The following explanation was published to Facebook yesterday by Janie Mitcham, former Sr. VP ERCOT Supply at Reliant Energy. It is the clearest explanation by an industry expert that I have come across for that happened to the power grid during Winter Storm Uri. I’ve incorporated some of her clarifying statements in the comments section into the body of the post. I’m publishing it here for easier dissemination, hoping to provide a whole lot of hurting and bewildered people with at least some of the clarity they have been without during this disastrous weather event. You can compare this with all the other information out there.
I keep getting questions about what happened in ERCOT so I’ve done some digging. Here’s what I know. ERCOT issued a 2020/2021 Winter Assessment in November 2020. It considers a range of normal and extreme conditions to assess the adequacy of generation. The assessment expected 83,000 MW of capacity to be available, only 963 MW of which was wind and solar (it was not the wind). Wind is seasonal and already had low projections in the plan because of the time of year. Normal peak load was projected at 57,699 MW and the previous extreme peak load had ben 65,915 MW over only ONE HOUR in Jan of 2018. Of the expected 83,000 MW of generation an extreme scenario assumed that 23,462 would be unavailable due to both historic and extreme outage conditions. That would still leave 59,538 MW available, 8,216 MW less that needed for extreme conditions. An extreme load situation would need to be managed by rolling blackouts.
It is fact is that over 35,000 of gas/coal/nuclear generation went down to do freeze related issues. Natural gas supplies froze, plant equipment froze, the STP nuclear plant tripped due to a freezing issues. STP is very reliable and has only had two trips in recent history – one in 2016 and one in 2013. (I’m guessing that the STP Unit 1 trip on Monday at 5:37pm on Tuesday was the single most destabilizing event and the closest we came to total grid failure). If you think back many of you that had power at that time may have gone dark at that same moment as load had to come off quickly.
Corporate greed/deregulation caused this – not really. This exact same scenario played out in December 1989 when Texas was fully regulated. Texas power plants are not designed to handle sub-freezing temps that last for several days. Power plants in the north are designed differently and most turbine decks are enclosed. This costs a lot of money that shows up in the form of higher electric rates. Don’t expect to pay the same for a Kia and a Mercedes. Look up average electric rates by state. Maine pays 19 cents a kwh we pay 10 cents. (Be careful, comparisons are tricky, for example: states with hydro have very low rates). Texas has low rate for a non-hydro state. We also use a lot of power due to our air conditioning load. How much more a month would you pay for something that happens once every 30 years.
This weather was EXTREME. A State-wide event of sub-freezing weather for multiple days has only happened in 1989, 1951, 1940 and 1899. Could some winterization efforts have been done better – most definitely. Would it have avoided the problems we had – maybe not.
They had a week to prepare and blew it – not worth addressing. See above for long-term design issues.
Could new laws or better regulation fix this – yes, but at a cost. See above. No one wants to pay now for something that has no immediate payoff. Don’t get me started on building codes, etc.
Could ERCOT have done things better – I don’t know but I want to personally thank them for saving the grid. They are going to be vilified for something largely out of their control. Their only focus was to keep the entire grid from collapse and their only tool was to cut load. It is a law of physics that the load and the generation must balance. We came very close to a real disaster. I’m sure a hind sight review will find some mistakes but overall the end result probably would not have changed much.
Also, ERCOT doesn’t determine who loses power, the transmission companies do. ONCOR and CenterPoint control most of the state. There is no question that how the blackouts were handled needs full investigation. But I can’t emphasize how close we came to total grid failure. Keeping the grid stable HAD to be the number one priority. When a circuit that has been blacked out is turned back on there is a huge surge in power demand because everything comes on simultaneously. When the grid is in a fragile state that could be catastrophic. I’m sure CenterPoint and ONCOR had every intention of rolling the blackouts but felt the system was just too unstable – they didn’t just forget to.
Transmission companies are also frantically working to keep critical infrastructure on than rather than “choosing” who to black out. Hospitals, water supply, etc. all take priority over residential. CenterPoint didn’t forsake you. Many experienced, knowledgeable people were doing the best they could in an emergency situation. In hindsight we can always show that things could have been done better but trust me, when you are in the battle you are fully engaged and doing the best you can.
If you noticed, many people got power back on only at night. That’s because all the lighting load turned off, businesses closed for the day, etc. and gave the system some breathing room. If everyone who had power had limited use to their heat and one light, way fewer people would have been blacked out. I believe that technology could be better used to address the blackouts.If everyone had power for six hours then off for six hours they wouldn’t be so upset right now. We do have better technology that was not available in 1989 in the form of smart meters that I don’t think are fully utilized and they could be a long-term solution to managing the blackouts better.
Communication was terrible – people deserve to have timely, factual information in an emergency. Communication was a total, inexcusable failure.
Would connecting to a national grid instead of being isolated have helped – I don’t think so. While we were focused on what was happening to us, grids across the nation were in rolling blackouts. You can only import power when someone else has excess and no one did. Texas is interconnected with both MISO and SPP through DC ties. Both of their systems were also having blackouts.
To be clear, I am not giving ERCOT, the generators, transmissions companies, gas pipelines, gas producers, or anyone else involved a pass on what just happened. A full investigation needs to take place and if previous recommendations were ignored someone should be held accountable. I just want to put the magnitude of what happened into perspective and stress that once events unfolded, keeping the grid from going down was the only thing that mattered at that moment in time.
I hope this helps and I hope everyone is safe and warm.