Middletown-Norwalk Transmission Project


Underground Construction

Edited by Joanne Ray

Over the years, growing consumer demand for electricity had created a bottleneck to the electric system in southwest Connecticut that became a threat to electric reliability. After years of research and planning, the Middletown-Norwalk Transmission Project was approved to bring the state's electric transmission system up to current standards.

In July 2004, Northeast Utilities contracted the Kansas City-based engineering firm of Burns & McDonnell as program manager for its $1.04-billion project. Burns & McDonnell soon embarked on a complicated and highly coordinated effort to upgrade and extend transmission and energy services across 18 communities.

Today, the Middletown-Norwalk Transmission Project involves construction of nearly 70 miles of new overhead and underground 345-kilovolt transmission line. There are 45 linear miles of overhead construction including the installation of more than 750 new steel monopoles that range from 80 to 185 feet tall. The remaining 24 miles of the route, through more densely developed areas, is being installed underground in either 4-foot-wide concrete duct banks or in one of multiple under-river horizontal directionally drilled tunnels. The project also includes five new or upgraded switching stations.

Burns & McDonnell is responsible for permitting, design, procurement, construction management, right-of-way acquisition, environmental issues, community relations, and document control.

The project is among the largest transmission capital projects ever constructed and is the first project to include a program management role in the power delivery industry. It will use more 345-kilovolt cross-linked polyethylene (XLPE) underground conductor cable than has previously been installed on any other single project in the country.

Since beginning construction in mid 2006, the project has made tremendous progress. Northeast Utilities and the Burns & McDonnell program management team are optimistic that the project will finish well ahead of schedule, closer to early 2009 than the original completion date of the end of 2009. The project will help to safely, responsibly and cost-effectively bring the state's electric transmission system up to current reliability standards.

Throughout the project the Burns & McDonnell program management team has done a good job of effectively controlling scheduling and costs. The project was Burns & McDonnell's first major effort in the Connecticut region, enabling them to open a New England office in Wallingford, CT.