Building a high-capacity electricity line linking northern and central Maine would seem to be a win for both regions and the state as a whole. The 345-kilovolt line connection proposed by Maine Public Service and Central Maine Power, to run from Chester in northern Penobscot County to Detroit in southeastern Somerset County, would improve electricity reliability for The County and allow the region to export its burgeoning wind-generated electricity.

But in the era of deregulated electricity, it’s not entirely clear whether this needed infrastructure upgrade will be a financial burden or a boon for Maine businesses and residents.

First, some facts to remember: Utilities such as MPS and CMP are in the transmission business and no longer generate electricity. That change came with deregulation. And Maine’s transmission network is part of the ISO New England, a management entity that exists, in theory, to ensure that all six states have access to the least expensive power available.

Any skepticism about the new connection – which still is being studied – does not reflect on the utilities. MPS and CMP are responding to a clear problem: the lack of connectivity between Aroostook County and the heart of Maine’s and New England’s electric grid. That problem was identified by the Maine Public Utilities Commission in 2006, when just one supply offer was made to users in The County.

But problems may come when the cost of building the new transmission line is apportioned. If ISO New England approves of the project, as seems likely, given that the line could carry 800 megawatts of new electricity from wind power projects south to the heart of the grid, the cost would be distributed among the six states. But Maine’s Legislature is considering three options, suggested by the PUC, to change its deal with ISO New England. One option would have it renegotiate its deal with ISO. The other options are for Maine to go it alone or to form a new entity with New Brunswick.

The PUC’s report to the Legislature in January identified concerns about the MPS-CMP project and other proposed transmission upgrades.

“There is no overarching and comprehensive process to ensure that the transmission actually needed by the region is developed,” the report cautions. “Although ISO-NE is intended to serve this function to some extent … the status quo is not equipped to yield solutions that are least cost, efficient, equitable, or promote state and regional policy and environmental goals.”

It might seem fair that ratepayers in high-demand southwestern Connecticut pick up some of the cost of the new lines in Maine – which could total $400 million to $500 million for the entire Limestone to Detroit corridor. But the PUC report suggests that under this model, the real cost of electricity for Connecticut users may be masked, which could lead them “to prefer to import power … even when it is uneconomic to do so.” This, in turn, could lead to too much money being spent on transmission upgrades.The MPS-CMP proposal should lend urgency to the Legislature’s consideration of the future of Maine’s place in the New England grid. Maine’s potential for generating new electricity is great, and that card must be played in a way that gives Maine business and residential users the best deal possible.