Reif, in a filing with the Public Utilities Commission, said he favored the bidding exemption because independent power producers have provided the last 2,000 megawatts of capacity built in Colorado.

But Reif also suggested that the commission set a cap on how much Xcel could spend on the proposed plant.

"There should be some cap on the amount that the utility is able to recover from ratepayers," he said. "It shouldn't be a blank check." Xcel claims it can build the 750-megawatt expansion of its existing Comanche generating station in Pueblo cheaper and faster with an exemption from state bidding rules. Xcel said if the project is opened up to competitive bidding, it could add an extra two years and cost the company up to $236 million more.

If Xcel's request is approved by the PUC, the company said it would begin charging residential customers an additional fee of approximately 89 cents per month to cover financing and construction costs starting in January. Fees could increase in 2007.

Reif's filing was one of 11 made Monday.

Four members of the Colorado Independent Energy Association, a group of unregulated power producers, filed testimony against Xcel, saying they were ready to place competitive bids on the project.

State rules require competitive bids for the construction of any power station of more than 250 megawatts.

"Our goal is to have Xcel stick to the rules, to not try to bend them," said Nick Muller, executive director of the group.

Several environmental groups filed testimony against Xcel, claiming competitive bids would result in a cleaner-burning and less costly plant.

"We don't accept the presumption that a coal-fired power plant of this size is necessary for Colorado," said Mark Detsky, staff attorney for Environment Colorado, a nonprofit conservation group in Boulder.

"The way that it is proposed, it's a bad deal for ratepayers who are on the hook for all the risks and costs of this plant before it gets built," he said. "The competitive bid waiver goes against all the market forces that are in place to make sure that ratepayers get the best deal, and that's in addition to the environmental horror it will cause." If the bidding waiver is granted, Xcel estimates it can have the plant operational by late 2009. But Xcel said it won't go forward with the Pueblo expansion if the waiver is not granted.

"We simply could not do it if we're not given the waiver," said Xcel spokesman Steve Roalstad. "We have put together a sound proposal that takes into consideration many different needs and wants from our customers." The PUC expects to make a decision by the end of the year.