BOULDER - Residents in Boulder should get one more chance to vote on the potential cost of the city's plan to create a municipal utility if it goes forward, a spokesman for a new Boulder group said.

The five-person group - called the Voter Approval of Debt Limits group - hopes to put a question on the November ballot that would require voter approval before the city of Boulder could issue bonds to purchase Xcel Energy Inc.'s electric distribution system, and would put a cap on the amount of debt that could be issued, said Phil Fox, a group spokesman.

The group has 90 days to gather about 6,000 signatures needed to put the question on the ballot, Fox said. Boulder may need to pay as much as $500 million to buy existing electricity infrastructure, Fox said.

"I don't care if Boulder has new debt, but we feel very strongly that it should have voter approval," Fox said.

Boulder resident John Spitzer - a supporter of plans to create a city-run utility - said that such a vote would "muddy the waters" and could end up costing millions of dollars. Spitzer and other supporters are discussing whether or not to mount a counter-petition, he said.

"An election on this issue essentially kills municipalization because it kills bonds at that point," Spitzer said. "Voters approved this a year and a half ago. Why do they have to approve it again?"

The group, made up of volunteers, hopes to raise money to support the petition drive, Fox said. The group asked Xcel Energy for support, but has not heard back, Fox said.

Xcel spokeswoman Michelle Aguayo said Xcel Energy always has believed that another vote would be a good idea. No decision has been made about whether or how to support the petition group, she said.

"We have discussed with the proponents their proposal and are taking it under consideration," Aguayo said.

The new petition group also wants to limit the fees paid to bankers who manage the sale of the bonds in any municipalization effort, Fox said.

Boulder voters in November 2011 narrowly approved two ballot measures. One allows the city to explore creating its own electric utility; the other created a budget of $1.9 million annually for five years to pay for related work. A Boulder City Council vote on whether or not to move forward with municipalization is expected in August, based on a schedule created by the council.

According to state law, Boulder would not be able to start condemnation proceedings on Xcel Energy's electricity infrastructure assets if it is not prepared to pay at least its offering price. If paying for the assets is contingent on another vote by residents, it could complicate negotiations.

The new petition also calls for the city's utility service area to not extend beyond city limits unless voters in those areas also are allowed to participate in debt elections. About 5,800 households in unincorporated Boulder County could be covered on the city's new electrical grid, although but they did not vote in the November 2011 on the municipalization issue.

Those households are the subject of an Xcel Energy petition filed Thursday with the Colorado Public Utilities Commission. Xcel wants the PUC to confirm that it is the governing body that decides who can serve those customers, not the city of Boulder, according to an Xcel press release.

"Our customers outside the city limits had no say in the matter of Boulder's pursuit of a municipal utility," Jerome Davis, regional vice president for Xcel Energy, said in the press release. "The best way we can protect them is to ask the commission to clarify its authority."