LANSING, Mich. (Michigan News Source) — Just when Consumers Energy thought it had found a clean break for its hydro fleet, six dams turned up with a temperature problem that could chill the entire sale.

State filings with the Federal Energy Regulatory Commission show the Alcona, Croton, Foote, Hodenpyl, Mio, and Tippy dams consistently send warmer-than-allowed water downstream. Those temperatures are high enough to harm cold-water fisheries. Michigan’s Department of Environment, Great Lakes and Energy (EGLE) says it is “unlikely” to sign off on the next round of water-quality certifications unless the problem improves.

Compliance needed.

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In an October letter to federal regulators, EGLE engineer Douglas Bridges wrote that the state cannot consider the issue resolved until temperatures fall back into compliance. Without those certifications, the Federal Energy Regulatory Commission (FERC) can deny hydropower licenses altogether.

That raises the stakes for Consumers’ pending sale to Confluence Hydro, a Maryland-based subsidiary of Hull Street Energy. Confluence would take over operations while Consumers buys back the electricity at nearly double its typical rate—an arrangement the utility defends as a way to shed long-term liabilities.

Consumers installed cooling systems at each of the six problem dams, but federal filings show the upgrades barely moved the needle. Downstream water remained more than two degrees warmer on average, which is still out of bounds.

Michigan’s fish stocking.

The Department of Natural Resources (DNR), which spends more than $1 million annually stocking fish downstream of the warm-water dams, says the ecological risk is real. Trout and other cold-water species cannot survive in the higher temperatures.

The proposed sale is already under review at the Michigan Public Service Commission, where environmental groups, tribes, the Attorney General’s Office, and local associations are pushing to scrutinize repair costs, relicensing costs, and potential removal costs. Some argue dam removal may be cheaper and safer than continued operation under a private owner.

Confluence Hydro says it plans to “maintain, upgrade, and relicense” the dams and is hearing from many residents who want the reservoirs preserved.