Wind forecasting has certainly improved from 40 years ago, but its reliability then, and now, is irrelevant. A 100% accurate forecast of wind doesn’t boost the low efficiency of wind turbines.
The July 13 letter from Rob Gramlich of the American Wind Energy Association makes a number of unsupportable statements, the most egregious of which is “grid operators can easily manage variability from wind.” He further stretches the truth with “advances in wind forecasting have now made wind energy even more reliable.” Both statements are unsupported by the facts. Wind forecasting has certainly improved from 40 years ago, but its reliability then, and now, is irrelevant. A 100% accurate forecast of wind doesn’t boost the low efficiency of wind turbines.
An industrial wind facility (IWF) operates with turbines that produce about one-third of their rated output. That means they will supply somewhere between 0% and 100% of their capacity but will average only a third of that capacity. This large difference between their maximum output and their actual output means that the electric grid must be able to accept, and use, not the “20% of the electricity in 23 states” that Mr. Gramlich claims, but between 0% and 60%. No matter the reliability of wind forecasts, no grid can be so accommodating. The only way to accommodate such surges is to curtail either these wind surges or shut down other, cheaper and more reliable suppliers. The first would so reduce the efficiency of wind as to make it laughable. The second would necessitate shutting down base load suppliers, the cheapest and most reliable of all sources. A simple analysis of wind data in the U.S. shows that wind speeds are highly synchronized over very large areas. This means that when one IWF is producing lots of energy, all the others, within a few hundred miles will be too. Such synchronized surges mean that grid operators cannot easily manage variability from wind.
The net is that until wind turbines can be highly efficient (75+%) they will never be a serious competitor with other sources. No one expects Mother Nature to be so cuddly. No one-third efficient source of energy can be useful to the electric grid, no matter its source.
[NWW: It important to note, as in this letter, not only that average generation masks a great variability, but also that the cubic relation of wind speed to power generation means that any wind turbine or group of wind turbines produces at or above its average rate only about 40% of the time, with the rate quickly approaching zero the rest (~60%) of the time.]
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