On Tuesday this week, while Florida transmission operators were getting everyone back online after a sub-station fire lead to cascading outages around the state, in Texas grid operators were responding to an emergency of their own. A sudden drop off in the West Texas wind produced an almost as sudden drop in wind power generation, from about 1700 MW to 300 MW. The Fort Worth Star-Telegram reported:
Operators of the Texas power grid scrambled Tuesday night to keep the lights on after a sudden drop in wind power threatened to cause rolling blackouts, officials confirmed Wednesday.
At about 6:41 p.m., power grid operators ordered a shutoff of power to so-called interruptible customers, which are industrial electric users who have agreed previously to forego power in times of crisis. The move ensured continued stability of the grid after power dropped to alarmingly low levels.
Dottie Roark, a spokeswoman for the power grid, said a sudden uptick in electricity use coupled with a sudden drop in wind power caused the unexpected dip. As a result, grid officials immediately went to the second stage of its emergency blackout prevention plan.
“This situation means that there is a heightened risk of … regular customers being dropped through rotating outages, but that would occur only if further contingencies occur, and only as a last resort to avoid the risk of a complete blackout,” the State Operations Center stated in an e-mail notice to municipalities.
The episode may embolden wind power critics — the Star-Telegram quotes an attorney as saying, “This is a warning to all those who think that renewable energy is the sole answer” — but I’d rather call it a reminder rather than a warning.
After all, other than some industrial customers who voluntarily shut down, and who are compensated for standing ready to shut down on short notice, no one in the restructured Texas power market lost power on Tuesday night. A rare event happened and from public reports it appears that existing, standard reliability measures at ERCOT, the state’s integrated power market and transmission system operator, were sufficient to keep the system running.
If wind is more susceptible to such swings in output than other generators — and it is — efficient coordination of the power system simply requires ensuring that such generators pay the right price for the additional reserves or other measures needed to maintain system reliability.
And, by the way, as a follow-up story notes, in addition to the sudden drop off in wind generation the ERCOT system was also faced with “a failure of several [other] energy providers to reach scheduled production.” It isn’t just wind that shows some variability in output.