Every night for months, turbines at Missouri's largest wind farm sit idle to avoid killing endangered and threatened bats.
Now, as the wind farm's owner, Ameren Missouri, seeks permission to increase customers' rates, consumer advocates are sounding the alarm. They argue customers shouldn't have to pay the full costs of the wind farm on their bills if it's not fully functional. And at least one fears the company won't meet state standards for renewable energy.
The St. Louis electric utility purchased the High Prairie Renewable Energy Center near Kirksville from a developer and started operations last year. The 175-turbine facility should produce up to 400 megawatts.
But according to testimony filed with regulators who are expected to decide on Ameren's requested rate increase, High Prairie is not producing at full capacity.
"To be clear, the High Prairie Wind Farm has been curtailed from before dusk to after dawn since April 19, 2021," Geoff Marke, chief economist for the Missouri Office of the Public Counsel, said in sworn testimony filed last week with the Missouri Public Service Commission.
Ameren halted night operations for several weeks this spring after four bats, which are nocturnal, and 52 birds, including a bald eagle, were discovered dead on the property, according to a report submitted to federal wildlife officials.
It received a permit in May from the U.S. Fish and Wildlife Service to operate in a way that seeks to minimize the number of endangered or threatened bats it kills each year. But bats kept turning up on the property.
So despite Ameren's good faith efforts to protect the bats, it voluntarily stopped running the turbines at night in June, said Karen Herrington, a field supervisor for the Missouri Ecological Services Field Office of the USFWS.
It's the only wind farm in Missouri that Herrington said she is aware of that has had to stop operating at night to avoid bat kills.
Ameren is seeking a rate increase from customers worth nearly $300 million, including costs from High Prairie it hopes to recover from ratepayers.
But consumer and business advocates filed testimony estimating the wind farm is only operational about 75 percent of the year. They want Ameren to recoup far less of those proceeds.
"To the extent that you have to reduce the output or reduce the operating times of the wind farm so that you're not running it at night, ratepayers should not be on the hook to pay a return for an asset that can't fully operate," said Greg Meyer, a consultant who testified before the PSC on behalf of Missouri Industrial Energy Consumers.
Beyond that, Marke said in testimony, Ameren is at risk of failing to meet a state requirement that, starting this year, utilities generate at least 15 percent of their power from renewable resources.
In a statement, Ameren's chief renewable development office, Ajay Arora, said the company stands alongside supporters of clean energy and said growing solar and wind power benefits customers. Achieving net-zero carbon emissions, which Ameren has pledged to do by 2050, "will require significant investments in new wind and solar facilities."
High Prairie, Arora noted, has been operating for nine months.
"It operates every day for the benefit of all of our customers, and we anticipate it will continue to do so for decades to come," Arora said. "Throughout siting, construction, permitting and now generating clean energy at High Prairie, Ameren Missouri has worked closely with U.S. Fish and Wildlife Service and the Missouri Department of Conservation."
High Prairie history
Ameren first sought approval in 2018 for the High Prairie wind farm, which sits in Adair and Schuyler counties in northeast Missouri.
Even at that time, some groups raised concerns about the location, given the prevalence of the endangered Indiana bats and threatened northern long-eared bats, both listed by USFWS. The wind farm's USFWS permit also covers the little brown bat, which is not listed federally but is a "species of conservation concern" for the Missouri Department of Conservation.
"If Ameren Missouri's project results in fatalities of vulnerable, endangered or protected species, Ameren Missouri could be liable for financial penalties and potential enforced curtailment of generation, which in turn could raise future prudency concerns and would almost certainly include greater scrutiny of future wind projects," Marke said in testimony in 2018.
Herrington said while USFWS doesn't have a role in determining where wind facilities can go, the service informed Ameren the site was a high risk location because of the prevalence of Indiana bats.
Federal data show seven Indiana bats have died on the premises since Ameren received its permit. Given the size of the property, there are likely to be more. The company is expected to file a report next week with USFWS to estimate its impact on birds and bats in the area.
Both OPC and the Missouri Industrial Energy Consumers are advocating customers pay a much smaller share of the High Prairie than Ameren proposed in its rate filings.
Marke said in testimony he feared the reduced hours the wind farm can operate might mean Ameren fails to obtain its renewable energy standard, the state law requiring that it obtain 15 percent of its power from renewable sources.
"As such, I do not believe ratepayers should be responsible for any costs related to Ameren's poor managerial decisions in electing to site its wind farm where it did," Marke said.
Only 75 percent of the nearly $600 million in costs from the wind farm should be recovered from ratepayers, he wrote.
MIEC, represented by Greg Meyer, proposed cutting more than $8 million from the return Ameren is asking to receive on the investment.
The PSC is months away from hearing Ameren's rate case, and new rates won't take effect until next year.
The Missouri Independent is a nonprofit, nonpartisan news organization covering state government and its impact on Missourians.