In public testimony, a Consumers Energy employee admitted that relying too much on intermittent renewable energy sources could mean the company won’t generate enough electric power to meet customer demand at times. Among other things, this could mean the company imposes “demand response” on customers. Such measures often include charging higher prices during peak use periods, but the definition also extends to rolling blackouts and involuntary rationing.

Consumers Energy says that under its renewable energy action plan, it will stop using more reliable conventional energy sources by 2040.

Sara T. Walz, an engineering analyst for Consumer’s Energy, submitted testimony to the Michigan Public Service Commission about the company’s integrated resource plan, which outlines its future. Under the Integrated Resource Plan, Consumers Energy would replace most electricity generated by coal, gas and nuclear plants with intermittent renewable sources, including wind and solar. Walz stated:

“The results of the electric supply reliability studies show that dependence on so many intermittent sources of generation results in significant periods of time for which the potential loss of load may occur," Walz said.

“Loss of load” is an industry term for when a company cannot produce enough electricity to meet customer demands.

Jason Hayes, director of environmental policy at Mackinac Center for Public Policy said, “They’re admitting that closing reliable energy sources, like coal and nuclear – which they plan to do by 2025 – and building solar will ensure customer demand regularly pushes their fragile, renewable-heavy system to the brink of failure.”

Katie Carey, director of media relations at the utility’s parent company, CMS Energy, said a combination of these power sources and demand response measures will lower peak customer demand and “comprise 90% of electric capacity by 2040.” She said the company also plans to buy four existing natural gas-fired power plants to supply power when solar and other renewable sources are not producing.

But Hayes notes that under the utility company’s 2021 Clean Energy Plan, Consumers Energy intends to stop using these four additional plants by 2040. He says this will significantly increase electricity rates, further reduce reliability and inevitably lead to outages and blackouts similar to recent events in Texas, California and Great Britain. In these and other places, he said, governments have ordered a phaseout of reliable fossil fuel and nuclear-powered electricity production.

Editor's note: The headline was altered on this article after publication.