Entergy Louisiana on Jan. 6 filed with the Louisiana Public Service Commission a report on the deactivation later this year of Ninemile Unit 3 and Willow Glen Units 2 and 4, and the retirement last year of Little Gypsy Unit 1.
The commission has previously considered the potential economic benefits associated with the deactivation or reduced usage of older gas- and oil-fired units (called the “legacy units”) on the Entergy System.
Entergy in recent years has sought to construct new combined cycle gas turbine (CCGT) resources. As a result of a 2009 request for proposals (RFP), the company developed and placed into service in late 2014 in the DSG sub-region the 561-MW Ninemile Unit 6 (NM6) CCGT facility. Similarly, based on the results of the 2014 Amite South RFP, the company is currently seeking authority from the commission to install an additional 923-MW CCGT facility (the St. Charles Power Station) at the Little Gypsy site on the edge of the DSG sub-region.
Entergy Service Inc. (ESI) is also currently conducting, on Entergy Louisiana’s behalf, the 2015 RFP for Long-Term Developmental and Existing Capacity and Energy Resources, though which the company seeks up to 1,000 MW of long-term capacity, energy, and related products from Developmental Resources to be located in the Louisiana portion of the West Of The Atchafalaya Basin (WOTAB) planning region and/or existing resources (to be located within the MISO South footprint), with service beginning on or before June 1, 2020. The company has reserved the right to select more or less than the targeted amount of capacity, and this RFP will include the market-test of a CCGT self-build alternative that would be constructed at Entergy Louisiana’s Nelson site in Westlake, Louisiana (near Lake Charles) within WOTAB.
The report noted that Willow Glen Units 2 and 4 (WG2&4) are currently operational. However, sustaining safe and reliable operations at WG2&4 would require, among other things, the inspection, refurbishment, or replacement of various components, including turbine valve, boiler feed pump and auxiliary equipment. The units are: Unit 2, 179 MW (ICAP capacity), 51 years old; and Unit 4, 483 MW (ICAP), 42 years old. The two units were approved in August 2015 by the Entergy Operating Committee for deactivation on June 1 of this year, after which point they would officially be considered to be mothballed.
The report said: “On December 22, 2015, MISO approved the Attachment Y Notice for WG2&4, finding that the deactivation of Willow Glen Units 2 and 4 would not result in violations of applicable reliability criteria and without conditioning such approval on any transmission upgrades.”
Little Gypsy 1 was retired in 2015 due to age, need for costly repairs
Little Gypsy Unit 1 (LG1) was approved by the Operating Committee for retirement as of June 1, 2015. This is a 228-MW (ICAP) unit that is 54 years old. The report said: “The LG1 unit entered a Forced Outage (‘FO’) on April 12, 2014 after coast down vibration increased to 10-12 mils. General Electric (‘’GE’), the OEM of the turbine, assessed the unit and asserted the possibility of a crack in the HP turbine rotor based on conditions observed and GE’s experience with similar units. Following the FO event, the unit exhibited issues with start-up vibration. The OEM recommended that the unit not be operated due to the potential safety concerns associated with a possible rotor crack. Inspection and repairs were deferred pending analysis of the economic viability of restoring the unit to operating condition.”
Among the negatives weighing against an LG1 restart is that if LG1 is returned to service after April 2017, it is highly likely a U.S. Environmental Protection Agency new source review (NSR) would be triggered and installation of selective catalytic reduction (SCR) equipment for NOX control would be required, costing approximately $40 million.
In 2014, the Operating Committee approved deactivation of Ninemile Unit 3 (NM3) as of June 1 of this year. This is a 103-MW (ICAP) facility that is 60 years old.
The report said: “The NM3 unit entered commercial operation over 60 years ago in 1955. Over the 2005 to 2012 period, the NM3 unit took on an increasingly critical role, as six generating units supporting the DSG planning regions 115-kV network assumed non-operational statuses (Michoud Unit 1, Paterson Units 3, 4 and 5, and Ninemile Units 1 and 2). As a result, only NM3 and Michoud Unit 2 remained in service as DSG Reliability-Must-Run (‘RMR’) support for the Company’s 115-kV network. NM3 continued to represent a critical asset in DSG planning region, and was expected to continue in that operating mode until the Commission-approved NM6 CCGT unit achieved commercial operation. The expected (and eventual) configuration of the NM6 CCGT would interconnect that unit’s two CTs to the 115-kV network, with its steam turbine connected to the 230-kV network. The installation of these two new CTs on the 115-kV network was expected to supplant much of the energy requirements from NM3 and alleviate the need to rely on NM3 as a DSG RMR unit.”
The report added: “Today, NM3 is 60 years old and is typically operated on a seasonal basis. Conventional gas-fired boiler-steam turbine/generators have a typical design life of 35-40 years, but with maintenance and selective capital investments, the operating life of such units can be sustained beyond 40 years when economic to do so. At 60 years old, however, extending the service life of the NM3 unit would require major component replacements and an anticipated investment of tens of millions of dollars to comprehensively address the known unit conditions discussed above, plus additional and potentially significant investments to address the unknown conditions that would almost certainly be discovered if a major repair were undertaken.”
In October 2014, MISO approved the Attachment Y Notice for NM3 based on the planned completion of certain previously identified transmission reinforcements.
This Jan. 6 report opened a docket to review these unit shutdown plans. There is a Feb. 9 deadline for intervention requests in the docket, with the first such request filed on Jan. 20 by the Louisiana Energy Users Group.