Michigan regulators are investigating Consumers Energy Co. for broken meters, potential over-billing and delayed services.

The electric company has been under scrutiny for months because of power outages and rate increases. In February, more than 700,000 customers of Consumers and DTE Energy, a separate company, lost their power, some for more than a week, during a rare ice storm.

Now, the Michigan Public Service Commission — which regulates utilities — is investigating Consumers’ transition to advanced metering infrastructure from 3G technology to 4G in January 2023.

Customers have complained about ineffective natural gas meters and delays in new service installations. Some customers noticed their bills were higher than normal because the meters were not accurately showing the amount of electricity they used, according to Michigan regulators.

Consumers, which serves 1.8 million electric customers and 1.7 million natural gas customers in the Lower Peninsula, had been estimating bills for customers using the old 3G technology because the company could not determine actual usage since the meters displayed blank screens, according to the Public Service Commission.

State law prohibits energy providers from estimating bills for more than two consecutive months.

“Consumers Energy is committed to doing right by its customers and improving our performance and communications,” said Joshua Paciorek, spokesperson for the company in an email.

“We will cooperate with the commission on this effort and are focused on delivering the service our customers and the MPSC expect.”

The commission found that the company knew about the broken meters since 2020 but blamed them on battery contamination problems, which put over 900,000 meters at risk. The company failed to test them before switching to 4G technology, the commission found.

State regulators received 177 customer complaints about the company’s inability to provide new service in a timely manner. State law requires 90% of new service installations be completed within 15 business days.

As part of the investigation, the commission is seeking an explanation from Consumers Energy Co. by Aug. 4 about why the meters are malfunctioning and what they will do to fix them. The commission must respond with recommendations by Sept. 29.