Michigan's biggest power utility can raise customer bills, starting Friday, after regulators approved a rate hike that is about half of what was sought.

The $188-million increase by DTE Electric, which has 2.2-million customers in southeast Michigan, is about $4 a month for a typical residential customer using 500 kilowatt-hours of electricity.

The state Public Service Commission said the impact will be softened temporarily when the utility passes along $30- to $40-million in relief because it is spending less on fuel to generate.