NorthWestern Energy Awards Energy Efficiency Incentive for Wastewater Facility Upgrades
image credit: Wastewater treatment plant in Billings, Montana. Credit: Billings Public Works
- Oct 23, 2020 4:16 pm GMTOct 23, 2020 12:55 pm GMT
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NorthWestern Energy awarded Billings, Montana, $90,000 as energy efficiency incentive for energy improvements at the city’s wastewater treatment plant.
Over the past three years, the city has invested $75 million to upgrade the facility, including constructing an aeration system that maximizes energy efficiency. Aeration is the most energy intensive process required in wastewater treatment, accounting for around half of the electrical load.
The new aeration system uses turbo blowers that rotate at speeds of over 30,000 rpm. These high speeds allow the rotating shaft to levitate creating very little friction resistance and resulting in lower energy requirements. Additionally, a new automated control system incorporates a "most open valve" technology. The new control system interfaces with dissolved oxygen probes in the aeration tanks to control the inlet valves serving each basin. The control system operates the blower/aeration system at the minimum possible pressure by operating in a “most open valve” condition.
The Billings aeration system upgrades are estimated to save about 743,000 kilowatt-hours per year, resulting in about $57,300 in annual electric cost savings.
The project was initiated by a team made up of City of Billings staff, NorthWestern Energy representatives and consultants.
During the last 10 years, Billings has implemented 62 energy efficiency projects, qualifying for $967,050 in energy efficiency incentives from NorthWestern Energy. These projects resulted in an estimated 5.82 million kWhs saved per year, equal to about $455,000 in annual electric cost savings.