NSTAR (Massachusetts) has officially flipped the switch on its massive underground transmission project, easing congestion in the regional power grid and adding much-needed capacity to the existing system. The 18-mile high-voltage transmission line is one of the largest electric infrastructure upgrades in the history of the United States utility industry. It will help ensure the region can meet steadily growing energy demand in time for the all-important summer peak.

“This project is truly an engineering and construction marvel that benefits customers all over New England by increasing the efficiency and reliability of the regional power grid,” said Thomas J. May, NSTAR chairman, president and CEO. “The importance of upgrading and expanding our critical infrastructure cannot be overstated. While our goal is to help customers use energy as efficiently as possible, we also know that electricity demand continues to grow and the transmission system must be able to meet this need.”

The new 345,000-V (345 kV) line will allow NSTAR to tap into electricity resources in Southeastern Massachusetts and Rhode Island. Because the regional electric grid operates like a highway system, the new line will help ease bottlenecks that can often drive up the cost of power for consumers. The project is a key component in a series of improvements needed because customers’ demand for electricity is projected to exceed available capacity in coming years.

Construction on the $220 million project began in the spring of 2005. NSTAR developed extensive traffic-control plans to minimize the impact of the construction on local families and businesses. In addition, a multi-faceted communications plan helped to keep all interested parties informed of the project’s scope and progress.

“We want to thank all of our customers and neighbors as well as state and local officials for their cooperation and patience during the construction of this very important project,” May added.

The transmission project route begins at a new NSTAR switching station in the town of Stoughton and runs one 345 kV line to Hyde Park and a second 345 kV line to South Boston. The Hyde Park line was energized in October of 2006.