Ameren Illinois

ERIC BUENEMAN / FLICKR.COM/N0UIH (CC-BY-NC)

Environmental groups are criticizing Ameren Illinois for what they describe as backing away from energy efficiency goals.

Flickr User James Bowe / "Lightbulb" (CC BY 2.0)

The Illinois Commerce Commission has approved a rate decrease for ComEd and rates increase for Ameren Illinois.

ComEd says the lowered delivery rate announced Wednesday is the result of efficiencies generated from the continuing rollout of its smart grid. The rate decrease is expected to mean the average residential customer should pay about $1 a month less on their bill, starting next month.

The commission approved a $67 million rate decrease -- $17 million more than the $50 million decrease ComEd proposed.