The company expected to be the first in the United States to operate a small nuclear reactor is facing setbacks that have caused supporters to question whether the novel technology will ever realize its potential as a tool to combat climate change. //

Utah Associated Municipal Power Systems, a group of small community-owned utilities in six Western states, cited a rise in expected costs for the NuScale reactors. The group is counting on the nuclear power to provide around-the-clock, zero-carbon electricity to replace a coal plant it plans to close, but its members say they won’t need the new cleaner electricity source until later than expected.

“The setbacks are not fatal,” said Erik Olson, a climate and energy analyst at the Breakthrough Institute. “But if this project falls through, that would be an enormous blow to the promised next wave of nuclear power.”