Workers install a 0.5-megawatt solar array in St. Charles. Illinois. Credit: City of St. Charles / Flickr / Creative Commons

The arrays don’t significantly impact the grid, but officials say they’re one component of a diversifying power portfolio.

The Illinois Municipal Electric Agency in January announced plans to commission new solar arrays in three of its member cities, an addition to two arrays it commissioned in recent years. While the panels provide a relatively small amount of power to the municipalities, officials say they’re a valuable opportunity to experiment with new ways to diversify their power sources.

Construction is planned to begin this summer on a 0.5-megawatt array in the southern Illinois city of Altamont, a 1-megawatt array in the northwest Illinois city of Rock Falls, and a 1-megawatt array in the western Chicago suburb of Naperville.

Developers will build and own the solar arrays, selling the power they produce through power purchase agreements to the agency. Distribution lines are the responsibility of the host city.

IMEA allowed any of its 32 member municipalities to submit proposals to host the arrays, Staci Wilson, the agency’s director of government affairs, said via email. Application review considered the property available, ability of the local distribution system to support the project, and local support for the project, she said.

Illinois’ municipal utilities aren’t included in the state’s long-term renewable procurement plan, so they aren’t held to renewable goals the way the state’s regulated utilities are. But Wilson said IMEA is working to invest in more renewable resources.

Currently, IMEA has a contract to purchase 70 MW of wind through 2030 from the Lee-DeKalb wind farm owned by FPL Energy Illinois. Wilson added that the agency just finalized another long-term contract, set to begin later this year, to procure 50 MW of wind from a forthcoming Geronimo Energy site. And two of the agency’s member municipalities, Peru and Rock Falls, operate run-of-the-river hydroelectric generation operations totaling about 10 MW of capacity, Wilson said.

According to the agency’s website, IMEA also owns just over 15 percent of the southwest Illinois-based Prairie State coal-fueled power plant, and about 12 percent of the Trimble County 1 and 2 coal-fueled plants in northern Kentucky.

The St. Charles array has produced 982 megawatt-hours of electricity since September 2017.

Demonstration solar projects like the ones just announced — which incur minimal cost for the agency and municipalities — are a chance for IMEA and its members “to get real experience in developing a project and studying the solar energy output of the facilities,” Wilson said.

The agency already has some experience with solar arrays like the forthcoming ones. A 1-megawatt array in the central Illinois city of Rantoul has produced 3,330-megawatt-hours of electricity since coming online in December 2016. And a 0.5-megawatt array in the northeast city of St. Charles has produced 982 MWh since beginning operations in September 2017.

Both of those arrays are owned and operated by Altorfer Cat, which negotiated 20-year power purchase agreements with IMEA. The agency also has the option to buy the arrays themselves after six years, Wilson said.

This type of agreement is the most economical for all parties, said Tom Bruhl, the manager of St. Charles’ electric utility. The 30 percent tax credit that Altorfer receives from the federal government for owning the arrays — which isn’t available to municipalities or IMEA — means the company can factor it into its electric contract with the agency, Bruhl said.

He acknowledged that the roughly 4,800 panels, sitting on a three-acre patch of land in the industrial southeast quadrant of St. Charles, don’t significantly impact the city’s electric grid. This past summer, city demand peaked at about 117 megawatts, he said, comparing the capacity provided by the solar array to that of a Super Target. So from that standpoint, “it’s very difficult to see going 100 percent solar,” he said. “Where do you have that much acreage?”

But on the other hand, he added, that area of the city uses significant load. So the array, which is next to a substation, is ideally located since he didn’t have to worry about installing distribution lines. (The city of Rantoul spent about $8,000 on a distribution line to connect its array to the grid, Greg Hazel, Rantoul’s director of public works, said via email.)

This is also a valuable resource for the city’s residents, Bruhl said. He takes at least two calls a month from people interested in learning more about the operation, perhaps considering installing solar panels on their own houses. Now that he and his staff have been involved in the planning and maintenance of the city’s array, albeit bigger than a rooftop array, he can help residents plan, he said. He also receives calls from other cities interested in pursuing similar projects. That included Naperville, one of the three cities set to receive its own array later this year.

A 0.5-megawatt solar array sits on a three-acre patch of land in the industrial southeast quadrant of St. Charles.

The St. Charles development and planning process, which took place over a year and a half, was relatively straightforward, Bruhl said. Altorfer’s engineers had to ensure the panels were far enough out of the shadow of a 30-foot-tall building to the south, and for the same reason, Bruhl’s team had to remove several evergreen trees they had planted in the area.

The DuPage Airport also happened to be nearby, which meant developers had to clear the site with the Federal Aviation Administration to make sure the glare from the panels wouldn’t obstruct visibility for pilots during takeoff and landing. If that had been a problem, it could have derailed the project, Bruhl said.

While these solar arrays don’t generate large amounts of capacity for the cities, Wilson said the agency’s member municipalities “wanted solar arrays in their hometowns in order to demonstrate their commitment to the environment while gaining experience on how to build, commission and maintain solar facilities and move forward into the future.” The agency is in discussions now to purchase electricity from larger-scale solar generation projects, she said.

IMEA’s members are on an all-requirements contract with the agency, so they can’t seek power from other sources on their own, Bruhl said. But he added that he sits on IMEA’s board along with representatives from each of the other member municipalities.

“We are very supportive of pushing staff to seek opportunities to diversify our portfolio more into renewables,” while also ensuring contracts don’t raise costs for residents, he said. “The model is that we will continue to drive IMEA to diversify their portfolio as prudently feasible with renewables.”

In the meantime, he said the array in St. Charles has allowed him and his staff to become a community resource, particularly for residents interested in installing solar on their own homes. “Having that demonstration project out there and gaining that experience pays that forward to all of our customers.”

David Thill

David is a New York-based journalist who has written on health, science and the environment for various outlets, including World Wildlife Fund and the Chicago newspaper Windy City Times. He has reported...