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February 19, 2021

Extreme winter weather is disrupting energy supply and demand, particularly in Texas

hourly electricity demand, net generation, and total interchange
Source: U.S. Energy Information Administration, Hourly Electric Grid Monitor (ERCOT demand, net generation, and interchange)

Last weekend, a major winter weather system characterized by extreme cold spread across much of the central United States, disrupting energy systems and causing serious health and safety issues, particularly in Texas. At the same time that the cold weather increased energy demand, it also affected energy supply, causing intense and widespread energy market disruptions. Notably, electricity deliveries have been disrupted in the parts of Texas served by the Electric Reliability Council of Texas (ERCOT) as a result of various issues related to plant operations.

Natural gas wells in the region have been affected by freezing temperatures that have disrupted production, and pipeline compressors have lost power, which have both reduced deliveries. Refineries in the area have halted production. These energy market disruptions may continue for the next several days, and it could take weeks for energy systems to resume normal operations. The U.S. Energy Information Administration (EIA) has several data resources that can provide context to current U.S. energy markets.

Customers across Texas have experienced widespread electric service outages, especially within areas managed by ERCOT, a nonprofit corporation that manages the supply and distribution of electric power to 26 million customers in Texas, covering about 75% of the state’s territory and 90% of its electric load.

EIA’s Hourly Electric Grid Monitor (Grid Monitor) shows that electricity net generation fell below ERCOT’s day-ahead forecast demand shortly after midnight on February 15, and that trend persisted through February 18. The mismatch between demand and day-ahead forecast demand quickly grew to at least 30,000 megawatts (MW) on February 15 before eventually narrowing to slightly less than 20,000 MW by February 17.

One way to calculate the approximate extent of the mismatch is to compare actual demand against ERCOT’s demand forecast issued before implementing rotating outages. ERCOT has received little power supply from outside the region (interchange) during this disruption period. ERCOT became the country’s first Independent System Operator (ISO) in 1996, when it was reorganized from a reliability council into an ISO. It schedules power delivery on an electric grid connected by more than 46,500 miles of transmission lines and about 700 generation units. One of the key features of ERCOT is its tightly controlled electric network; it has few connections to grids outside the state.

Natural gas is the largest source of power generation in ERCOT, providing for more than 40,000 MW of supply during peak periods. Grid Monitor data show that natural gas-fired power generation fell sharply once ERCOT began implementing rotating outages at midnight on February 15. Output from coal-fired plants, a nuclear facility, and wind farms all fell near midnight on February 15 and remained at the lower level.

hourly net generation by energy source
Source: U.S. Energy Information Administration, Hourly Electric Grid Monitor (ERCOT net generation by energy source)

EIA’s Grid Monitor provides insights into the current status of the electric grid across the Lower 48 states. The data include hourly electricity generation by energy source, electricity demand, interchanges, and day-ahead hourly demand forecasts. These data series are available for each of the 64 operating balancing authorities (BAs) in the Lower 48 states and several subregional areas. Users can generate custom dashboards that they can save and share. EIA collects the data directly from BAs using automated processes and publishes the data in real time, which can result in anomalous data values. EIA continuously works with respondents to correct anomalous values for the historical record.

To track up-to-date information as this energy market disruption continues to unfold, visit EIA’s Grid Monitor and other related energy resources on the EIA website.

Principal contributor: Mark Morey