Assessing the limitations of just-in-time energy delivery in the ERCOT interconnection

In February of 2021, an atypical continental weather pattern imposed lower-than-average temperatures on the southern U.S. Prolonged subfreezing temperatures in turn put substantial strain on Texas’s energy systems. The electric grid of Texas, operated by the Electric Reliability Council of Texas (ERCOT), was crippled by a number of technical and operational difficulties initiated by the extreme weather. Freeze-offs on natural gas equipment and wind shortages resulted in significant under-generation, at times approaching 50% of load forecasts. Blackouts and prolonged rolling outages were the result. These rolling outages, necessary to retain broader stability and grid synchronism, proved effective in providing necessary grid stabilization. However, such actions left millions of Texas residents without power, heat, water, and other life sustaining resources during several of coldest days in recent memory, causing hundreds of fatalities. Analysis of the event indicates that the lack of both sufficient baseload and dispatchable generating capacity is the result of a number of interweaved operational constraints placed on grid operators by alterations in the interconnection’s fuel resource availability. Fuel supplies are no longer readily stored on-hand in sufficient quantity, and just-in-time delivery creates dependence on suppliers who are themselves subject to the forces of extreme weather.