“Right now, a lot of the communities are looking at it for climate reasons,” said Ursula Schryver, director of education and customer programs at the American Public Power Association. “The biggest benefit about public power is the local control.”

But private utilities often resist giving up control — and customers — to new, public competitors, arguing that it leaves them unable to recoup investments made in anticipation of customer needs. In addition, the power industry cites its experience and long history in keeping the lights on while meeting environmental goals.

“This is our business. It’s what we do,” said David Eves, chief executive of the Public Service Company of Colorado, the division of Xcel Energy operating in Boulder. And because its parent company operates in eight states, he added, the utility can focus on being more efficient. “We don’t run other parts of the city operation and deal with those kinds of things. It’s our specialty.”

Roughly 70 percent of the nation’s homes are powered through private, investor-owned utilities, which are allowed to earn a set profit on their investments, normally through the rates they charge customers. But government-owned utilities, most of them formed 50 to 100 years ago, are nonprofit entities that do not answer to shareholders. They have access to tax-exempt financing for their projects, they do not pay federal income tax and they tend to pay their executives salaries that are on par with government levels, rather than higher corporate rates.

That financial structure can help municipal utilities supply cheaper electricity. According to data from the federal Energy Information Administration, municipal utilities over all offer cheaper residential electricity than private ones — not including electric cooperatives, federal utilities or power marketers — a difference that holds true in 32 of the 48 states where both exist. In addition, they can plow more of their revenue back into maintenance and prevention, which can result in more reliable service and faster restorations after power failures.