About the Project
We welcome any feedback or suggestions; contact the authors at firstname.lastname@example.org. Stay tuned for future CES research on Texas electricity on this page.
ERCOT Froze in February 2021. What Happened? Why Did It Happen? Can It Happen Again?
A step-by-step examination of various factors that were blamed for the extended power outage on the ERCOT electricity grid in February 2021 reveals that no single factor fully explains the calamity. The authors make several recommendations in this working paper.
ERCOT Generation by Resource: A Time-Lapse of Texas Fuel Mix in Electricity Generation
The Electric Reliability Council of Texas (ERCOT) manages the state’s power grid and serves over 25 million customers, or about 90% of the population in Texas. The state is the largest electricity producer and consumer in the nation. The tremendous growth in wind capacity in Texas also makes it the largest wind power producing state. A significant fraction of power demand is met by natural gas. Today, natural gas-fired power plants produce about half of ERCOT’s total electricity, followed by wind (20%), coal (16%), and nuclear (10%). In contrast, in 2009, natural gas provided about 48% of ERCOT’s total electricity output while coal and nuclear supplied 35% and 10%, respectively. Wind only constituted 5% of the fuel mix that year.
It is also important to recognize the seasonal and daily volatility of electricity, especially in a system like ERCOT where intermittent renewables like wind and solar are becoming increasingly important.
This time-lapse videos above show the daily electric generation by fuel within ERCOT from January 1, 2009, to November 2022 and will be updated twice a year. The chart displays the generation data at the 15-minute interval and is overlaid with the day ahead load forecast (projected demand) beginning June 5, 2011.
Generation resources include coal, natural gas combined cycle, all other natural gas, nuclear, petroleum, and renewables including hydro, wind, solar, and others, categorized by the legend.
We produced two versions of the time-lapse:
- Master (1.5x): Over 12 years of daily snapshots in 36 minutes.
- Fast-speed version (15x): Over 12 years of daily snapshots in just three minutes.
The full time-series from January 1, 2009, to November 2022, runs about 36 minutes. Users can quickly pinpoint a specific date during the time frame or utilize the time stamps below to reference major events. For convenience, we have also developed a version that concentrates the data into a 3-minute video to highlight the growth and evolution of the Texas fuel mix.
Below are the time stamps of major events impacting the ERCOT grid:
- 2011 cold snap — Master: 2/1/2011 at 05:22
- 2018 record heat within the time frame of the data set — Master: 7/23/2018 at 24:52
- 2020 July 11-14 record heat observed in Border and Del Rio, Texas — Master: At 30:02
- 2021 winter storm Uri — Master: 2/10/2021 at 31:36
The data is publicly available on ERCOT’s website.
See ERCOT's latest 2022-2023 Winter Seasonal Assessment of Resource Adequacy (SARA) here.
2021 Freeze: Generation by Fuel and Outages
Winter storm Uri struck in February 2021, causing historical, devastating impacts on the Texas power grid, managed by the Electric Reliability Council of Texas (ERCOT). All types of power generating resources experienced outages and derates under extreme cold weather. At the peak of the storm on February 16, over 30% of ERCOT’s winter capacity was offline. ERCOT was forced to issue load shed orders to maintain system stability. This included long periods of extended blackouts across the state, leaving millions of customers in the dark and cold for days.
So let us travel back in time to look at what happened between February 10 and February 28, 2021.
The time-lapse video above shows a side-by-side visualization of ERCOT daily electricity generation by resource (left) and Texas hourly power plant outages and customer outages (right) during the February freeze of 2021.
The left-side chart includes generation by resource at the 15-minute interval and day-ahead load forecast (projected demand). The right-side map illustrates Texas power plant capacity outages at the facility level (bubbles) and customer outages at the county level (filled map in blue shades). Also included are crude oil (green lines) and natural gas (red lines) pipeline infrastructure as well as the ERCOT service area (black line).