Howard C. Hayden
January 12, 2001
The Denver Post
Editorials are traditionally placed in the section reserved for opinions; actual news is normally placed on the news pages. However, the 1/07/01 issue of The Denver Post has Michael Booth’s blatantly political opinion piece on the front page, entitled, "Energy Solution: Blowin’ in the Wind? Xcel seems reluctant to invest in cost-competitive power."
I therefore offer the article on the next page as a guest editorial. To introduce myself, I am a Professor Emeritus of Physics, recently retired from the University of Connecticut, where I went directly after receiving my Ph.D. in physics at the University of Denver.
Howard C. Hayden
Howard C. Hayden, Professor Emeritus of Physics, University of Connecticut
In Cervantes’ comical Don Quijote de la Mancha, the most famous escapade of our hero was his attack on a windmill that he mistook for a sword-wielding giant. Modern armchair engineers with equal wisdom mistake windmills for giant free-energy machines.
Even without detailed knowledge of wind turbine design, the intelligent reader should be slightly suspicious about the current pro-windmill exuberance in newspaper articles such as that by Michael Booth, 1/07/01 ("Energy Solution: Blowin’ in the Wind? Xcel seems reluctant to invest in cost-competitive power"). After all, since wind energy schemes have a thousand-year head start, there must be some reason or reasons why wind makes so little contribution to our energy picture.
Similarly, it does not take a Ph.D. in economics to know that utilities have been spending enormous amounts of money for coal or natural gas to produce electricity. Any red-blooded capitalist would jump at the chance to produce "free" electricity, thereby to increase profits. But utilities haven’t fallen in love with wind turbines, so there must be some reasons.
One can hardly fail to notice that California is experiencing an energy crisis after decades of embracing, supporting, and subsidizing windmills. California has some 3200 wind turbines that, combined, produce only about 1.1% of California's electricity. Their present dilemma is rooted in the delusion that piddle-power sources could provide electricity for their burgeoning economy.
Wind has its uses, but providing steady power is not one of them. If the wind speed drops from 10 miles per hour to 9 miles per hour — a mere 10% drop — the power available from a wind turbine drops almost 30%. If the wind speed doubles from 10 mph to 20 mph, suddenly there is eight times as much power available. These rules are due to the air itself, and have nothing whatsoever to do with windmill design. Wind turbines produce the lowest-quality electricity on the planet.
Suppose a wind turbine is designed to tolerate 30-mph winds. The power it could produce under these maximum-wind conditions is called the nameplate power, or its capacity. Most of the time, the turbine will be in 10-mph winds, producing only one twenty-seventh (less than four percent) as much power as its nameplate would suggest. That’s about like having an engine from a muscle car on a riding lawnmower, "just in case you need it."
But even if California had 100 times as many windmills --- 320,000 windmills --- could they get 100% of their power from windmills? Not a chance. Most of the time, the windmills would produce very little power, and, of course, when there's no wind, there's no power at all. At those times, other power sources have to be ready to produce 100% of the power requirements. In short, windmills do not allow any other power plants to be taken out of service.
In the several times per year that the winds were strong enough that the windmills could produce their full capacity, the 320,000 hypothetical windmills would produce about five times as much power as California needed at the moment. Under those circumstances, about 80% of them would simply have to be turned off, because at all times the power put into the grid must equal the power consumed.
The variability of wind power tells yet another story. The amount of power is determined not by the consumer who needs the power, but instead by the available wind. That is, you cannot flick on a switch to increase the wind speed. If you want power, you wait for the wind.
The job of any wind turbine is to extract energy from the wind, thereby slowing the movement of air. Therefore the wind turbines must be widely spaced so that they are never in the lee of each other. I quote from an article on the EPA website. "Contemporary wind projects are typically rated at 25 to 100 MW. A 25 MW project might have 60 to 70 turbines covering 1500 acres." One MW is a megawatt, one thousand kilowatts, the average per-capita electrical power usage of about 900 US citizens.
Let's translate those numbers. Twenty-five megawatts divided by 1500 acres is 16.7 kilowatts per acre, but that's using the nameplate value, which is about five times higher than the average value. This translates into an average of about 3.3 kilowatts per acre. Assuming ideal conditions, to produce as much energy in a year as a single 1000-MW electrical power plant would require about 13,000 wind turbines on about 470 square miles of land area. That’s about the area that would be bordered by Route 470 on the west, south, and east, and by 88th Street on the north. Picture that amount of land covered with huge windmills that produce unreliable electricity. And even ideally, they would produce not even half of the electricity used in the Denver metropolitan area.
The attached picture (from http://www.nrel.gov/data/pix/Jpegs/01232.jpg) thirty wind turbines at Altamont Pass in California. Notice that the wind turbines dwarf the building in the foreground.
In recent years, the little country Denmark has gained a certain amount of fame with its wind turbines. No, they don’t get much electricity from them. They sell them to suckers.