LEWISTON — The Public Utilities Commission on Tuesday rejected a Lewiston portion of Central Maine Power Co.’s proposed $1.4 billion power line upgrade.

The Lewiston Loop portion of the statewide expansion Maine Power Reliability Program would have built a new  substation near Middle Street and added lines connecting that to existing substations at Gulf Island and to in the southern part of the city.

PUC commissioners ruled that CMP’s plan didn’t thoroughly enough consider alternatives to the Lewiston upgrades, including lower voltage options to provide electricity without transmission lines. Options could have included generating electricity locally — solar, wind or river power — or reducing consumer electrical demand through conservation.

“CMP has not met its burden of proof in this case,” PUC Commission Chairman Jack Cashman said in a written statement. “The utility has not shown to my satisfaction through comprehensive testing or analysis that construction of the Lewiston Loop project is the most cost-effective means of addressing power reliability needs in the Lewiston area.”

Phil Nadeau, deputy city administrator, said he was concerned that the denial could hurt the utility’s ability to deliver electricity to Maine’s second-largest city.

“There is certainly necessity for the Lewiston loop,” Nadeau said. “We could be looking at a downtown casino and an entire riverfront development. All of that needs electricity, and that’s the one thing a city of our size should never have to worry about. In my mind, the state should bend over backwards to make sure Lewiston has what it needs to do the economic development and the job creation they want us to do.”

CMP spokesman John Carroll said he was waiting to get a written copy of the commission’s findings before discussing the company’s response.

“One thing they have talked about is needing more analysis,” Carroll said. “That would be the most logical place for us to start.”

CMP’s Maine Power Reliability Program calls for upgrading a swath of power lines, beginning in Eliot in southern Maine and passing through central Maine to Orrington, where the lines would connect to lines from Canada. Along they way, they pass through Litchfield, Monmouth, Leeds, Greene, Lewiston and a corner of Auburn at the Durham line.

In some places, lines would be rebuilt or replaced. In other places, lines would be added, including 115-kilovolt and 345-kilovolt lines. The 345-kV poles, not common in Maine, are wider than traditional power-line towers and can be 20 to 25 feet taller than the lower-voltage poles.

Commissioners approved the bulk of statewide program in June 2010, including a new Larrabee Road substation. They postponed a decision on the line expansions meant to go downtown.

The City Council approved a tax incentive in July 2009 to convince the utility to move some of its proposed lines around some residents’ homes. CMP agreed. Those changes added an estimated $3.5 million to the utility’s costs.

CMP was expected to pay an additional $1.2 million to Lewiston in new property taxes for the new substation and new power lines. The tax incentive agreement would have returned $358,723 of those new taxes to the utility each year.

staylor@sunjournal.com