Wind Farms And Doppler Radar Just Don’t Mix
August 31st, 2009
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It’s been well known for some time that those enormous wind turbines cause problems when it comes to radio signals. When large numbers of massive spinning blades are packed together, they can create a situation where the terrain characteristics for radio reflection are in constant flux. This can make it difficult for tuners to lock on to signals and adjust the gain, because as soon as a good stable signal is received, a blade swoops by and causes a wicked reflection or otherwise changes the signal characteristics.
This problem has shown up before with television signals and military and air traffic control radar.
Now there’s a new concern over wind turbine interference: Doppler radar.
SIOUX FALLS, S.D. — Wind farms have been blamed for disrupting the lives of birds, bats and, most recently, the land-bound sage grouse.
Now the weatherman?
The massive spinning blades affixed to towers 200 feet high can appear on Doppler radar like a violent storm or even a tornado.
The phenomenon has affected several National Weather Service radar sites in different parts the country, even leading to a false tornado alert near Dodge City, Kan., in the heart of Tornado Alley. In Des Moines, Iowa, the weather service received a frantic warning from an emergency worker who had access to Doppler radar images.
The alert was quickly called off in Kansas and meteorologists calmed the emergency worker down, but with enough wind turbines going up last year to power more than 6 million homes and a major push toward alternative energy, more false alerts seem inevitable.
New installations are concentrated, understandably in windy states like Texas, Oklahoma, Kansas, Colorado and Iowa, all part of Tornado Alley.
Texas, which has more tornadoes than any other state, also has the most wind power capacity.
…
Problems began to surface about three years ago, and seem to occur where a wind farm is built within about 11 miles of a Doppler site, said Tim Crum, with the weather service’s radar operations center in Norman, Okla.
That could become a bigger problem because the same terrain is attractive for both weather radar and wind farms.
“They want to be out in relatively exposed areas, high terrain, those sorts of things,” Crum said. “So we sometimes are looking for the same ground, although we’re already there.”
Software can easily filter out buildings, cell towers and mountain ridges on radar screens. Yet because weather radar seeks motion to warn of storms, there’s no way to filter out the spinning blades.
Given that Doppler radar operates by receiving reflections of radar energy and measuring the frequency shift, it shouldn’t be a real surprise that something like a big spinning blade would tend to interfere with the systems. At this point it’s not entirely clear whether this is caused entirely by the blade motions or whether the vortexes of air created by the turbines may play a role in this. One thing is for sure, however, if more and more turbines are built, this will become a bigger issue, and if very large wind turbines are built offshore, it could make for difficulty in observing weather patterns like hurricanes and tropical storms at sea and getting good data for weather forecasting.
This problem is not isolated to just the areas mentioned in the article quoted above. Issues have arisen at radar sites in the North East US, Pacific Northwest and Europe. The image above and to the right is from Western New York State.
It is important to note that all industrial facilities do have some impacts and costs associated with their construction. Even nuclear power plants occupy land and may not provide most scenic vista for those living in the area around them. The problems posed by wind turbines, including both radar and signal interference as well as issues like shadow-flicker and bird strikes would be worth managing and tolerating if the return was large amounts of economic, clean and reliable energy. Unfortunately, it is not, and therefore these costs come with little, if any return.
More info is avaliable from the US National Oceanic and Atmospheric Administration’s Radar Operations Center. Apparently this has become an issue of major concern to NOAA.
This entry was posted on Monday, August 31st, 2009 at 11:25 pm and is filed under Bad Science, Enviornment, Good Science, Misc, Politics. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.
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September 1st, 2009 at 12:25 am
Ah wind generation – the gift that keeps on giving.
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September 1st, 2009 at 1:54 am
Oh, big wind farms can destroy radio reception for all kinds of signals. Usually it’s not so bad for telephone, but for television it can make it impossible to get signals for miles. What happens is that if you get a reflection off of a building or something with analog tv then the signal will ghost but it has to be pretty bad for that to happen, but with a wind turbine it’s not a constant reflection. The signal jitters as the turbine comes across and the reflection cycles with multiple turbines. Since tv is AM that causes the signal to go in and out and the sync gets lost or you get pulses on the TV.
They claimed this would be fixed when we went digital. It wasn’t. Digital signals have built in error correction to deal with the delayed signals from reflection and ignore that, but with the turbines spinning, there is not a constant kind of delay and you get the signal chopping in and out so that the receiver can never figure out what is the proper one. Also, the same AM pulses coming in and out, it can mean loss of bits in the interferance and you cna only lose so much.
Digital can be worse because in some circumstances analog tv comes in poorly but digital just does not come in at all. You can get a box where it is telling you that the signal is strong but it gives you a blank screen because signal to noise is so poor.
Turbines on a ridge in the right spot can make this happen for miles.
The funny thing about it is that this is worst to those who don’t watch a whole lot of tv because they are the ones without cable or satellite. Poor sap just wants to watch the evening news or Jeopardy, but there is an up shot, which is that sometimes the wind farm finds the cheapest thing to do is pay for cable for everyone.
Still, pain in the ass really. Of course, TV is not as critical as something like radar.
You’re right that we could tolerate this, move our radar stations, pay for cable and everything if we got back many gigawatts of good reliable electricity. Then it would be fair to put up with that crap for the return. The problem is cost/benefit.
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September 1st, 2009 at 2:19 am
Pictures from the energy companies show slim towers rising cleanly from the landscape or hovering faintly in the distant haze, their presence modulated by soft clouds behind them. But a 200- to 300-foot tower supporting a turbine housing the size of a bus and three 100- to 150-foot rotor blades sweeping over an acre of air at more than 100 mph requires, for a start, a large and solid foundation. On a GE 1.5-MW tower, the turbine housing, or nacelle, weighs over 56 tons, the blade assembly weighs over 36 tons, and the whole tower assembly totals over 163 tons. A typical turbine site takes about a 42×42-foot-square graveled area. Each tower (and a site needs at least 25-35 towers to make investment worthwhile) requires a huge hole filled with about 1,250 tons of steel rebar–reinforced concrete in a hole large enough to fit three double-decker buses for each foundation.
The destructive impact that such construction has, for example, on a wild mountain top, is obvious. Erosion, disruption of water flow, and destruction of wild habitat and plant life continues with the presence of access roads, power lines, transformers, and the tower sites themselves. For better wind efficiency, each tower requires trees to be cleared. Each tower should be at least 5-10 times the rotor diameter from neighboring towers and trees for optimal performance. For a tower with 35-meter rotors, that is 1,200-2,400 feet, a quarter to a half of a mile. A site on a forested ridge would require clearing 45-90 acres per tower to operate optimally (although only 4-6 acres of clearance per tower, the towers spaced every 500-1,000 feet, is typical, making them almost useless when the wind is not a perfect crosswind).
I have to laugh at some of the things I hear coming out of Vermont these days (their radio and television stations are almost local in Montreal) with activists turning themselves inside-out trying to shut down the nuclear plant there. In Vermont, billboards are banned from the highways, and development — especially at sites above 2,500 feet — is subject to strong environmental laws, yet many of these same idiots who call themselves environmentalists absurdly support the installation of wind farms on mountain ridge lines as a desirable trade-off, ignoring wind’s dismal record and the damage it will cause.
Very strange from a State that I have spent a great deal of time in and have generally found to be a pillar of commonsense.
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September 1st, 2009 at 2:28 am
DV82XL said:
Well, if they get their way and have a few thousand wind turbines erected then you won’t be getting too many radio or tv signals from Vermont anymore
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September 1st, 2009 at 3:25 pm
I find the turbines beautiful and majestic because they symbolize our change to working with the earth. There are some who live in the shadows and they are bothered. That is a shame. Maybe they will have to be moved or something, but it is a small price to pay for going with clean power. The idea that they hit birds is overrated. This has been proven to be simply a way for big oil and nuclear companies to try to make them seem bad for the ecosystem and not good. We may also need to move radar or tv antennas. So what? It would be better then them being under water from sea level rise. In the near future storms will be so bad they will blow them down anyway, unless we change.
Wind and solar give plenty of power if we conserve. It will not if we continue to use air conditioners and big televisions and all those toys we selfishly love. That needs to end soon. It will end soon.
Nuclear is not the answer. It makes as much carbon and it is a huge danger of radiation.
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September 1st, 2009 at 5:31 pm
Driving the desire for industrial wind power is the conviction that it will help reduce fossil and nuclear fuel use. Thus the local impacts of large wind turbine installations are thought to be justified by a greater good of healthier air and water, reduction of carbon emissions, and moving away from harmful mining and fuel wars.
However wind is similar to solar in that it is not dependable. As a consequence they have to be backed up by natural gas generators which often must run over fifty percent of the time or more. Fluctuations in wind output have to be managed by the operation of fossil-fired capacity below optimum efficiency in order to stabilize the grid. This is because the rate of change of wind speed can drop faster than the rate at which fossil-fueled capacity can be started up. Hence spinning reserve is essential. The result is that, while wind-generated power itself is CO2-free, the saving to the whole power system is not proportional to the amount of fossil-fueled power that it displaces.
The wind power industry tends to downplay its negative effects, claiming that “every kilowatt-hour generated by wind is a kilowatt-hour not generated by a dirty fuel.” Such a formula is, at best, overly simplistic. The evidence from countries that already have a large proportion of wind power suggests that it has very little, if any, effect on the use of other sources. Wind plants, it seems, add more capacity (requiring more infrastructure) with almost no reduction of non-wind capacity, the latter of which must be used more inefficiently than otherwise.
The best inland windfarm sites tend to be where air funnels through passes in the hills that are also commonly flyways for birds. The bird kills have caused the Audubon Society to file suit in some areas to prevent wind energy installations. The Audubon Society is hardly a tool of big oil and at any rate, the end product is electricity, no significant replacement for petroleum.
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September 1st, 2009 at 5:47 pm
Victor said:
Windmill tinker-toys do not work with nature. They pave over vast amounts of land in return for weak, intermittent power that is more of a nuisance than anything else.
Victor said:
Who do you think is pushing these windmill tinker-toys? Have you seen a “Beyond Petroleum” add recently? It’s nothing but windmills.
Victor said:
Windmill tinker-toys will not stop climate change. The Germans have been building them faster than just about anyone else for over a decade. The result; Not a single coal plant has been shut down (in fact, they’re building more) and they’re more dependant on Russian natural gas than ever.
Victor said:
Wind and solar cannot power our civilization without a massive human die-off. Is the death of millions worth it just so the lucky few left at the end can live on tinker-toy power?
Victor said:
There is no credible radiation danger. Nuclear plans emit far less radioactivity than the coal plants they displace.
Nuclear power plants do not emit CO2.
There is some CO2 emitted during construction mostly from concrete but windmill tinker-toys use more concrete per MW and vastly more per MWhr than nuclear. Some CO2 is emitted during portions of the fuel cycle. This of course could be eliminated if enrichment, fuel fabrication and such were powered by carbon free nuclear produced electricity. So I guess your argument here is that nuclear isn’t nuclear enough.
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September 1st, 2009 at 5:49 pm
Current energy generation from wind is well under 1% in the US and already we have several Doppler radar sites that have been effected by these wind farms. We have already had to move airport radars or put them on taller towers. This does not even include television or microwave transmitter links or any of the other communications that are potentially interrupted.
If this is the cost of so little, what does that say of plans to have ten or fifty times as many wind turbines on the landscape? How much damage will that cause weather prediction, air traffic control, communications etc etc?
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September 1st, 2009 at 5:51 pm
Victor said:
This is utter nonsense. The carbon footprint of nuclear power is comparable to that of hydro power, and radiation detectors at the boundaries of nuclear plants cannot distinguish the plant’s emmissions against the natural background.
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September 2nd, 2009 at 1:12 pm
The one thing that I could see being an issue that would force the removal of a wind farm or denying it a building permit would be airport radar. I think television and even dopler radar would have to suffer, but airport radar is a safety issue that is taken seriously enough to actually make a difference.
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September 2nd, 2009 at 6:54 pm
Russ said:
Apparently you don’t understand that weather radar is important to aviation safety, and in some places, like Southern Fl, important to the general public as well. Note too that TV and radar are not the only users of spectrum.
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September 2nd, 2009 at 7:42 pm
DV82XL said:
I understand that. I just don’t think that the national weather service has the clout to get something as politically popular as a wind turbine moved. The only thing that I think would be potent enough to actually veto a wind turbine would be the FAA saying “Because of these turbines we can’t effectively track planes in this area” That might actually get it moved or taken down.
Notice that despite the problems that the dopler radar stations have, the turbines are still there.
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June 24th, 2010 at 8:48 pm
I have been searching for a decent set of plans to build a small wind turbine, I am sure that it would lessen our electricity costs. I know new ways of energy is what is in the close future.
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June 24th, 2010 at 9:04 pm
Mr. Wind Turbines For The Home said:
Be sure to run the numbers first: construction/materials cost and maintenance costs vs estimated energy return. You may be quite surprised by what you find.
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July 10th, 2010 at 5:45 pm
Looking for good credible up to date info regarding the effects of wind farms on radar. I live between 2 main radar facilities (air traffic control) and 15 miles from a nuclear plant. Plans are for 90 or so 410 ft turbines right in between and say 40 miles at best from radar on either direction. Nuclear Regulatory Commission response was,”Due to national security we cannot address your concerns.” Now I’m concerned!
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