Illinois regulators are raising questions about plans for a controversial power plant. They say the so-called “clean coal” project would hike electric bills across the state.

Building any new power plant costs money, and ratepayers would pick up much of the tab. The question is how much, and whether the Taylorville Energy Center’s environmental benefits justify the price.

The Illinois Commerce Commission finds electricity from the plant would cost substantially more than power from other sources. And commissioners say the benefits are uncertain.

The ICC sent its analysis to legislators yesterday. The report says residential bills would likely rise about 2 percent - more for commercial customers.

An official with Tenaska, the company behind the plant, says it’s worth it to get relatively clean power, and a market for Illinois coal. He says the state needs to invest in generating capacity, or pay much higher prices later.

The Taylorville plant would turn the coal into synthetic natural gas, and capture much of the carbon dioxide.