[Updates below after the graphics] According to the National Weather Service, “an upper-level high over the south-central portion of the country, along with high temperatures and temperatures not cooling off much overnight, have contributed to Excessive Heat Watches/Warnings and Heat Advisories over most of Texas, southern New Mexico/Arizona, southeastern Oklahoma, Louisiana, Arkansas, Mississippi, and western Tennessee.” (See graphics below and specific forecasts here and here and here.)
The intensity of this week’s heat over such a wide area involving several significant population concentrations will stress grid capacity and continuity. (Significant force prompting wide-area, unpredictable demand for essentially fixed supply capacity (more).)
As noted last week, the ERCOT dashboard provides near real-time capacity, supply, and demand information. In recent days, solar has often exceeded anticipated capacity, while natural gas has contributed less. Wind has been, well, variable: some days delivering more than anticipated, other days less. Wind speeds could make a crucial difference this week. As of Sunday afternoon, Tuesday’s wind speeds are forecast to be ten or less miles-per-hour. Wednesday’s wind speeds are forecast at between 9 and 14 MPH. (More and more and more.) For current proportional flows, see “fuel mix” on the ERCOT Dashboard.
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June 27 Update: Monday’s demand for electricity across Texas fell just short of the record. Every type of fuel delivered as needed. Natural gas usage has hit a new record. According to S&P Global, “As the National Weather Service issues excessive heat warnings for dozens of counties across central Texas, gas-fired power burn demand has surged to an average 7.1 Bcf/d over the past week – about 1 Bcf/d above the prior three-year average and a new record high for late June… ” Tuesday’s projected supply from all sources exceeds projected demand by more than 10,000 MW despite even higher projected heat (here and here and here and here).
Bloomberg has a detailed piece on systemic problems complicating the contribution of natural gas to electric generation.
June 28 Update: Tuesday’s demand for electricity hit a new record (here and here and here and here). Despite the high heat and 80,875 MW pull, an almost 7000 MW buffer (operating reserve power) was maintained (more and more and more).
July 1 Update: S&P Global provides a concise after-action and look-ahead, “The heat wave that spread triple-digit high temperatures across the Electric Reliability Council of Texas footprint since mid-June has dissipated, slackening power demand forecasts for the first week of July, but substantially weaker wind forecasts have boosted day-ahead prices for July 3 delivery. CustomWeather forecast highs to average 96 degrees F July 3-7 for the Dallas metro area, up about 1.5 degrees from normal for those dates but down about 2.5 degrees from the National Weather Service’s average highs June 26-30. ERCOT’s 2:30 pm CT (June 30) load forecast shows peakloads averaging 76.3 GW July 3-7, down 4.7% from the July 26-30 average of about 80 GW.” I perceive that one factor that helped was a purposeful, prudent decision to over-estimate demand. This signal served to maximize production potential and output. This reflects the lessons of Winter Storms Uri and Elliott applied to summer extremes.