The United Illuminating Company (UI), based in Orange, Connecticut, was officially established in 1899, when the New Haven Electric Company acquired the Bridgeport Electric Light Company, expanding the company to a regional utility.
As Connecticut became an important manufacturing center in the early 1900s, UI flourished and spread its franchise outward to New Haven's and Bridgeport's outlying towns. Ultimately, its service territory encompassed 17 towns along the Connecticut shoreline.
For many years UI exclusively owned and operated the electric generation, transmission and distribution facilities in the greater New Haven and Bridgeport areas. As a result of Connecticut's 1998 deregulation legislation, UI was required to sell its electricity generation plants, including the facilities at New Haven and Bridgeport harbors, and to divest from other generation projects including the Connecticut Yankee and Millstone nuclear power plants.
In 2000, UI became a subsidiary of UIL Holdings Corporation, a New Haven-based corporation.
In 2015, UIL Holdings merged with the U.S. holdings of Iberdrola, S.A. to form AVANGRID, Inc. (NYSE: AGR), a diversified sustainable energy and utility company based in Orange, Connecticut, with operations in nationwide, from Portland, Maine to Portland, Oregon.
UI is proud to be part of the AVANGRID family of companies and shares its commitment to providing clean energy and reliable delivery to customers through innovative technology and sound investment in infrastructure.