Quinn says he supports the smart grid but believes ComEd and other utilities have already had big enough rate hikes to improve their infrastructures.
And he accuses the utilities of trying to do an end run around Illinois regulators by getting the legislature to override their decisions.
Quinn says this increase plus others ComEd has asked for would have raised the average customer's utility bill by 6 dollars a month.
"To allow the big utility companies to raise their hand and just raise their rates by hundreds of millions of dollars automatically without oversight by the people of Illinois, it's not a health thing," Quinn said.
In a statement ComEd said: "This bill would get the smart grid back on track and allow ComEd to build a modern grid to reduce power outages, give customers more choice and control over their energy use, and create thousands of much-needed jobs."
ComEd called on the legislature to override the governor's veto.