SALT LAKE CITY — Enough communities in Utah and elsewhere have agreed to purchase nuclear power from a small modular reactor planned at the Idaho National Laboratory, triggering a next phase in its development.

Participating members in the Carbon Free Power Project signed contracts that total more than 150 megawatts, which means there will be an increased focus on site characterization and preparing a license for the U.S. Nuclear Regulatory Commission.

Touted as next generation technology in delivery of nuclear power, the small modular reactors developed by Oregon-based NuScale would be the first of its kind in the nation, made up of 12 individual 60 megawatt modules. The anticipated gross output is 720 megawatts of electricity — enough to power 750,000 homes.

The Carbon Free Power Project, or the planned nuclear facility, is a project of the Utah Associated Municipal Power Systems and includes 34 participating members, mostly cities.

The Utah Associated Municipal Power Systems, a political subdivision of the state of Utah, is made up of cities and special service districts in six states. It was established to provide power, transmission and other electrical-related services on a nonprofit basis.

Most cities are adding nuclear to their energy portfolio as a hedge against market volatility with natural gas prices, to counter a regulatory upset that would phase out coal and to add to their renewable sources of electricity.

Ultimately, the nuclear power could help them generate a carbon free energy platform.

Utah Associated Municipal Power Systems officials say the nuclear component for cities typically hovers in the 5 to 10 megawatt range and is not a big piece of their portfolio, but cities could always opt to buy more.

The project is backed heavily by the U.S. Department of Energy, which gave NuScale a competitive award of $226 million in 2013 to develop the technology. Two years later, the federal agency gave NuScale $16.7 million for licensing preparation.

Two of the modules will be used by the agency's Idaho National Laboratory in support of research and also to deliver power to the sprawling facility occupying more than 800 acres outside of Idaho Falls.

The small modular reactor technology planned for Idaho is signficantly smaller than a traditional nuclear power plant, about one-third the size, and is touted for its advanced safety features, including self-cooling and automatic shutdown.

But critics say the new untested technology may end up costing municipal ratepayers millions in the long run, and there are cheaper alternatives that won't generate nuclear waste.

HEAL Utah commissioned a study that it says shows several alternative scenarios that are much less costly and don't involve investment in a "high-risk" project.

Douglas Hunter, CEO and president of the Utah Associated Municipal Power Systems, said there are several contractual "off-ramps" built into the project that allow both the municipal power association and its member cities to walk away.

Before the next application is submitted to the U.S. Nuclear Regulatory Commission, the association will have to agree to go forward and participating members can agree to proceed, or back out.

"We took it seriously that we didn't want to be caught in some sort of death spiral for the cities," Hunter said.

The association is also going through additional financial modeling that Hunter says would trigger another exit ramp should costs hit a certain level.

"We're very concerned about cost overruns and competitiveness. We set up our contractual structure to give everyone that assurance that we can get out of it," he said. "I think we are being pretty conservative and cautious."

The municipal energy association also disputed HEAL Utah's study conclusions, asserting the findings were flawed.

Utah cities that are members of Utah Associated Municipal Power Systems include St. George, Bountiful, Kaysville, Logan, Lehi, Brigham City, Heber City, Murray, Payson, Springville, Price and several others.