Transmission Alternatives Study
In accordance with ISO New England planning procedures, the Maine Power Reliability Program (MPRP), has evaluated a range of possible transmission solutions to address the reliability needs of the transmission system and has selected a Preferred Transmission Alternative for further evaluation.
Additionally, MPRP is conducting a study of potential Non-Transmission Alternatives, such as energy conservation and efficiency programs, as possible substitutes for, or to delay building new transmission lines.
CMP Transmission Needs Assessment
In 2006 Central Maine Power Company (CMP) began the Maine Power Reliability Program (MPRP) to study Maine's bulk power system along with the Independent System Operator-New England (ISO-NE). CMP's bulk power transmission system, completed between 1969 and 1971, is almost 40-years old. It now serves twice as many customers with double the electric demand. The results [read study summary here], included in ISO-NE's 2007 Regional System Plan [read system plan here], concluded that Maine has insufficient transmission to meet mandatory reliability criteria and to ensure reliable service for Maine's electric customers. The inadequacies, if not addressed, will cause service blackouts. ISO-NE concluded that additional 345 kV and 115 kV transmission lines are needed to solve the reliability problems identified in the needs assessment report.
Transmission Projects Solve the Identified Need
ISO-NE, CMP, and the MPRP Study Group conducted technical evaluations to assess how the possible combinations of transmission projects would perform during normal, peak and possible outage scenarios and how those options would support future flexibility over 20,000 performance scenarios were evaluated. The study identified fifteen (15) sets of transmission projects, in various combinations, as possible solutions.
CMP Selects the Best Performing Transmission Solution
CMP has selected a preferred transmission alternative based on a number of factors, including electrical performance, cost effectiveness, impacts to landowners and Maine's environment and robustness under various forecasts of future conditions. The main component of this set of transmission projects, referred to as the N5/S1 Alternative, is a new 345 kilovolt (kV) line from Orrington Maine (15 miles south of Bangor) via existing transmission corridors (generally located along a line to Detroit-Windsor-Lewiston-Yarmouth-Gorham) to Portsmouth New Hampshire, but they also include upgrades to substations and improvements to the region's 115 kV electric system.
Next Steps
CMP will complete a study of alternatives to transmission system solutions, including energy conservation, energy efficiency, Demand Side Management (DSM), distributed and local generation. The transmission and non-transmission solutions will be presented at regional and state forums.
CMP expects to request ISO-NE approval of the preferred transmission alternative in the spring of 2008 and to begin the state approval process for its preferred solution thereafter.
MPRP Proposed Solution
