FERC on Oct. 17 approved NERC reliability standard TPL-001-4, which establishes transmission planning performance requirements to protect the bulk electric system (BES) from a broad range of system conditions and probable contingencies.
The approval resolves the outstanding issue over footnote 12 (formerly footnote “b”), which applies to non-consequential load loss and was the foremost element holding up FERC’s approval. It also addressed the directives of Orders 693 and 762, as well as the notice of proposed rulemaking FERC issued in April 2012.
NERC on Feb. 28 proposed its most recent revision to the reliability standard, TPL-001-4 (Version 4), seeking to address FERC’s concerns, which date back to 2010, that NERC’s standards did not adequately clarify or define circumstances under which an entity could use planned non-consequential load loss as a mitigation plan to meet performance requirements for single contingency events; did not provide assurances that the process would be effective in determining when it was appropriate to plan for non-consequential load loss; and did not contain NERC-defined criteria on circumstances to determine when an exception for planned non-consequential load loss was permissible. Specifically, footnote 12 allowed for transmission planners to plan for non-consequential load loss after a single contingency event without adequate safeguards, and undermined the potential benefits the standard could provide.
Between 2011 and 2013, NERC proposed several iterations of the reliability standard, TPL-002-1 (Version 1), TPL-002-2 (Version 2) and TPL-001-4 (Version 4), which includes eight requirements, R1-R8, and Table 1, which lists seven contingency planning events that require steady-state and stability analysis as well as five extreme event contingencies.
“The commission finds that Reliability Standard TPL-001-4 introduces significant revisions and improvements to the TPL Reliability Standards, including increased specificity of data required for modeling conditions, and requires annual assessments addressing near-term and long-term planning horizons for steady state, short circuit and stability conditions,” FERC said in the final order.
The reliability standard includes a provision that allows a transmission planner to plan for non-consequential load loss following a single contingency by providing “a blend of specific quantitative and qualitative parameters for the use of planned non-consequential load loss” to address BES performance issues, FERC said. Such performance issues include firm limitations on the maximum amount of load that an entity may plan to shed; safeguards to ensure against inconsistent results and arbitrary determinations that allow for the planned non-consequential load loss; and a more specifically defined, open and transparent, verifiable, and enforceable stakeholder process.
Though it approved the standard, FERC directed NERC to modify the standard to address the concern that it could exclude planned maintenance outages of significant facilities from future planning assessments.
In a supplemental NOPR that FERC issued in May, the commission had proposed to approve TPL-001-4 (Version 4), saying that though the standard differed from its directives, it adequately addressed the underlying reliability concerns raised in FERC Orders 693 and 762, as well as the April NOPR. Footnote 12 would improve reliability “by providing a blend of specific quantitative and qualitative parameters for the permissible use of planned non-consequential load loss to address bulk electric system performance issues,” the commission said.
In the supplemental NOPR, FERC said the stakeholder process appeared to be adequately defined and included specific criteria and guidelines that a responsible entity must follow before it may use planned non-consequential load loss to meet Reliability Standard TPL-001-4 performance requirements for a single contingency event.
“We approve Reliability Standard, TPL-001-4 with footnote 12 because it satisfies the concerns raised in the supplemental NOPR,” FERC said. “Footnote 12 provides a blend of specific quantitative and qualitative parameters for the permissible use of planned non-consequential load loss to address bulk electric system performance issues, including firm limitations on the maximum amount of load that an entity may plan to shed, safeguards to ensure against inconsistent results and arbitrary determinations that allow for the planned non-consequential load loss, and a more specifically defined, open and transparent, verifiable, and enforceable stakeholder process. Use of planned non-consequential load loss should be rare and must be used consistent with the process established here.”
FERC Commissioner Cheryl LaFleur released a statement, saying the commission’s approval of NERC’s proposal puts “one of the most difficult outstanding issues dating from the commission’s March 2010 reliability orders” behind them.
FERC has required NERC to submit a report based on the first two years of the new standard’s implementation. The regulations are effective 60 days after publication in the Federal Register.
TPL-001-4 (Version 4) footnote 12 states: An objective of the planning process is to minimize the likelihood and magnitude of Non-Consequential Load Loss following planning events. In limited circumstances, Non-Consequential Load Loss may be needed throughout the planning horizon to ensure that BES performance requirements are met. However, when Non-Consequential Load Loss is utilized under footnote 12 within the Near-Term Transmission Planning Horizon to address BES performance requirements, such interruption is limited to circumstances where the Non-Consequential Load Loss meets the conditions shown in Attachment 1. In no case can the planned Non- Consequential Load Loss under footnote 12 exceed 75 MW for US registered entities. The amount of planned Non-Consequential Load Loss for a non-US Registered Entity should be implemented in a manner that is consistent with, or under the direction of, the applicable governmental authority or its agency in the non-US jurisdiction.