ORRINGTON, Maine — Central Maine Power Co. wants to upgrade its power grid, something it hasn’t done in 38 years, and the U.S. Army Corps is reviewing the permit application and inviting the public to comment.

The proposed $1.5 billion upgrade would double the capacity of the electric grid’s approximately 500-mile backbone between Orrington and Eliot, where it connects to Newington, N.H.

The project would add a new 345-kilovolt transmission line stretching across 13 counties and 78 cities and towns, and almost all of the new construction — approximately 98 percent — would be adjacent to the current power grid, if approved.

“To compensate for the project’s projected unavoidable impacts to waterways and wetlands, the applicant is currently proposing wetland and upland habitat restoration, enhancement, and preservation measures on a total of 3,349 acres at 12 locations throughout the project corridor,” the Army Corps Web site states.

“The applicant also proposes $1,548,092 [in] contributions to the Maine Natural Resource Mitigation Fund … and has included approximately 1,420 acres of preservation in the Kennebec River Gorge in the compensation plan,” it states.

If approved, five new substations would be built and eight existing facilities would be see upgrades. Three other substations would be decommissioned.

The proposed project would take approximately four years to construct and would employ on average 2,100 construction workers.

The Army Corps Web site states the CMP project would affect essential fish habitat for Atlantic salmon, but added that “the Corps has made a preliminary determination that the site-specific adverse effect will be minimal.”

Public comments, which must include the reference number NAE-2008-03017, can be sent by mail or e-mail and must be submitted by Nov. 20. Mail letters to: U.S. Army Corps of Engineers, New England District, Maine Project Office (ATTN: Jay Clement), 675 Western Ave., No. 3, Manchester 04351, or by e-mail to: jay.l.clement@usace.army.mil.

Those who would like more information about the CMP project may call Jay Clement, permit project manager, at 623-8367.