Capstone Green Energy’s Microturbines Power Wastewater Treatment Plant

The City of Winona, MN, ordered two C65 integrated combined heat-and-power (ICHP) microturbines and a remote monitoring controller from Vergent Power, Capstone Green Energy’s regional distributor. The system will be installed at its wastewater treatment plant and double its renewable energy output at lower costs.

“The positive experience we’ve had with Capstone microturbines made it an easy decision to expand our system,” said Brian DeFrang, P.E., Public Works Director and City Engineer for the City of Winona. “The new equipment allows us to maximize the use of our digester gas while reducing our reliance on external energy sources. Taking advantage of the tax credit and grant before the programs ended was crucial in making this project affordable for our community. We’re proud to demonstrate how wastewater treatment facilities can operate more sustainably and efficiently.”

Capstone’s C65 ICHP microturbine burns the facility’s digester gas as fuel, producing consumable electricity, minimizing natural gas usage, lowering overall carbon emissions, and offering low-cost, resilient operation. The turbine’s exhaust energy will be recovered and converted into hot water, then fed into the digester’s process-heating loads.

C65 ICHP microturbine; image credit: Capstone Green Energy

The new turbines, set to be commissioned by April 30, will replace an existing C65 ICHP model that operated for over 15 years and had more than 100,000 hours of runtime. The Vergent controller allows the City of Winona to monitor Capstone’s CHP system, improving equipment visibility and energy sustainability.

Tax Credits

The City of Winona utilized a Federal Tax Credit and funding from the Department of Energy: the Industrial Training and Assessment Center Implementation Grant. This governmental support covered 90% of the project’s costs, allowing a significant power-capacity expansion at lower cost.

“We are excited for the City of Winona,” said Vince Canino, President and CEO, Capstone Green Energy. “Being able to leverage creative financing with government funds supports the intended outcomes of lowering carbon footprint in a responsible and sustainable way. This project embraces the idea of sustainability by converting multiple waste streams into a circular recycling continuum, all beginning with the receipt of the community’s wastewater. The City of Winona’s investment in renewable energy aligns with its long-standing dedication to sustainability, ensuring a greener future while minimizing operational costs.”

More Capstone News

In June 2023, Capstone Green Energy received an order via its Colombian distributor, Supernova Energy Services SAS, for a C1000 Signature Series microturbine. The unit was utilized at an industrial dairy farm in Colombia alongside an Alfa Laval steam boiler evaporator, generating 6,200 lbs. of steam per hour. Alfa Laval AB, a Swedish firm specializing in heat recovery products and a Capstone-approved network partner, collaborated on this project, which was commissioned in October 2023.

The energy system, running on high-pressure natural gas, supported the dairy’s pasteurization operations, while the Alfa Laval boiler supplied steam for the entire plant. The customer's decision to choose Capstone was influenced by reliability, minimal maintenance needs, and low emissions.

And in May 2023, Capstone Green Energy announced that its southern United States dealer, Lone Star Power Solutions, secured a contract with a West Texas energy company for an additional C800S Signature Series microturbine. This follows a 3.6-MW energy-as-a-service contract in early 2023.