SAWG 10/29/21 - CIMView

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SAWG 10/29/21

Table of Contents

Executive Summary

At today’s SAWG ERCOT decided that it will ask the PUC if it should do the 2022 Reserve Margin study (expecting PUC to say no), presented on how they are going to try to include distributed generation in future capacity (CDR) reports (they are, they weren’t before), gave a nice presentation of the probabilistic system adequacy (SARA) report, and talked about how effective they think weatherization efforts will be (contact if you have thoughts on the assumptions they will use).



  • ERCOT talked about how they are planning on putting distributed generation into the CDR report.
    • Double counting/undercounting is hard
    • Need to recognize ERS participation of DG
    • Sample report here
    • Draft NPRR here
  • Discussion about the wisdom of doing the Astrape/Brattle Reserve margin (MERM/EORM) study that is typically done every other year.
    • Costly ~$280k
    • Similar study currently being done as part of market redesign effort
    • General consensus is that it would be duplicative waste of money, but better ask the PUC just to be sure.
  • ERCOT presented the probabilistic winter Supply Adequacy report (SARA
    • Take it with a grain of salt, seems to assume weatherization not effective
    • The presentation starts with a good rundown of what the probabilistic SARA is and the method they used to generate it, so if you are planning on actually using it in your business, I would definitely take a look at that.
    • One fiend texted me during the presentation that the SARA is ERCOT’s “Farmer’s Almanac”
  • ERCOT presented analysis on how effective post 2011 Winter Storm weatherization was (about 50% reduction in forced outages for similar days)
  • ERCOT presented a plan for how they intend to model Uri related weatherization effectiveness in future capacity studies.
    • Leaning toward 50% conservative and 80% optimistic scenarios
    • Contact if you would like to comment on those assumptions

Discussed Issues

  • CDR
  • DG
  • SARA
  • Weatherization