LEWISTON — It is not easy to make sense of the swirl of numbers surrounding the proposed $1 billion electrical transmission line from the Quebec border to Lewiston.

Take, for instance, a  pro-project mailer sent by Avangrid-owned Central Maine Power that features a construction worker in a hard hat with a power line behind him.

Across the top of the mailer, sent out over the winter, it says “New England Clean Energy Connect’s plan to support 3,500 Maine jobs.”

At the lower left is a box that boldly says “Yes! To 3,500 Maine Jobs.”

What makes it especially interesting is the power company mailed out a new version in recent days with the same picture that makes one big change: The 3,500 jobs became 1,600 jobs.

It is possible to defend both numbers given CMP says at the peak of construction, it will have 3,500 workers on the project, but will only need 1,600 on average during the construction period.

Assuming those estimates are accurate, both mailers are true.

But when two company mailers appearing within months of each other offer such wildly different job totals, it is no wonder Mainers are puzzled about the claims and counterclaims over a 145-mile long project that appears to grow more controversial by the day.

Sandi Howard, director of Say No to NECEC, said Monday the mailers are merely the latest example of CMP’s “ever-changing propaganda” that shows why Mainers cannot trust the company.

Thorn Dickinson, vice president of business development for Avangrid, said Monday the different numbers on the two mailers are “easily understood by anyone familiar with this project and Maine’s approval process.”

“One refers to the average number of jobs supported each year over the six years of development,” he said, “and the higher number is the expectation during the peak year of construction.”

Calling both mailers accurate, Dickinson said the numbers used on both “have been consistent since the onset of the project,” and have been confirmed by two independent economic analyses.

The controversial project, called New England Clean Energy Connect, aims to deliver a huge amount of hydropower-generated electricity from Quebec to Massachusetts. It would flow into the New England power grid from Lewiston to help replace the output from coal and nuclear plants that have been shuttered or will soon close.

It is a project pushed by Massachusetts that would be funded by ratepayers in the Bay State. The company says Maine would benefit from additional jobs; taxes; a few ancillary goodies, such as new fiber optic opportunities for rural broadband expansion; weatherization help; and a more-reliable regional power grid.

Opponents point to the environmental damage of widening existing transmission corridors and creating a 53-mile line in Somerset County, between the upper Kennebec River and the Quebec border. They also question claims that Spanish-owned Central Maine Power makes in favor of the project.

For Lewiston, which would house the most-costly portions of the project near the existing Larrabee Road substation, the project would mean an additional $8.4 million in annual property taxes, according to an estimate by the Maine Center for Business and Economic Research in Lewiston.

The utility claims “Maine communities that host the project will receive an estimated $18 million in increased property tax revenues each year, with the largest share going to western Maine communities in Androscoggin, Franklin, and Somerset counties,” which includes the money Lewiston would receive each year.

Howard said CMP’s tax revenue projections might bear little relation to reality.

She said the utility has a history of “overpromising tax benefits,” and pointed to several municipalities whose tax revenues fell short after CMP’s Maine Power Reliability Program, which began a decade ago.

Howard cited the figures for three towns she said showed CMP had made promises it did not keep.

In Dixmont, for example, Howard said the power company had estimated a new project earlier in the decade would be worth $24 million. It is now listed on the tax rolls at $4.3 million.

The power company responded it does not set the final distribution of costs among the towns along a route. That is done by the state, and it generally comes out about as expected.

In Lewiston, CMP claimed in a 2012 press release its new substation would cost $58 million. It is now pegged by the city at $51.2 million.

“The value and tax dollars generated appear to support what CMP estimated they would be,” Lewiston’s chief assessor, William Healey, said Monday.

On the other hand, officials in Caratunk told the Public Utility Commission the assessor found CMP “overinflates the proposed valuations in their presentations and that the lines are never assessed that high for tax purposes.”

The changing numbers, questionable tax benefits and well-known billing mistakes, Howard said, have helped undermine the company’s credibility.

“Why should we believe anything CMP says right now?” Howard said.

The company said Mainers should take a look at the facts.

Dickinson called Howard’s criticism “just another attempt by out-of-state project opponents to confuse the facts.”

“It’s part of the playbook that belongs to out-of-state interests: A concerted attempt to spread misinformation and to convince Mainers to kill the most-important clean energy project in our state’s history,” Dickinson said.

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