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Debunking Myths about Wind Energy

December 1, 1994
Paul Gipe

Public Safety and Setbacks


 

 


Excerpted from Wind Energy Comes of Age by Paul Gipe, John Wiley & Sons, Inc New York (1995), pages 361-364, ISBN 0-471-10924-X. This except is provided as public service and can be viewed at Google.com. This is the original unedited text. .


"Danger-Wind Turbines," proclaim signs prominently posted every several hundred feet along the perimeter of California's wind plants. They make great fodder for opponents of wind energy, who like to point to them and say "See, we told you they were dangerous, malicious monsters devouring our landscape."1 The signs imply a degree of risk that is nonexistent, and are an outgrowth of California's litigious legal environment, and nothing more. They respond to county regulations governing what planning officers and lawyers describe as "attractive nuisances," anything that attracts trespassers who may subsequently injure themselves. Europeans find the concept hard to grasp: that someone who climbs to the top of a tower and injures himself in the process has a legal claim against the owner. Europeans still have the innocent view that individuals are least partly responsible for their own actions.

Despite the signs, and despite the rare catastrophic destruction of a wind turbine, no member of the public has ever been injured by a wind turbine. To Swiss analyst Andrew Fritzsche, the operation of wind turbines is "practically risk-free for the public." In contrast to other energy sources, renewables "have practically no potential for severe accidents" that would endanger the public.2

An incident in the spring of 1981 illustrates the difference between energy technologies, regarding risk to the public. California's Governor Jerry Brown planned to launch what would become the world's largest wind industry at a conference in Palm Springs. The featured event of the conference was Alcoa's demonstration of its new Darrieus wind turbine, operating at Southern California Edison's nearby test center. Just prior to the conference, a malfunction in the turbine's controller led to the turbine's destruction. Grim-faced but retaining his sense of humor, Alcoa's program manager Paul Vosburgh addressed the gathered dignitaries and announced "I have some good news and some bad news. The bad news is that our wind turbine has destroyed itself. However, the good news is that we did not have to evacuate Los Angeles." His reminder of the 1979 nuclear accident at Three Mile Island near Harrisburg skillfully turned attention from the pubic relations fiasco to wind's promise as a more benign technology.

During tumultuous public hearings in Tehachapi in the early 1980s, some fearful residents charged that the unreliable wind turbines then in use would throw parts long distances, thus endangering them and their families. Wind turbines, notably during the technology's early days, have indeed self-destructed, and falling components have damaged trucks, trailers, and even nearby wind turbines. Some machines, such as the Storm Master, have thrown parts several hundred meters. And in Denmark, where the turbines are often located close to inhabited buildings, broken blades have landed near the homes of their owners. Yet no one has been injured, either in Denmark or in California, and damage has been limited to the area near the turbine. After examining several wind turbine failures in Europe and the United States, Alexi Clarke concluded that the risk of being hit within 210 meters (700 feet) of a wind turbine is comparable to the risk of dying from a lightning strike; beyond 210 meters, the risk is even lower.3

Setbacks from habitation of 150-300 meters (500-1,000 feet), sufficient to reduce the noise and visual impacts of commercial wind plants, are more than ample to protect public safety. Noise setbacks are derived from projections of noise impact, and can vary with the noise strength and the number of wind turbines proposed. The noise setback from a single low-noise turbine falls at the lower end of the range. Noisier machines require a greater separation distance. Such setbacks are unwarranted on safety grounds alone.

Derek Taylor, in a study for Dyfed County, Wales, concluded that setbacks of 120-170 meters (400-600 feet) were sufficient to protect habitations, and that only 50-100 meters (150-350 feet) were needed to protect the public using nearby roadways. To minimize complaints from neighbors about noise and shadow flicker, Taylor recommends a 300-meter setback from nearby dwellings, twice that needed to protect public safety.4

The perceived risk from wind turbines has led some communities, mostly in California, to establish setbacks or buffer zones between the wind turbines and their neighbors. See Table 13-1. The need for these buffer zones to separate wind turbines from homes and public facilities remains controversial, even though it has been 15 years since the question was first raised. Intended to compensate for the involuntary risk of real or imagined hazards which are borne by the public, setbacks impose a standard on wind turbines not applied to all other technologies or comparable land uses.

Table 13-1

In California, setbacks are sometimes given in multiples of the wind turbine's height. For example, in Kern County, which administers California's Tehachapi Pass, wind turbines must be set back from roads and trails a distance of 1-1/2 times the total height of the turbine (hub height plus rotor radius). For a 40-meter turbine on a 40-meter tower, the setback is 90 meters (300 feet). In Palm Springs, where local officials have been less receptive to wind energy than in Kern County, setbacks are greater. The buffer zone of 6 times the total height from a parcel with a habitation prohibits the installation of the 40-meter turbine in the example closer than 360 meters (1,200 feet) from the lot line.

Safety setbacks are unnecessary in some cases, such as with individual wind turbines, and should never impinge on individuals who voluntarily choose to accept the risk: those who want to install wind turbines near their own homes or who grant easements for others to do so. If the setbacks in Table 13-1 had been applied to individual wind turbines and not just to California wind plants, most of the wind turbines in Denmark and nearly all of the 5,000 small wind turbines in the United States would never have been installed. These machines were deliberately located by their owners near their homes or businesses for their own benefit, and few had to comply with setback standards such as those in Table 13-1.

In the United States, safety buffers from some individual turbines at suburban locations have been required. Often this is equivalent to the height of the turbine, so that if the tower collapsed, it would not extend across the property line.

Planning officers must have sufficient flexibility to exclude individual wind turbines or small clusters of turbines from restrictive setback requirements; otherwise, they discriminate against wind energy as compared with other technologies. Wind turbines are no more dangerous to their owners, or to the public, than other sources of energy that course through our homes and workplaces every day. Natural gas, fuel oil, and electricity all impose risks that we willingly accept. We also willingly accept the public risk imposed by our neighbors' use of these technologies. The same standards should be applied to wind energy. Nothing more, nothing less.

Setbacks on aesthetic grounds may be appropriate for commercial wind power plants comprising tens of machines. For example, Palm Springs requires a scenic setback of 500-3,500 feet (150-1000 meters) from designated roads leading into the resort city nestled at the base of Mount San Jacinto. But the impact of hundreds of wind turbines on the landscape differs markedly from that of a single turbine. Most landscapes can easily assimilate a few scattered wind turbines. Thus, setbacks for single wind turbines on grounds of either safety or aesthetics are inappropriate.

Europeans are more tolerant and less fearful of wind turbines in their communities than Americans, possibly because of their prior experience with the technology. In at last three officially-sanctioned settings in the Netherlands, visitors can stroll unhindered among operating windmills: at Arnheim's open air museum, at the 17th century "windfarm" of Kinderdijk, and at the recreated Dutch village at Zaanse Schans. In each case, the windmills are fully accessible to visitors. Tourists can also visit hundreds of other operating windmills throughout the country.

Modern wind turbines are equally accessible. In 1992, a restaurant on the autobahn near Aachen installed a 150 kW wind machine; a McDonald's restaurant near the north German port of Kiel installed a Ventis wind turbine (dubbed "McVentis" by local journalists) in its parking lot. It is the same across northern Europe. An 80 kW Lagerwey turbine operates prominently at a lock on the northern end of the Afsluitdijk, the dam closing the former Zuider Zee. The turbine stands within 50 meters (150 feet) of the heavily traveled route, in plain view of traffic which frequently stops for the lock. Nearby, a Lagerwey and an Aerotech spin merrily near the parking lot of a restaurant just off the motorway. In Montabaur, provincial capital of Germany's Westerwald, a small wind turbine whirring away on a roof-top in the city center stirs little interest from pedestrians on the street below. These and countless examples in Denmark prove that the public need not fear wind turbines, and that setbacks are sometimes inappropriate.

1. See the cover photo for the September 1993 issue of the Santa Monica Bay Audubon's newsletter. The quote summarizes both the content and the tone of the article. Steve Ginsberg, "The Wind Power Panacea: Is There Snake Oil in Paradise?," Audubon Imprint, Santa Monica (Calif.) Bay Audubon, 17:1, September, 1993, 1-5.

2.Andrew F. Fritzsche, "The Health Risks of Energy Production," Risk Analysis, 9:4, 1989, 565-577.

3. Alexi Clarke, "Windfarm Location and Environmental Impact," Natta, The Open University, Milton Keynes, England, June, 1988, 55-57.

4. Derek Taylor and Marcus Rand, "How to Plan the Nuisance Out of Wind Energy," Town and Country Planning, May, 1991, 152-155.


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