Filed with the New York State Public Service Commission on Dec. 17 was a Dec. 11 letter from the New York ISO to National Grid about the possible shutdowns of the Dunkirk and Huntley coal plants.
Said the New York ISO letter: “By letter dated October 30, 2015, National Grid informed the New York Public Service Commission that reliability of the local National Grid transmission system and the Bulk Power System can be maintained through at least 2020 even if Dunkirk is mothballed and Huntley is retired effective March 1, 2016, subject to the implementation of certain system upgrades. In order for the NYISO to make a final determination regarding whether a need exists for Huntley Generating Units 67 and/or 68 to be retained as Reliability Must Run (RMR) generator(s), the NYISO requests certain confirmations from National Grid that are described below.
“In the event that both Huntley and Dunkirk are out of service, the NYISO has verified that all applicable NERC, NPCC and NYSRC reliability criteria for the New York State Bulk Power System can be maintained once certain relay setting modifications at the Sawyer 23kV distribution station are implemented.
“The NYISO requests that National Grid please state via a written response to this letter whether or not: (a) all applicable NERC, NPCC and NYSRC reliability criteria for the non-bulk National Grid system will similarly be maintained when the relay setting modifications at the Sawyer 23kV distribution station are implemented, and (b) whether National Grid will make the relay setting modifications at the Sawyer 23kV distribution station by March 1, 2016.
“The NYISO requests that National Grid please state in a written response to this letter whether or not it has identified a need for Huntley Generating Units 67 and/or 68 to be retained as Reliability Must Run (RMR) generator(s) to meet any applicable local criteria.”
Also filed with the commission on Dec. 17 was a response letter from National Grid to the New York ISO, dated Dec. 16, that said: “I write in response to your December 11, 2015 letter to me regarding the effects on the transmission system of Niagara Mohawk Power Corporation d/b/a National Grid (‘National Grid’ or ‘the Company’) from the retirement of Huntley Units 67 and 68 effective March 1, 2016 proposed by Huntley Power LLC (‘Huntley’), and the mothballing of the remaining unit operating at Dunkirk Power LLC (‘Dunkirk’) plant by January 1, 2016.
“National Grid has evaluated its transmission system and has determined it is not necessary to retain the Huntley or Dunkirk plants in order to satisfy NERC, NPCC, or NYSRC reliability criteria, or the Company’s local transmission planning criteria.
“Your December 11 letter states the NYISO has verified that all applicable NERC, NPCC and NYSRC reliability criteria for the New York State Bulk Power System can be maintained once certain relay settings modifications are implemented at the Sawyer 23 kV distribution substation. National Grid is planning to implement certain relay settings modifications at its Sawyer 23 kV distribution substation, with a projected completion date of December 31, 2015. National Grid confirms that once these modifications are implemented, all NERC, NPCC and NYSRC reliability criteria applicable to National Grid’s non-bulk transmission system can be maintained without any of the Dunkirk or Huntley units in service. National Grid has evaluated its local transmission planning criteria and has determined that it is not necessary to retain the Huntley or Dunkirk plants in order to satisfy the Company’s local transmission planning criteria.
“In its October 30, 2015 letter to the New York Public Service Commission, National Grid committed that it would continue to evaluate system conditions and provide updates to the NYISO and Department of Public Service Staff regarding planned transmission projects. In the October 30 letter, National Grid indicated its intent to install two 230kV capacitor banks in the Huntley area along with potential reconfigurations and/or relay setting modifications at a 23kV distribution station to address voltage reliability issues primarily due to 23kV load connected to the 230kV system. Since that time, the Company has determined that applicable reliability criteria can be maintained with the relay setting modifications alone. Installation of the capacitor banks is recommended to maintain voltage levels and aid in service restoration under certain contingency conditions; however, the capacitor banks are not required to meet applicable reliability criteria.
“As indicated above, National Grid anticipates that the necessary relay setting modifications will be in place by December 31, 2015. Both capacitor banks are expected to be in service before June 1, 2016.”
NRG Energy (NYSE: NRG) said in its Nov. 4 Form 10-Q quarterly report that it has taken impairment losses related to plans it recently communicated to the New York State Public Service Commission to shut the coal-fired Huntley and Dunkirk power plants.
Huntley Units 67 and 68 are coal-fired units, with 218 MW of nameplate capacity apiece, that began operating in 1957 and 1958, respectively. The units are located in Tonawanda, N.Y., and are interconnected to the National Grid system in NYISO’s Zone A.
NRG’s Dunkirk Power owns and operates a coal-fired station in Dunkirk, New York, made up of a (nameplate) 100-MW Unit 1, a 100-MW Unit 2, a 217.6-MW Unit 3, and a 217.6-MW Unit 4.