More conservative reserve calculations, quicker and more granular demand response and optimizing trades with neighboring regions: These are some of the changes PJM is considering in the wake of September’s unexpected heat wave, officials told the Members Committee webinar yesterday.
PJM gave a detailed presentation on the events of Sept. 9-11, when PJM was forced to shed load during unseasonably high temperatures at a time when large numbers of transmission and generation resources were out of service for planned maintenance.
The September events added urgency to concerns that arose after the heat wave of mid-July (see Focus on AEP Transformer, Prices in Heat Wave Review) as well as adding some new ones.
Yesterday’s briefing lasted about two hours, and the lessons learned will likely consume many more hours of stakeholder meetings.
Seeking a Nimbler DR
Stu Bresler, PJM vice president of market operations, told the committee that the September episode illustrated the need to give operators the ability to make quicker and more targeted use of demand response.
The Capacity Senior Task Force, which is meeting today, is considering reducing DR’s minimum lead and run times. Also under discussion will be changes to rules limiting operators’ ability to target DR calls geographically.
Almost 6,000 MW of demand response was dispatched on Sept. 11 — an all-time record that underscored its increasing importance to the RTO. “We’re going to have to get used to DR as an operational tool being used outside of the June-July-August period,” Bresler said.
Conservative Reserve Estimates
The CSTF isn’t the only stakeholder group that will be discussing the fallout from the heat spike. The Operating Committee will be discussing improving generator data to more accurately calculate reserve quantities after a poor synchronized reserve response led to an unusually long spinning event Sept. 10.
Adam Keech, director of wholesale market operations, said operators will likely be using “more conservative” RTO reserve calculations in the future.
The newly-formed Energy Market Uplift Senior Task Force will be discussing changes to rules allowing emergency DR to set prices, as it did in some areas during both the July and September events.
Officials are having second thoughts about the price cap on demand response — now effectively $1,800 per MWh but scheduled to increase to $2,700. “Are we comfortable with $2,700?” asked PJM’s Becky Carroll.
In addition, PJM may seek to create a product to reduce interchange volatility along its seam with MISO similar to the Coordinated Transaction Scheduling product with NYISO. Members will vote on CTS Thursday (see MRC/MC Preview).
Load Sheds Hit 44,000
In addition to the presentation, PJM yesterday also released a 21-page report providing officials’ preliminary analysis of the events of Sept. 9-11.
PJM cut power to 44,000 customers in southern Michigan, northern Ohio and northwest Pennsylvania Sept. 9 and 10 as temperatures unexpectedly hit the mid-90s and the RTO found itself without enough transmission or generation.
Although the cuts were relatively small — the 154 MW in total load shed was less than 0.1% of Sept. 10’s peak load — the situation could have been far worse.
When a 345/138 kV transformer in AEP’s South Canton area tripped Sept. 9, four 345 kV lines were lost, leading PJM operators to fear it could worsen to a cascading outage.
There were also concerns of a widespread blackout Sept. 10, when a 345 kV line near Erie, Pa., was lost. PJM ordered FirstEnergy to drop 70 MW of load at 17:41. When that did not alleviate concerns, PJM ordered the cut of an additional 35 MW.
Conditions were exacerbated by weather forecasts that missed peak temperatures by up to 5 degrees — leading PJM to under-forecast loads. Balancing congestion, which results when day-ahead loads differ from real-time, totaled $23.1 million in the ATSI zone over Sept. 10 and 11.
The Cavalry Fails to Arrive
One major concern was the failure of generating resources to provide Tier 1 synchronized reserves as loads steadily climbed on Sept. 10. When PJM called a spinning event at 15:48, it showed reserves of about 2,000 MW. Yet only 130 MW of additional generation responded within 10 minutes, leading PJM to call on 800 MW from NPCC as the RTO’s area control error (ACE) fell to a deficit of 1,600 MW.
At the peak, synchronized reserve response totaled only 350 MW. The spinning event lasted an unusually long 68 minutes. “The [synchronized reserve] response clearly was not there,” said PJM’s Chris Pilong.
As a result, Pilong said, operators felt they had to dispatch demand response for support the following day. PJM called on a record of almost 6,000 MW of demand response in the AEP, ATSI, Dominion and Duquesne zones on Sept. 11. “The operators didn’t have a lot of confidence in the numbers reported” as reserves, he said.
Operators also declared a Transmission Loading Relief 5 on Sept. 11, cutting 100 MW of firm transactions on the Neptune DC tie to New York.
Next Steps
Officials said they will produce a “Frequently Asked Questions” document in response to members’ inquiries, as they did after the July event. Stu Bresler, Adam Keech, and Dave Anders will be receiving queries.
For More Information: Initial Analysis of Operational Events during the September 2013 Heat Wave
