Montana city flips switch on 545 kW municipal solar facility


Ameresco, an energy efficiency and renewable energy system installer, announced the electrification of a 545 kW behind-the-meter solar photovoltaic (PV) array for the city of Missoula’s wastewater treatment plant.

At a “flip the switch” event held in the Montana city this week, officials christened the municipal solar project, which Ameresco will maintain under a 25-year solar energy agreement that had zero upfront cost to the municipality, the companies said.

The solar facility consists of 948 ground-mounted panels and represents the largest behind-the-meter solar project in Montana to date. The facility is projected to produce 700,000 kWh each year of clean energy and offset about 20% of the wastewater treatment facility’s energy consumption, saving the city $7,000 per year in energy costs and 8,000 tons of CO2 emissions from being burned.

“Our city has a long track record of implementing forward-thinking conservation and climate change measures and the completion of the solar PV array at our wastewater treatment facility is another demonstration of our commitment to sustainability,” said Ross Mollenhauer, engineering manager for Missoula.

Construction of the facility began in the Summer of 2022 and completed in March 2023.

In January 2013, the Missoula City Council adopted the Conservation and Climate Action Plan (CCAP) with a goal of becoming carbon neutral by 2025. As part of the CCAP, the city implemented a number of initiatives and projects to support citywide decarbonization.

As a non-export solar PV system, electricity generated by the solar system will be consumed on site, reducing operating costs and emissions associated with the wastewater treatment processes.

Montana is ranked 30th in the U.S. for renewable energy generation, with more than 1.5 GW of wind, solar and storage capacity reserves, while the state sees just shy of 15% of its electricity produced by renewables, according to American Clean Power. Yet through Q4 2022, Montana was ranked 44thin the country for solar, with only 133 MW of installed capacity, or enough to power 17,410 homes, according to the Solar Energy Industries Association.

The state’s largest investor-owned utility, NorthWestern Energy, has historically fought the development of solar projects in excess of 5 MW to date, with developers typically embroiled in litigation over the cost imparted on the utility for distributed solar projects and small utility projects in the Big Sky state.

Ameresco, based in Framingham, Mass., is a 23-year old energy efficiency, renewable gas, solar and energy storage systems company which has built projects for the municipal and state governments, universities and hospital market. As of December 31, 2022, Ameresco owned or operated 132 solar and battery assets out of a 162 total power plant portfolio.

In 2022, Ameresco reported $1.82 billion in total revenue, up from $1.21 billion in 2021. The company reports about 7.4% of its annual revenue comes from the sale of solar products and systems as well as energy management solutions.

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