by Denise Bode, CEO,  American Wind Energy Association.

The Horse Hollow Wind Energy Center in Texas boasts 291 GE 1.5 MW units and 130 Siemens 2.3 MW turbines. Turbines like these near the Texas coast were productive during the Texas heat wave of 2011.

In contrast to the comments on some ill intentioned blogs, ERCOT (Electricity Reliability Council of Texas) CEO Trip Doggett credited wind power with a critical contribution during the summer power emergency in Texas. He did the same after a sudden freeze stressed the Texas system in February. Doggett said electricity from wind farms installed along Texas’s Gulf Coast began flowing at just the right time to help meet peak demand in late afternoons. With that in mind, we present a few lessons learned from 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. ERCOT’s Trip Doggett credited wind power with a critical contribution during a power emergency (in the summer of 2011). Doggett said electricity from wind farms that had been recently installed along Texas’s Gulf Coast began flowing at the right time to help meet peak demand.
  Balancing electricity supply and demand is a complex task, and utility system operators are accustomed 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, 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 the heat wave, as in February’s (2011) 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 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 obvious–the wind is usually blowing someplace–and has been predicted by a host of studies. (In the 2011 Summer heat wave) 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 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.”

AWEA
www.awea.org