MISO wants to know how it can improve frequency response under an evolving generation fleet and is asking for stakeholder involvement to draft an issues statement.

“This isn’t a new topic. The industry has been grappling with the issue for years,” said Durgesh Manjure, MISO’s manager of resource adequacy coordination.

Manjure said MISO hasn’t encountered the frequency response challenges that other systems such as ERCOT have encountered.

“But that doesn’t mean everything is fine and we won’t have to introduce something to keep this reliable trajectory going forward,” Manjure said during an Aug. 10 meeting of the Reliability Subcommittee (RSC). “By no means is this an issue now or next year, but I can’t say that with the same level of confidence for five years out.”

The RTO said that “opportunities exist to improve dynamic models” and performance measurement.

MISO said its changing fleet is driving the frequency response discussion, with coal taking an ever-shrinking share, while gas and wind sources climb. Manjure said MISO relies on coal for “most if not all” of its frequency response, but technological advancements are allowing other generation types to provide a governor-like response to a drop in frequency.

Between 2009 and 2015, MISO’s coal generation capacity dropped from 71.8 GW to 65.2 GW, while wind capacity almost doubled from 7.6 GW to 15 GW. Natural gas, responsible for only 6% of MISO energy production in 2010, now claims 28%; coal’s share fell from 73% to 45% over the same period.

According to NERC’s State of Reliability 2016 report, frequency response reliability in the Eastern Interconnection is expected to decline from the approximate 2,500 MW/0.1 Hz in 2012 to a little more than 2,000 MW/0.1 Hz in 2019.

Manjure said MISO wants to know if its models accurately reflect actual systemwide performance and what fuel mix point would render MISO’s frequency response inadequate. MISO is also asking if it needs to improve its tools that measure frequency response and revise Tariff or market mechanisms relating to frequency response.

“This is very high-level, very open to feedback,” Manjure said.

Manjure asked for stakeholder input that will be used to shape an issues statement in the coming weeks.

Improvement to Pseudo-Ties Process on MISO Horizon

Kyle Abell of MISO’s market planning division said MISO is trying to improve the congestion management process for its increased volume of pseudo-ties.

MISO said it has experienced escalating pseudo-tied generation with load farther from the seams in 2016. In the 2015/16 planning year, MISO-based generation pseudo-tied into PJM equaled only 155 MW; in the 2016/17 planning year, the amount is expected to reach about 2,000 MW. In the 2017/18 planning year, pseudo-ties are expected to creep toward 2,800 MW, with many of the deeper pseudo-ties sent to attaining balancing authorities with “very limited or no modeling-based visibility” of how their usage affects the larger MISO system.

Abell said MISO is contemplating new requirements for approving a pseudo-tie, including notification, pre-assessment and conditional approval steps. In addition, the RTO may set out requirements for an attaining balancing authority’s network model for proposed pseudo-ties. Currently, MISO reviews and approves pseudo-tie requests, while balancing authorities are responsible for market-to-market redispatch.

MISO asked stakeholders for suggestions to improve its pseudo-tie congestion management before Aug. 26. The RTO also said it would meet with neighboring balancing authorities and RTOs and its Independent Market Monitor to discuss the issue. Abell said he would make another pseudo-tie presentation at the Aug. 16 Planning Subcommittee meeting.

MISO plans to revise its processes around congestion caused by pseudo-ties through November, in time to draft a work plan to implement the changes in December.

Smooth Operations in MISO Despite ‘All-Time Hottest’ July

MISO operations performed well in July despite several hot weather and severe weather alerts, said Steve Swan, MISO senior manager of dispatch and balance.

Swan said July 2016 was the “all-time hottest July” for multiple cities in the southern portion of the MISO footprint. It was also the driest month since MISO’s creation for some southern MISO locations. Load peaked at 120.6 GW on July 21.

MISO reported that July 10, 12 and 20 fell outside of its unit commitment performance targets since forecasted load didn’t materialize due to thunderstorm activity; units that were preemptively called up had to stay online to fulfill their minimum run times. MISO also had one maximum generation event in July.

July also marked the first month MISO was required to abide by NERC’s balancing authority area control error limit (BAL-001-2) standards, which limit interconnection frequency errors to less than 30 minutes. Swan said MISO did not experience an error lasting longer than 15 minutes event in July.

RSC Chair Tony Jankowski commended MISO for its operations in the face of the hot weather. “We’ve had a pretty good summer so far, and MISO’s gotten us through some hot weather we haven’t seen in a while,” Jankowski said.

Winter is Coming and Coordinated Seasonal Assessment is Scoped

With Labor Day looming, MISO is already thinking about winter. Its 2016/17 winter Coordinated Seasonal Assessment, which assesses risks and system capabilities will include four main analyses, said MISO’s Katie Hulet:

• A steady-state AC analysis to study the effect of simple and complex contingencies;
• An analysis identifying large phase angle differences associated with reclosing a transmission line;
• A voltage stability analysis that will assess four critical interfaces for high transfers in combination with transmission and generator outages, which can cause stability issues; and
• A first contingent incremental transfer capability analysis to study the impact of high megawatt transfers and flowgate limitations. This analysis will examine six transfers in addition to wind transfer sensitivity.

MISO also will use only approved retirements and planned and forced transmission and generation outages lasting two months or more between December and February in its assessment.

Hulet said MISO would return to the RSC in November to provide the study’s results.

— Amanda Durish Cook