U.S. Energy Information Administration - EIA - Independent Statistics and Analysis
Today in Energy
Republished January 22, 2015, 2:45 p.m. to correct an error in the text.
Northern Maine is a unique power market: unlike any other part of the Lower 48 states, this region is connected to one of the three main power grids serving the United States and Canada only via transmission lines that run through Canada. Currently, grid operators are considering transmission options to give northern Maine direct links to the rest of New England in an effort to enhance reliability and expand access to electricity markets.
The transmission grid in northern Maine, which includes the transmission systems of Maine Public Service Company and Eastern Maine Electric Cooperative, is operated by the Northern Maine Independent System Administrator (NMISA). NMISA is a small electricity region serving 54,000 customers with a peak load of 135 megawatts (MW).
NMISA links to the rest of New England through connections with the Canadian utility New Brunswick Power Corporation. Various proposals over the past decade have sought to build transmission to directly connect NMISA to ISO New England (ISO-NE), which operates the rest of the transmission grid and wholesale electricity markets in New England. Such a connection may address reliability concerns, provide access to ISO-NE's markets for northern Maine's generators, and enhance retail competition.
Traditionally, NMISA had more generating capacity than it needed and exported power to New Brunswick. In recent years, however, lower natural gas prices allowed natural gas-fired generators in New Brunswick to compete with (and often underbid) generators in NMISA, leading to the retirement of some generating units located in NMISA and concerns about reliability. NMISA subsequently entered into reliability must-run contracts with generators that had already shut down or were planning to do so. An investigation by the Maine Public Utilities Commission (MPUC) into Northern Maine's reliability concerns that began in late 2012 (and is still ongoing) generated various proposals. These proposals include building new transmission facilities to connect with ISO-NE, adding new generation capacity, adding demand response, and reinforcing transmission connections with New Brunswick.
Other proposals include some wind farm developers that are building generators within NMISA's footprint and establishing their own transmission lines directly into ISO-NE. These developers are seeking to benefit from the area's favorable wind resources and the need for reducing carbon emissions under the Regional Greenhouse Gas Initiative (RGGI). It is not yet certain whether any of this generation will be able to serve load within NMISA. For example, First Wind built its own 38-mile 115-kV transmission line that began operating in 2009 to connect the 83-megawatt (MW) Stetson Wind projects to ISO-NE. The Stetson Wind farm is physically located within NMISA's footprint, but it is connected to ISO-NE, not to NMISA.
More generating capacity is coming to the area: a 148-MW wind project (Oakfield) is under construction, and a 250 MW project (Number Nine Wind Farm) has been proposed. Both wind farms have contracts with New England utilities for the power and renewable energy certificates, and both developers plan to pay for their own transmission line connections to ISO-NE (each more than 50 miles). Under a recent agreement, it is possible that the Number Nine Wind Farm transmission tie will also connect NMISA to ISO-NE.
Additionally, in anticipation of an expected request for proposals from the New England States Committee on Electricity (NESCOE), there are at least three potential projects to build high-voltage direct-current (HVDC) lines from northern Maine to Massachusetts.
- The Maine Green Line would transmit up to 2,800 MW of renewable energy—including onshore wind from northern Maine and imports of hydropower from eastern Canada to New England.
- Loring Energy has proposed using a 200-mile corridor, initially used as a jet fuel pipeline to the former Loring Air Force Base, to construct the land-based portion of a land/sea HVDC line to Boston.
- The Northeast Energy Link is a proposed 230-mile 1,100-MW HVDC line delivering renewable energy from northern and eastern Maine and eastern Canada into southern New England, using existing transportation corridors in eastern Maine, New Hampshire, and Massachusetts.
Principal contributor: Lori Aniti