It’s over, for the moment: ERCOT, the company that manages the Texas utility system, said Monday that it doesn’t expect peak electricity demand this week to surpass last week’s record levels.
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As he did after a sudden freeze stressed the Texas system in February, ERCOT CEO Trip Doggett credited wind power with a critical contribution during last week’s power emergency. Doggett said electricity from wind farms recently installed along Texas’s Gulf Coast began flowing at just the right time to help meet peak demand in the late afternoons.
With that in mind, some lessons from the week’s real-world experience with substantial amounts of installed wind generating capacity on a large utility system:
Adding wind power makes a utility system more reliable, not less.
Balancing electricity supply and demand is a complex task, and utility system operators are used to turning various types of power plants on or off to match demand as it rises and falls throughout the day.
Even though wind energy is variable, it varies slowly–unlike conventional power plants, which can fail instantaneously–and can be a critical component in times of need. For three straight days in the real world last week, wind made the difference between keeping the lights on and the air conditioners running, and rolling blackouts.
No power plant runs 100% of the time.
Throughout last week’s heat wave, as in February’s freeze, the Texas utility system was bedeviled by outages of conventional power plants due to extreme weather. According to an August 2 blog article by Elizabeth Souder of the Dallas Morning News, “The high temperatures also caused about 20 power plants to stop working, including at least one coal-fired plant and natural gas plants.”
Souder noted that a spokesman for the Electricity Reliability Council of Texas (ERCOT), the company that manages system operations, “said such outages aren’t unusual in the hot summer…”
This is fascinating, since the rap on wind is that it’s not dependable because “sometimes the wind stops blowing.” In the real world, sometimes it also gets too hot or too cold for the supposedly dependable fueled peaking power plants to operate properly.
Geographic dispersal of wind farms makes their electricity production more dependable.
This is something that seems intuitively obvious–the wind is usually blowing someplace–and has been predicted by a host of studies. Last week, it became crystal clear, as the Gulf Coast wind farms, which provide some 13% of Texas’s overall wind generation, accounted for as much as 70% of the wind-generated electricity being provided during peak hours.
The reason for this is that winds are often low in west Texas, where most of the state’s wind farms are located, on very hot days, while ocean breezes blow more strongly.
Generation from offshore and coastal land-based wind matches up well with summer demand peaks.
Again, this is a phenomenon that has been predicted by studies. During a heat wave in the Northeast in July, Cape Wind, the company that hopes to install a large offshore wind farm off Cape Cod in Massachusetts, said its meteorological data showed the project would have been producing at full capacity during peak demand hours.
The Texas experience bears that out, with ERCOT CEO Doggett telling the Austin American-Statesman, “We’d love to have more development of coastal wind. And we’re hoping their ability to generate during the peak hours may encourage more development in that area.”
Denise Bode is CEO of the American Wind Energy Association.
