PORTLAND, Maine — Central Maine Power Co. notified Maine regulators Thursday that it plans to work with Houston-based Spectra Energy on a plan to increase the capacity of two of the company’s natural gas pipelines.

CMP said in a joint filing with two Spectra pipeline subsidiaries that it will join the region’s largest electric utility, Northeast Utilities, in drafting the outline of an agreement that would use ratepayer subsidies from New England electricity customers to enter a long-term contract with Spectra to advance its Access Northeast expansion project.

The project also has interest from Eversource Energy in Connecticut, Massachusetts and New Hampshire, according to the filing Thursday.

CMP’s declaration comes as three pipeline companies have put forward competing expansion proposals that are seeking a long-term contract backed by Maine electricity ratepayers.

The omnibus energy bill passed in 2013 authorized the Maine Public Utilities Commission to have the state’s investor-owned electric utilities buy up to $75 million in natural gas capacity annually from a pipeline company, for up to 20 years.

The PUC is still evaluating proposals from the different companies, against power price forecasts it commissioned from various consulting groups.

In October, PUC staff determined that the cost of pipeline capacity would need to be very low for such an investment to pay off for electricity customers in Maine.

The report left open the possibility that any of the projects separately could have a worthwhile impact on reducing the cost of natural gas or electricity prices.

The investment from Maine and possibly ratepayers in other states would aim to reduce the difference in natural gas prices between New England and the rest of the country, a difference exacerbated in the winter because heating and power generation demand strains the region’s natural gas pipeline capacity.

That, in turn, affects power prices as most of the region’s electricity is generated using natural gas.

Spectra has said its plan would increase capacity on its Algonquin and Maritimes & Northeast pipelines, which connect with more than 70 percent of the region’s power generators. The project solicited expressions of interest in capacity on that expansion through May 1.

CMP previously said that it would be willing to enter such a long-term contract. Its filing Thursday made known that it prefers to enter such a contract with Spectra.

While Maine is considering spending that ratepayer money, a regional group of energy policymakers are working on a plan to have ratepayers across New England collectively support such long-term gas capacity deals.

Darren Fishell

Darren is a Portland-based reporter for the Bangor Daily News writing about the Maine economy and business. He's interested in putting economic data in context and finding the stories behind the numbers.