others to reach.

Here’s the awesome thing. What we did here is not a secret formula. It is replicable at thousands of treatment plants all over the United States.

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