NYISO: Two localized transmission security needs will require remedial action in near term

The New York ISO (NYISO) said on Oct. 18 that according to its “2016 Reliability Needs Assessment,” (RNA), while the state’s bulk power system has adequate power generation resources to meet reliability needs for the next decade, two localized transmission security needs will require remedial action in the near term.

As noted in the document, the RNA assesses the transmission and resource adequacy, as well as the transmission security, of the New York Control Area (NYCA) bulk power transmission system from 2017 through 2026 (referred to as the study period).

The NYISO said in its statement that while no resource adequacy needs were identified on the bulk power system, the RNA identified two localized transmission security reliability needs that would begin in 2017, absent remedial action by transmission owners:

  • The New York State Electric & Gas (NYSEG) Oakdale 345/115-kV transformer
  • The Long Island Power Authority (LIPA) East Garden City to Valley Stream 138-kV line

According to the RNA, following NYISO Board of Directors approval of the RNA report, the NYISO initiates the next step, which begins by requesting local transmission owner plans (LTPs) updates. As part of that step, the NYISO will consider updates to local transmission owner plans and, if necessary, solicit market-based solutions, regulated backstop solutions, and alternative regulated solutions to the identified reliability needs. The RNA also noted that the NYISO then proceeds to assess the viability and sufficiency of each of the possible solutions, leading to the development of the comprehensive reliability plan (CRP).

Discussing the transmission and resource adequacy results, the RNA said that from the transmission and resource adequacy perspective, the NYCA is within the loss of load expectation (LOLE) criterion (one day in 10 years, or 0.1 events per year) throughout the 10-year study period, and that is mainly attributable to the decrease in the summer peak baseline load forecast of about 2,300 MW in 2021, as compared with the 2014 RNA.

When recent and planned capacity deactivations were included in the calculation, the net statewide surplus increased by about 3,000 MW as compared with the 2014 RNA and about 975 MW as compared with the 2014 CRP, the RNA said.

Speaking of the transmission security results, the RNA noted that in Long Island, the East Garden City to Valley Stream 138-kV line could not be secured within applicable thermal ratings when another 138-kV line is out of service – also known as an N-1-1 condition. The power flow on that facility is driven by the combination of LIPA load in western Long Island and the scheduled 300 MW wheel between Con Edison and LIPA. That overload has now been identified as a result of no longer reducing the wheel following an outage, for which Con Edison’s contractual portion of “Y50” is assumed to be delivered to Con Edison, thus reducing the portion of western Long Island load that is capable of being served through the overloaded facility from generating sources in eastern Long Island, the RNA added.

The Oakdale 345/115-kV transformer also could not be secured within applicable thermal ratings under certain transmission line outage conditions, the RNA said, noting that that overload was noted in the 2014 RNA as well. At that time, NYSEG provided an update to its local transmission owner plans that included a third Oakdale transformer and reconfiguration of the Oakdale 345-kV substation. NYSEG’s planned in-service date was 2018, which met the inclusion rules and therefore address the reliability need identified in the 2014 RNA. However, the RNA added, as part of the 2016 “Gold Book” reporting process, NYSEG updated the in-service date to winter 2021, which does not meet the inclusion rules for the 2016 RNA base case. Without that project in the base case, the Oakdale transformer remains overloaded.

Those two transmission security related reliability needs will be eligible for the NYISO to solicit solutions if those reliability needs remain unresolved by further udpates to local transmission owner plans, the RNA added. Following such a solicitation, developers may submit market-based solutions and alternative regulated solutions for evaluation as part of the 2016 CRP, the RNA said.

Given the limited time between the identification of the transmission security related reliability needs in the RNA report and their occurrence in 2017, the use of demand response and operating procedures, including load shedding under emergency conditions, may be necessary to maintain reliability during peak load periods until permanent solutions can be put in place, the RNA said.

Accordingly, the responsible transmission owners will present any updates to their LTPs that impact the reliability needs identified in the 2016 RNA, including their proposed operating procedures pending completion of their permanent solutions, for review and acceptance by the NYISO and consideration for inclusion in the 2016 CRP.

The RNA also said that as demonstrated in the 2016 RNA scenarios, a higher load level or additional retirement of capacity could cause resource adequacy reliability needs. Several scenarios were evaluated as part of the RNA, including the “High Load (Econometric) Forecast – Resource Adequacy,” which excludes the energy efficiency program impacts and retail solar PV programs from the baseline peak forecast, resulting in a 2,962 MW increase in peak load in 2026, as compared with the RNA base case forecast of the same year.

In another scenario, “Western New York Public Policy Transmission Need – Transmission Security,” a transmission project has been completed in response to the Western New York Public Policy Transmission Need, whose objective is to relieve congestion in western New York, including access to increased output from the Niagara hydroelectric facility and additional imports of renewable energy from Ontario, the RNA said.

The analysis finds that a transmission project that addresses the Western New York Public Policy Transmission Need, once in service, would reinforce the western New York system reliability beyond the currently assumed local transmission owner plans, and would resolve the Oakdale 345/115-kV transformer overload, the RNA said.

Among other things, the RNA said that the NYISO also analyzed the risks associated with the cumulative impact of environmental laws and regulations, which may affect the flexibility in plant operation and may make fossil plants energy-limited resources.

About Corina Rivera-Linares 3054 Articles
Corina Rivera-Linares, chief editor for TransmissionHub, has covered the U.S. power industry for the past 15 years. Before joining TransmissionHub, Corina covered renewable energy and environmental issues, as well as transmission, generation, regulation, legislation and ISO/RTO matters at SNL Financial. She has also covered such topics as health, politics, and education for weekly newspapers and national magazines. She can be reached at clinares@endeavorb2b.com.