Braintree plans 66-MW addition to Watson plant; retirement of an existing unit

ISO New England and Braintree Electric Light Department (BELD) on Sept. 28 filed with the Federal Energy Regulatory Commission a newly executed non-conforming Standard Large Generator Interconnection Agreement between the ISO and BELD as both interconnection customer and interconnecting transmission owner, covering a 66-MW, gas-fired addition to an existing power plant.

The parties also filed a notice of cancellation of the existing Large Generator Interconnection Agreement between them that covered the existing plant. BELD is a vertically integrated entity, using generation, transmission and distribution assets that it owns to serve its approximately 16,000 customers (meters) within its 14 square mile service area in the Town of Braintree, Massachusetts.

BELD experienced a system peak demand of 93.5 MW in August 2006. BELD owns and operates Watson Units 1 and 2 (each of which is a 58-MW generator powered by a Rolls Royce Trent 60 combustion turbine) which entered commercial operation in 2009, and Potter 2 generating station, a 96-MW, dual-fuel, combined cycle facility which entered commercial operation in 1975.

This new interconnection deal covers BELD’s expanded Thomas A. Watson Generating Station, which will be rated at 182 MW gross and 180.5 MW net, and will be comprised of three simple cycle combustion turbine units located at Potter Road in Braintree, Mass. Two of the simple cycle combustion turbine units (Watson Units 1 and 2) that are each rated at 58 MW gross are existing facilities that were interconnected pursuant to a 2008 Interconnection Agreement.

Under an Interconnection Request dated Feb. 24, 2014, BELD will be increasing the output of the existing facility by adding a new simple cycle combustion turbine rated at 66 MW gross (Watson Unit 3). Watson Unit 3 will be interconnecting to the transmission system at BELD’s Potter Switchyard via existing facilities that are currently being used by BELD’s Potter 2 facility, which BELD will be retiring in time to allow for the connection of the new Watson Unit 3.

The targeted commercial operation date for the new Watson Unit 3 is May 22, 2019.

A project contact is: William G. Bottiggi, General Manager, Braintree Electric Light Department, 150 Potter Road, Braintree, MA 02184, Tel: (781) 348-1010, Fax: (781) 348-1003,

About Barry Cassell 20414 Articles
Barry Cassell is Chief Analyst for GenerationHub covering coal and emission controls issues, projects and policy. He has covered the coal and power generation industry for more than 24 years, beginning in November 2011 at GenerationHub and prior to that as editor of SNL Energy’s Coal Report. He was formerly with Coal Outlook for 15 years as the publication’s editor and contributing writer, and prior to that he was editor of Coal & Synfuels Technology and associate editor of The Energy Report. He has a bachelor’s degree from Central Michigan University.