LS Power unit pursues two 50-MW gas turbines for Connecticut power plant

Wallingford Energy II LLC (WE II) has petitioned the Connecticut Siting Council for a Declaratory Ruling approving WE II’s proposal to install and operate two additional generating units of approximately 50 MW each at an existing generating facility owned and operated by an affiliate, Wallingford Energy LLC, in Wallingford, Conn.

The project is being proposed primarily to help satisfy capacity and fast-start operating reserve needs in Connecticut and New England, noted the Aug. 28 application. The project is eligible for approval by declaratory ruling because it is a generating facility that will be located at a site where a generating facility existed prior to July 1, 2004, the application noted. Further, due to its location, configuration, emissions profile reductions, and expected limited operation as a peaking facility, the project will not have substantial adverse environmental effects.

WE II proposes to add two General Electric-made combustion turbines (CTs) and appurtenant equipment to the existing Wallingford Energy Facility. The two additional CTs, referred to as Units 6 and 7, will provide quick-start capacity in the Southwest Connecticut zone, a transmission-congested load pocket within the ISO New England electrical system. Units 6 and 7 will be able to achieve full load output within 10 minutes of being dispatched by ISO New England.

“The ‘quick-start’ nature of this peaking capacity is vital to the reliable operation of the power system by enabling it to recover from system contingencies, such as a sudden loss of generating capacity or transmission lines outages or unexpected swings in intermittent renewable generation,” said the application. “Units 6 and 7 will be highly efficient LM6000 aeroderivative engines equipped with selective catalytic reduction (SCR) systems and oxidation catalysts.”

Wallingford Energy II is a member of the LS Power Group, which has developed, constructed, managed or acquired more than 32,000 MW of competitive power generation. Headquartered in East Brunswick, New Jersey, LS Power Group owns and operates a diverse portfolio of power generating facilities throughout the United States. WE II is a New England Power Pool (NEPOOL) member.

The existing facility owned by Wallingford Energy consists of five General Electric LM6000 natural gas-fired combustion turbine units and associated equipment, with a total output of approximately 219 MW during summer conditions. Major equipment now at the facility includes: a turbine exhaust system for each combustion turbine with selective catalytic reduction systems and oxidation catalysts; three natural gas compressors; one approximately 410,000 gallon demineralized water storage tank; one 20,000 gallon aqueous ammonia storage tank; three generator step-up transformers; a generator switchgear/breaker unit for each combustion turbine generator; a natural gas-fired anti-icing boiler rated at 33.5 million British thermal units per hour (MMBtu/hr); a 600-kW emergency black start generator and dedicated 500 gallon fuel oil tank; water and ammonia injection and auxiliary skids; a sound wall; and plant operations building.

This facility is electrically connected via two existing 115kV gen-tie lines to the adjacent Wallingford 13M substation owned by the Wallingford Department of Public Utilities. Fuel for the facility’s combustion turbines is supplied by an existing 12-inch diameter natural gas pipeline lateral connected to 10-inch and 16-inch pipelines of the Algonquin Gas Transmission Co. system.

The two new CTs will share the facility’s electrical and gas interconnections, as well as much of the facility’s equipment. The facility originally entered service in 2001 on the former site of the Alfred L. Pierce Station, an approximately 22.5 MW coal-fired steam facility dating from 1953 that was later converted to oil-firing.

Company says fast-start turbines can provide brief-duration run times

The application noted: “As fast start turbines, Units 6 and 7 can be offline while providing 10 and 30 minute reserves in the ISO-NE market, rather than continuously operating at low load to be able to respond timely to increased demand or system contingencies. Unlike traditional steam units in Connecticut that must operate at their economic minimum output to provide emergency reserves, Units 6 and 7 will only be called on based on economic merit or when needed to resolve contingencies and to maintain system reliability. As a result, Units 6 and 7 can provide valuable operating reserve services without producing air emissions, while more efficient but less responsive units are meeting system energy requirements. Being more efficient than many of the oil-fired steam units currently in operation in Connecticut, Units 6 and 7 require less fuel per unit of energy produced and are highly flexible in responding to the needs of the system. Both of these characteristics help to moderate wholesale electricity prices.”

An air permit application has been submitted to the Connecticut Department of Energy and Environmental Protection which includes a 4,000 hour per year operational limit for each proposed CT. This limitation is anticipated to be included as a condition of the final issued air permit.

WE II proposes to install a new generator step-up transformer (GSU) which, in combination with or independent from an open terminal on an existing facility GSU, will be used to step up the voltage of the output from Units 6 and 7 to 115 kV for transmission on the bulk electrical system. A new gentie line will connect the project’s new GSU to the existing Wallingford 13M ring bus at the existing breaker position that is to be used for Units 3-7 once the project is complete.

Once all necessary pre-construction permits are received, WE II said plans to manage a third-party contractor for the construction of the project. The contractor will be responsible for obtaining ordinary course construction permits, procuring materials and equipment, subcontracting as warranted and managing day-to-day construction activities. Major development and construction activities and anticipated completion dates are as follows:

  • Major State, Local and Federal Permit Applications Filed – August 2015
  • Issue Contractor Notice to Proceed – June 2016
  • Combustion Turbines Delivered – June 2017
  • Begin Startup and Testing – December 2017
  • Commercial Operations Date – April 2018
  • Start of Capacity Commitment Period – June 1, 2018

ISO-NE estimates that peak load will grow in excess of 1% annually in each of: the Southwest Connecticut subarea (in which Wallingford is located), the Connecticut zone, and New England as a whole, the application said. This load growth, combined with a concentration of recently announced retirements and the limited volume of new resources results in ISO-NE forecasting that the system will reach a resource shortage of more than 400 MW in 2019, growing in excess of 1 GW by 2022. The resource shortage could become further exacerbated if additional resources were to retire or fewer resources were imported from neighboring regions. WE II proposes the project as an efficient means to help satisfy the growing peak needs in the region while recognizing the limited forecasted annual energy usage growth.

A project contact is: Wallingford Energy II LLC, Attn: Blake Wheatley, 400 Chesterfield Center, Suite 110, St. Louis, MO 63017, Telephone: (636) 532-2200, Facsimile: (636) 532-2250.

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.