LANSING, Mich. (AP) -- Consumers Energy has been ordered to give electric customers a partial refund six months after Michigan's second-biggest utility was allowed to increase power bills.

The Michigan Public Service Commission on Monday authorized a $139 million rate increase, about $40 million less than what was authorized in May. Regulators say customers' bills will be about 1 percent lower than expected.

Regulators didn't approve executive bonuses factored into the rates and required the Jackson-based utility to spent money on tree trimming or refund the unspent amount.

Higher rates will continue to be partially offset with proceeds from the sale and decommissioning of a nuclear plant.

Regulators say rates will be more than 4 percent higher than in June 2008.

The company is a subsidiary of CMS Energy Corp.