Texas needs better planning and execution from ERCOT.
Texas has a serious problem: not enough electricity when we really need it. While a lot needs to be fixed, three issues need immediate attention.
The Electric Reliability Council of Texas is responsible for managing the flow of electric power to meet about 90% of the state’s electricity demand. During the recent severe winter weather event, ERCOT planning and execution issues proved problematic.
Let’s first examine two planning problems.
The first deals with ERCOT naiveté. According to ERCOT, the Texas grid has a little more than 100,000 megawatts of “installed” capacity, of which about 28% is made up of intermittent renewable sources — wind and solar. ERCOT’s baseload capacity comes from coal and natural gas, together making up 67% of installed capacity, and nuclear, which is about 5%. ERCOT includes a significant portion of each of these sources when calculating what’s called the reserve margin, or the amount of capacity that exceeds demand.
In early November 2020, ERCOT issued its Seasonal Assessment of Resource Adequacy report for this winter. “ERCOT anticipates there will be sufficient installed generating capacity available to serve system wide forecast peak demand this winter season, December 2020-February 2021,” ERCOT said. The assessment estimated that “nearly 83,000 megawatts of resource capacity is expected to be available for the winter peak,” well in excess of the “57,699 megawatts” forecast for peak demand.
Then came the arctic cold.
As temperatures began to plummet across Texas on Sunday, Feb. 14, ERCOT projected that demand would peak at about 74,000 MW, significantly higher than originally forecast. As night approached, wind turbines began to freeze, some thermal plants tripped offline due to the extreme cold, and natural gas production and delivery were constrained, causing additional thermal plants to fail.
By 1 a.m. Monday, Feb. 15, coal and natural gas-fired generation were supplying 79% and 77% of their installed capacity, respectively, while wind was supplying 21% of its installed capacity. By Monday night, those numbers had dropped. Coal and natural gas-fired generation were supplying 59% and 56% of their installed capacity, while wind was supplying only 3% of its installed capacity.
It is a serious planning mistake to include renewable sources when estimating how much power — actual generation — will be available at times of peak demand. When a thermal generator is unable to meet its obligation to serve demand, the generator must pay a penalty. Renewable resources have no such obligation. If the wind is not blowing or the sun is not shining, these generators have no obligation and pay no penalty. That has to change.
An independent third party should be retained to conduct a thorough investigation of exactly what was happening in the ERCOT control room before and after 1:50 a.m. on that Monday and if the operators had full understanding of the operational risks that generators face when frequency changes that fast. If the investigation concludes the ERCOT operators had the appropriate knowledge and performed as they should have, this question will be resolved. However, if such an investigation finds mistakes caused thermal generation to automatically trip offline due to the frequency event, then significant changes should be made in ERCOT operational protocols.
In sum, three big issues — two dealing with planning and a third dealing with real-time execution — need to be addressed and fixed. Failure to do so is not an option.
Phil Wilson is the general manager of the Lower Colorado River Authority. He wrote this column for The Dallas Morning News.
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