Maine Power Reliability Program

(from Maine Townsman, March 2008)
Sara Burns, President and CEO of Central Maine Power Co.

On August 14, 2003, large portions of the Midwest and Northeast United States and Ontario, Canada experienced an electric power blackout, affecting 51 million people and lasting 4 days in some parts of the United States.  Outage related financial losses were estimated between $4 billion and $10 billion (US) in the commercial and industrial sectors.  The cause of the blackout, which originated in Ohio, was tied to weaknesses in the transmission system that were not properly assessed and understood by the utility owners or the system operator.

Partly in response to this massive system failure, Congress enacted the Energy Policy Act of 2005, requiring among other things the development of mandatory and enforceable electric reliability standards.  Until recently, the nation’s electric system relied on voluntary compliance.  The Federal Energy Regulatory Commission has designated NERC (North American Electric Reliability Corporation) as the official reliability organization for the United States.  NERC has the legal authority to enforce reliability standards on all owners and operators of the bulk power system.

NERC will be investigating the recent outage in Florida on February 26, 2008 that affected a large part of that state. The massive blackout was linked to an equipment failure in an electrical substation,  which triggered a cascading effect that resulted in  eight power plants shutting down or going off-line

Central Maine Power (CMP), as the owner of the bulk power transmission system that serves 560,000 Maine customers, is committed to ensuring compliance with NERC’s reliability standards AND avoiding the economic and personal disruptions that would be caused by a system failure in Maine.

In response to these challenges and to the growing demand for electric power, CMP launched the Maine Power Reliability Program (MPRP) in Decemeber 2006 to assess the reliability needs of Maine’s bulk power transmission system, evaluate solutions to ensure continued reliability of our system and to make the essential investments in our system to meet the needs of our customers into the next decade and beyond.

CMP  is working with ISO-New England, the operator of New England’s transmission grid to identify the system’s critical needs and develop solutions to meet those needs.    We began by developing 10 year forecasts for electricity demand and comparing them to our system capacity, using NERC’s national standards for grid reliability.

It should be noted that CMP’s transmission lines for moving bulk power went into service in 1971 and operates reliably today.   Much has changed in Maine in four decades.  Maine has grown and our electrical system must carry twice the power that it did in 1971.  Electricity demand now hits its peak in summer instead of winter.  Population growth and development have accelerated in many parts of the state.  All counties except Aroostook have grown in population since 1971.  Piscataquis County grew in population by 6%, but York County by 80% in that same period of time.  Sources of electricity are more varied and dispersed, and new renewable resources are emerging across the state. 

The MPRP needs assessment, which was completed in June of 2007, concluded that the Maine system does not have adequate transmission capacity to meet the newly adopted, mandatory reliability standards.  Within the next decade, the inadequacies could lead to service blackouts.

The study indicated that additional 345 kilovolt (345kV) and 115 kilovolt (115kV) power lines are needed in Central and Southern Maine and that several new 115kV lines are needed in Mid-Coast, Western and Downeast Maine to reliably serve our customers.  Also, additional autotransformers and related equipment are needed to support increased transmission capacity.

CMP evaluated a number of transmission alternatives that would address future system deficiencies, preferring the use of our existing rights-of-way for system improvements.  All the alternatives were carefully evaluated in terms of electrical performance, impact to abutting property owners, environmental protection and costs.  MPRP is considered a regional investment and will be paid by all the ratepayers in New England, not just those in Maine.  Up to 92% of the costs will be paid by ratepayers from the other five New England states

CMP has chosen a preferred route for further analysis depicted in a map shown at the end of this article.  The route passes through  more than 70 Maine municipalities over existing transmission corridors.   Municipal officials in all of those municipalities have been briefed on this preferred route and once CMP has made a final decision as to the route for the system improvements, more briefings will be conducted.  Most municipalities will have permitting jurisdiction over the improvements as will other federal and state regulatory agencies, including the Maine Public Utilities Commission (MPUC) and the Department of Environmental Protection.

The preferred route calls for the construction of an additional 345kV transmission line following existing transmission corridors from Orrington to the Maine-New Hampshire interconnect in Eliot (Orrington-Detroit-Benton-Windsor-Lewiston-Gorham-Eliot-Newington, NH).  CMP is also planning to build several new 115kV lines and upgrade others on existing corridors.

Separately, CMP has also commissioned a study of non-transmission alternatives such as energy conservation and efficiency programs as possible substitutes for, or to delay building new transmission lines. 

When the transmission and non-transmission studies are completed this spring, CMP will carefully weigh the results and submit a petition for a Certificate of Public Convenience and Necessity to the MPUC and also apply for the required state and local permits.

This reliability project will likely be the largest development project in CMP’s history, with estimates of $1 billion or more.  The MPRP will ensure a safe and secure supply of power; enhance system reliability; improve power quality; and improve operating efficiency.  In short, with the Maine Power Reliability Program, CMP is building the infrastructure to deliver reliable electric power for Maine’s future.

For more information about MPRP, please visit the Maine Power Reliability Program website at