During the Public Utility Commission’s meeting yesterday, commissioners received an update from ERCOT concerning grid performance and other metrics during the most recent winter weather event – Winter Storm Heather. Below is a HillCo report covering ERCOT’s presentation to the PUC.
Public Utility Commission
January 18, 2024
The Public Utility Commission met on January 18 to discuss: the most recent winter weather event, a number items on the docket, a reliability standard for the ERCOT market, resiliency plans, battery state of charge standards, among others. An archive of the meeting and the agenda can be found here.
This report is intended to give you an overview and highlight the various topics taken up. It is not a verbatim transcript of the discussions but is based upon what was audible or understandable to the observer.
Item 49: Discussion and possible action on electric reliability; electric market development; power- to-choose website; ERCOT oversight; transmission planning, construction, and cost recovery; and electric reliability standards and organizations arising under federal law.
- Jackson – Thanks to all our partners to everyone who worked to ensure grid reliability during this most recent winter weather event
- Reforms that have been put in place have kept our grid secure and functioning
- Event ended yesterday; will take several weeks to conduct a complete analysis
- Glotfelty and Cobos thank frontline workers and other personnel
- Cobos – Were some local outages, but statewide the grid stayed strong; weatherization put in a strong backbone for our grid
- Cobos – Firm fuel supply product, the first in the country, has shown tremendous benefits
Woody Rickerson, ERCOT
- Do not have all the information yet, will take a while to get all the information in
- Issued a number of advisories and warnings starting January 10
- The winter weather moved in on Sunday in the panhandle
- By noon today expect everywhere in the state to be above freezing
- New record peak was set on Sunday at 65k; Monday morning broke that record at 76k, broke record again on Monday night and broke again on Tuesday morning; 78,138k
- Wednesday had a high peak of 77k
- This was a significant storm; historically, only winter storms Elliot and Uri had a lower load weighted average
- Winter storm was longer than 2011, 2018, polar vortex, and Elliot
- This was the first winter full weatherization rule was in effect; 1.3k units had weatherization inspections
- Net load exceeded 68k three different times over the last week; first time was Monday morning, Tuesday morning, Tuesday evening; thermal units provided 78% of that energy
- 3k MW of incremental forced outages; totaling 7k, which is half of what we saw during Elliot
- Gas pipeline/gas supply; inspection restrictions 1.5k MW net loss
- Had issues in San Antonio – were 4 peaks – those issues were resolved
- Wind performance – fluctuated from 1.9k to 24k MW; Low wind was most concerning peak Monday morning and peak Tuesday afternoon
- Wind forced outages 7k MW on Monday; only 2.3k were due to icing; will have to pull an RFI to see what the others were about
- Solar performance – for the first time solar was at the level that changed the operating day; provided a significant amount in the middle of the day; allowed battery charging, allowed issues for thermals to be corrected
- Tuesday set a record of 14,837 MW of solar which was 23% of the load
- Significant difference in solar output between the days, some days was 7k
- Forced outages for solar units was not significant at around 300 MW
- Batteries over peak provided about 1.5% total energy needed at that peak; about 1.2k MW
- Average state of charge from 14-17 was about 65% for the fleet; maximum was 76% which was 55 MWh; minimum state of charge was 41% on Tuesday after the evening peak
- Peak discharge was 1,280 MW on Tuesday morning; peak charge 1,148 MW; as expected
- On Monday system peaked at 400, Tuesday morning and Tuesday evening at 1100; peaks responded with highest net load
- Tuesday 1900 day ahead versus 560; Tuesday evening day ahead 300 and real time was higher
- Are coming from a place where we under forecasted peak load, like during Elliot and other winter storms due to industrial demand respond and LFL price responses
- Are looking for better ways to calculate demand response prices; are starting to incorporate information that is helping ERCOT tune their models
- Other things have impact of accuracy of load forecasting like combined effect of conservation calls, holiday schedules, school/offices closures/delays
- Can forecast versus actual load, and the put weather back into the model; will begin to see the effects all of these things had
- Obvious conservation call had a big effect; people did conserve
- Actual weather versus weather forecast; we will improve in this area as well, but will always be weather variance in the forecast
- Glotfelty – Pleased with thermal fleet performances, were a lot of outages in the summer, they were ready for this and were the backbone of the system
- Glotfelty – Encourage ERCOT to keep working on load forecasting; doing a good job but can always do better
- Glotfelty – Have any freeze offs in the gas supply?
- Not aware of any well head issues
- Cobos – How many firm fuel resources were deployed?
- Around 1.2k to 1.3k MW
- Jackson – In comparison to previous storms, the temperatures were colder and length of time?
- Longer than most, this storm, Heather, is longest we had except for Uri
- Jackson – Storm was a good test of the reforms in place; talked to generators in panhandle who held their own, but had high wind later in the event
- Jackson – Need to think about continued diligence – in terms of the gird continuing to perform
- Jackson – Heard good feedback from generation, transmission, gas supply, pipelines, etc. issues were identified early and had a successful outcome