UI Completes Transmission Line Rebuild Project to Strengthen Electric Grid

Learn more about the transmission line rebuild in Shelton, Derby, and Ansonia and its impact on the community in this video

ORANGE, Conn. - March 10, 2026 - United Illuminating (UI), a subsidiary of Avangrid, Inc., announced today the completion of the Derby Junction Ansonia Transmission Line Rebuild Project. This project involved rebuilding the existing transmission lines within the 4.1-mile corridor between Derby Junction in Shelton, spanning the Housatonic River, and crossing portions of Derby and Ansonia, ending at the existing Ansonia Substation. The steel lattice towers were replaced with single and double circuit monopoles, improving the reliability of the electric transmission system for customers in Connecticut and New England.

"It is critical that we continue to invest in our infrastructure and replace before the point of failure to ensure a strong and resilient grid that our customers can rely on," said Frank Reynolds, President and CEO of UI. "As storms intensify and energy demands grow, these upgrades are essential protections for the communities we serve. I am grateful for the work of our teams, and support of community partners, that allowed us to complete this project that will deliver benefits for decades to come."

The previous transmission line structures were originally built in the early 1920s. Over the years, the transmission lines have been upgraded several times in response to increasing demand for electricity. In 2012, UI began comprehensive engineering studies to assess the existing lines, and it was determined that they would need to be replaced to maintain safe and reliable power for customers.

This area is known as a load pocket, meaning that the loss of these transmission lines would result in loss of power to the substations that feed customers in Derby, Shelton, and Ansonia. Considering the critical facilities in the region, such as Griffin Health Hospital in Derby, the load pocket makes the transmission rebuild even more timely and essential.

"These structures were approximately 100 years old and among the oldest lines in our service territory," said Chuck Eves, Vice President of Electric Operations and Projects at UI. "When one part of the grid is vulnerable, it puts additional strain on the entire system. Rebuilding these lines now strengthens the backbone of our network, reduces the risk of future outages, and protects the critical facilities our communities rely on every day. This upgrade not only improves reliability and resiliency for customers in Derby, Shelton, and Ansonia, but also reinforces the stability of the broader transmission system across New England."

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About UI: The United Illuminating Company (UI) is a subsidiary of Avangrid, Inc. Established in 1899, UI operates approximately 3,600 miles of electric distribution lines and 138 miles of transmission lines. It serves approximately 341,000 customers in the greater New Haven and Bridgeport areas of Connecticut. UI received the Edison Electric Institute's Emergency Recovery Award in 2019 and 2021. For more information, visit https://www.uinet.com.

About Avangrid: Avangrid, Inc. is a leading energy company in the United States working to meet the growing demand for energy for homes and businesses across the nation through service, innovation, and continued investments by expanding grid infrastructure and energy generation projects. Avangrid has offices in Connecticut, New York, Massachusetts, Maine, and Oregon, including operations in 25 states with approximately $48 billion in assets, and has two primary lines of business: networks and power. Through its networks business, Avangrid owns and operates seven electric and natural gas utilities, serving more than 3.4 million customers in New York and New England. Through its power generation business, Avangrid owns and operates more than 80 energy generation facilities across the United States producing more than 10.5 GW of power for over 3.1 million customers. Avangrid employs approximately 8,000 people and has been recognized by JUST Capital as one of the JUST 100 companies - a ranking of America's best corporate citizens - in 2025 for the fifth consecutive year. The company was named among the World's Most Ethical Companies in 2025 for the seventh consecutive year by the Ethisphere Institute. Avangrid is a member of the group of companies controlled by Iberdrola, S.A. For more information, visit https://www.avangrid.com.

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