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Ameren's community solar project at St. Louis Lambert International Airport

A plane flies over Ameren's one-megawatt community solar project at St. Louis Lambert International Airport, on Monday, August 12, 2019. The installation, which sells solar offsets to subscribed customers for an extra charge, began operation the week before. (Photo by Bryce Gray.)

Ameren aims to build the three largest investor-owned utility solar installations in the state, the electric utility said Tuesday, unveiling a plan to combine the projects with battery storage technology to improve reliability for local customers.

The St. Louis-based electric monopoly announced that it had filed plans for the solar-plus-storage installations with state regulators earlier Tuesday. If approved, the company said it hopes to have the projects — which would cost about $68 million, combined — in operation by the end of 2020.

“The installations will be the first-of-their-kind facilities in the state and among only a handful of solar-plus-storage facilities in the Midwest,” the company said.

The proposed installations target small, rural communities, including Green City and Utica in northern Missouri, and Richwoods, about an hour southwest of St. Louis. Each of the communities are located on parts of the grid where transmission is vulnerable to prolonged power outages, Ameren officials said.

“Just because of the geography, it can take four, five, (or) six hours just to get the lights back on (in those places),” said Kevin Anders, Ameren’s vice president of operations and technical services. But once implemented, he said the projects would address those local issues of reliability, while minimizing intermittency.

At 10 megawatts apiece, Ameren said the projects would be the largest investor-owned solar facilities in Missouri.

Combined, the facilities would be capable of meeting the power demands of roughly 10,000 customers, the company said. Fully charged, the accompanying battery system would be able to power 2,000 to 3,000 homes for about four hours at peak usage — like on a hot summer day, with air conditioners blasting. In less extreme conditions — say, on a day with temperatures in the 70s — the battery power could last for twice as long, Anders said.

The projects will feature bifacial solar panels capable of generating power from both sides — something that can boost power generation when installations sit atop light-colored surfaces, including stones.

The dual, solar-and-storage approach could become more common as Ameren works to add more solar energy in the future, Anders said.

“I think it will become more prevalent,” he said, referencing the company’s plan to add 100 megawatts of solar by 2027. “As the technology evolves and advances and becomes more economical, this is certainly one application that we could apply at more sites on our systems.”

The effort is touted as part of Ameren’s bigger plan to add renewable energy generation and reduce carbon emissions 80% by 2050, from 2005 levels. Though specifics have not been divulged, the company has said it is open to exceeding that goal — something that would need to happen to be consistent with emissions reductions demanded by the latest climate science warnings.

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