DTE Energy is asking state regulators for a $205 million increase for natural gas.

Michigan Attorney General Dana Nessel says that's the equivalent of an 8% increase on customers' bills and calls it "excessive and unreasonable."

Nessel says she appreciates that utilities need money to maintain and improve natural gas infrastructure. But she says DTE can do that with a $65.5 million dollar annual increase.

And she says state regulators should make sure commercial customers of DTE are paying their fair share of that increase, rather than placing more of the burden on residential customers, which is currently the case.

Utility watchdogs say rates for both natural gas and electricity are going up much faster than the rate of inflation almost every year, which results in unaffordable energy bills for many customers.

Don Kesky is with the Public Law Resource Center. He says utilities typically file a new rate increase directly after getting one approved. And each increase is layered on top of the last, resulting in compounding the costs on people's bills.

He says it's also a problem that state regulators allow utilities to make rate requests based on their own estimates of future costs.

"If you overdo these projections, and you grant too high of a rate increase year after year, you also reduce discipline to control costs," says Kesky.

DTE Energy also requested a 10.5% rate of return, or profit. Kesky says if the utility manages to make more of a profit than that, customers are not eligible for a refund; it is locked in to the utility's revenue.

DTE did not respond to a request for comment.

Editor's note: DTE Energy is one of Michigan Radio's corporate sponsors.