According to the Associated Press, high electricity demand and "maintenance issues" at generating plants has led Xcel Energy to declare an energy alert in its Texas and New Mexico service territory. Xcel Energy urged customers to cut back on their use of electricity until 8 p.m. Tuesday. It would seem to be a sign of things to come in the future as the EPA takes step after step to systematically remove coal-fired power plants from service in virtually every state in the nation without sufficient base load replacements.
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I would sure like to know where these EPA officials live and work.
Before anyone gets their daily exercise jumping to conclusions, be advised that Xcel Energy advertises themselves as "the nation's number 1 wind power producer", and in the TX-NM service area, 16% (673 MW) of Xcel's capacity is wind power. (50% is coal-fired, 32% is NG-fired steam turbines and 2% is NG gas turbines.) In other words, one-sixth of Xcel's TX-NM power production capacity is from wind.
We'll see what the actual ERCOT wind production numbers are when they do the daily update to the August wind integration report, but on Aug 22nd, wind in TX peaked at 10% of rated capacity shortly after midnight and then hit a low of less than 2% of rated capacity in the early afternoon. On aug 22nd, wind operated at less than 3% of rated capacity from 11 am to 10 pm. While ERCOT doesn't publish numbers on individual wind farms, I can't imagine that Xcel's wind input (all of which is purchased in the TX-NM service area) was going gung-ho while the rest of TX wind frankly sucked.
http://www.ercot.com/gridinfo/generation/
So with the high demand and Xcel's 673 MW of wind capacity actual producing between 67 and 13 MW, Xcel has to be running their other plants pretty hard, and has probably been doing so all month. their two coal plants were built between 1976 and 1982, and their three NG steam plants were built between 1952 and 1974, so none of them are spring chickens, even if they have been well maintained.
Follow-up: Looking at the ERCOT data for 8/23/11, once again, TX's wind resources peaked at 1:44 am at about 11% of rated capacity, then dropped, running at less than 3% of rated capacity from 12 noon to 10 pm.
My bad. The percentage numbers that I was reporting above were the wind output as a percentage of the total ERCOT load. In the same ERCOT link, the graph above the one I was reading presents the wind output as a percentage of total wind capacity, which is typically hitting a peak of 40-45% in the wee hours of the morning, then droping to less than 20% capacity of the rated output for the period of 10 am to 10 pm. (That's by no means great, or even good, but a whole lot better than 2-3%.) What we are not seeing is the minute-to-minute variations in wind output, which can be seen on BPA's near-real-time graphs:
http://transmission.bpa.gov/Business/operations/Wind/baltwg.aspx
The hourly "smoothing" of the ERCOT graphs is something well known in the wind industry, which expects metrological data recording at intervals of 10 minutes or less.
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