From the University of Delaware a press release I just can’t stop laughing about. Of course, they have no real-world tests of this claim, only “their sophisticated climate-weather model”. No numbers were given on turbine “mortality”, so one wonders how many would survive.
Offshore wind turbines could weaken hurricanes, reduce storm surge
Wind turbines placed in the ocean to generate electricity may have another major benefit: weakening hurricanes before the storms make landfall.
New research by the University of Delaware and Stanford University shows that an army of offshore wind turbines could reduce hurricanes’ wind speeds, wave heights and flood-causing storm surge.
The findings, published online this week in Nature Climate Change, demonstrate for the first time that wind turbines can buffer damage to coastal cities during hurricanes.
“The little turbines can fight back the beast,” said study co-author Cristina Archer, associate professor in the University of Delaware’s College of Earth, Ocean, and Environment.
Archer and Stanford’s Mark Jacobson previously calculated the global potential for wind power, taking into account that as turbines are generating electricity, they are also siphoning off some energy from the atmosphere. They found that there is more than enough wind to support worldwide energy demands with a negligible effect on the overall climate.
In the new study, the researchers took a closer look at how the turbines’ wind extraction might affect hurricanes. Unlike normal weather patterns that make up global climate over the long term, hurricanes are unusual, isolated events that behave very differently. Thus, the authors hypothesized that a hurricane might be more affected by wind turbines than are normal winds.
“Hurricanes are a different animal,” Archer said.
Using their sophisticated climate-weather model, the researchers simulated hurricanes Katrina, Isaac and Sandy to examine what would happen if large wind farms, with tens of thousands of turbines, had been in the storms’ paths.
They found that, as the hurricane approached, the wind farm would remove energy from the storm’s edge and slow down the fast-moving winds. The lower wind speeds at the hurricane’s perimeter would gradually trickle inwards toward the eye of the storm. “There is a feedback into the hurricane that is really fascinating to examine,” said Archer, an expert in both meteorology and engineering.
The highest reductions in wind speed were by up to 87 mph for Hurricane Sandy and 92 mph for Hurricane Katrina.
According to the computer model, the reduced winds would in turn lower the height of ocean waves, reducing the winds that push water toward the coast as storm surge. The wind farm decreased storm surge — a key cause of hurricane flooding — by up to 34 percent for Hurricane Sandy and 79 percent for Hurricane Katrina.
While the wind farms would not completely dissipate a hurricane, the milder winds would also prevent the turbines from being damaged. Turbines are designed to keep spinning up to a certain wind speed, above which the blades lock and feather into a protective position. The study showed that wind farms would slow wind speeds so that they would not reach that threshold.
The study suggests that offshore wind farms would serve two important purposes: prevent significant damage to cities during hurricanes and produce clean energy year-round in normal conditions as well as hurricane-like conditions. This makes offshore wind farms an alterative protective measure to seawalls, which only serve one purpose and do not generate energy.
Jacobson and study co-author Willett Kempton, professor in UD’s College of Earth, Ocean and Environment, weighed the costs and benefits of offshore wind farms as storm protection.
The net cost of offshore wind farms was found to be less than the net cost of generating electricity with fossil fuels. The calculations take into account savings from avoiding costs related to health issues, climate change and hurricane damage, and assume a mature offshore wind industry. In initial costs, it would be less expensive to build seawalls, but those would not reduce wind damage, would not produce electricity and would not avoid those other costs — thus the net cost of offshore wind would be less.
The study used very large wind farms, with tens of thousands of turbines, much larger than commercial wind farms today. However, sensitivity tests suggested benefits even for smaller numbers of turbines.
“This is a paradigm shift,” Kempton said. “We always think about hurricanes and wind turbines as incompatible. But we find that in large arrays, wind turbines have some ability to protect both themselves and coastal communities, from the strongest winds.”
“This is a totally different way to think about the interaction of the atmosphere and wind turbines,” Archer said. “We could actually take advantage of these interactions to protect coastal communities.”
The paper, titled “Taming Hurricanes with Arrays of Offshore Wind Turbines,” appears online on Feb. 26 in Nature Climate Change and will be published in print in March.
“The videos of the initial collapse will be entertaining.”
The shrapnel coming on shore at 90+ mph won’t be very entertaining.
Carl said:
So they’re claiming a modeled drop in “Hurricane” Sandy’s wind speed of 78 to 87 MPH. I found NOAA data online that clocked Tropical Storm Sandy at 49 MPH sustained with gusts up to 73 MPH at JFK. So… 49 minus 87 equals…
The sustained wind speeds may have been 49 mph on land, but they aren’t taking about putting the wind farm on land. The wind farm would be offshore where the wind speeds were higher.
Frankly,I’m skeptical of the 78 mph reduction, but it isn’t as absurd as you suggest. The sustained wind speeds were 105 mph on 25 October.
http://www.nhc.noaa.gov/archive/2012/al18/al182012.public.012.shtml?
Again, I doubt the modeled reduction, and wonder if someone garbled the reading mistaking a reduction from 105 to 78 as a reduction of 78 mph.
bobl says:
… sandy wasn’t a hurricane it was just a big storm a lot like the ones we get in the north west here in Oz. ,/i>
Sandy was a hurricane, you can look it up. Many people mistakenly think it was a hurricane when it made landfall in the US; they are wrong. However, the people in Jamaica and Cuba think it was a hurricane when it hit land. There are places other than the US.
Those looking for further amusement (or evidence concerning the paper’s author’s sense of humor, sanity or lack thereof) can obtained a pdf copy of the paper from: http://www.stanford.edu/group/efmh/jacobson/Articles/I/WindHurricane/HurricTurbPaperNatCC.pdf
A 7.58 MW turbine has a hub that is 130 m above the surface and a rotor that is 90 m in diameter. The author’s plan calls for one every 0.7 km2, so they would be spaced about 1 km apart. (For comparison, the towers of the Verrazano Narrows Bridge are about 210 m high and 1 km apart. So they are proposing an array of towers with height and spacing similar to the Verrazano Narrows Bridge (or the Golden Gate Bridge with an extra tower in the middle.) With rotors that sweep out about 10% of the area between them… Up to half a million of them. That’s a serious windbreak.
An efficient turbine can abstract about 1/2 of the power in the wind passing through it. That will reduce the velocity of the wind passing thorough the rotor by the cube root of 1/2. If the same parcel of air passes through three turbines, its velocity will have been cut in half and its power (to cause damage) to an 1/8. Since only about 10% of the air up to 200 m above the ground passes through the blades, one would need thirty rows of turbines to reduce wind speed by 50%. But 30 rows of turbines 1000 km long represents only about 10% of the number of turbines in a typical proposed array. This back-of-the-envelop calculation suggests that a large array has potential to moderate a hurricane.
While RGB is correct in pointing out that hurricanes release almost a PW of power, almost all of this energy is latent heat. The wind power in a hurricane is only 1.5 TW, comparable to the power the authors hope to extract with turbines. So two lines of evidence suggest the possibility that hurricanes could be moderated by such an array. This could allow the array to survive. (For the wind power in hurricanes, see: http://www.aoml.noaa.gov/hrd/tcfaq/D7.html, but their value for world-wide electricity production appear to be too low by a factor of 10X).
Sorry Andy, these aren’t climate models. Betz Law limits the maximum power a rotor can extract from the wind. The rotor on a turbine is analogous to an airplane wing and we’ve had reasonable models and practical experience working with these objects for decades. The power entering a rotor that is not converted to electricity or heat (friction) remains in the exiting wind, which is turbulent and used inefficiently by downwind turbines. We also have models that predicted how much power would be obtained from off-shore wind farms that were later built. The power entering a rotor that is not converted to electricity or heat (friction) remains in the exiting wind, which is turbulent and used inefficiently by downwind turbines.
Surprisingly, the real impracticality of the project comes from non-science issues. With an installed cost of perhaps $30M for each turbine, the cost for the largest array would be $15T (comparable to annual US GDP or national debt). The total cost of the largest construction project in history, the Panama Canal, was equivalent to only 1% of the US GDP at the time. To complete a large array, we would need to build and erect about 50 turbines/day for a two decades. By the time we finished, the oldest turbines would need to be replaced! In theory, the cost of the project might be recovered from selling the electricity it produced. That could be 5% of GDP, just to pay for electricity that won’t be available when the wind doesn’t blow. Given the density of the array, many turbines will be downwind of other turbines and receive less power. If the proposed array of turbines can cut wind speed in half and harvest 7/8 of wind power from hurricanes, many turbines will be operating in an extremely inefficient environment for the other 99% of the year.
On the few days per year when a hurricane IS moving through this array of turbines, another problem will arise: What to do with 1+ TW of electricity – when the whole country uses an average of 2-3 TW? The rotors can’t be feathered – the hurricane will not be moderated and the array could suffer severe damage. A high-capacity grid would be needed for a few days to spread this power across the entire country without blowing circuits. Most other generators will be running in reserve mode (usually emitting CO2), so they are prepared take over as the hurricane dies out.
[Are all of the above paragraphs your own claims, or have you quoted any one else? Mod]
All this and yet they have no impact on natural ecosystems or human beings………..honest!
Unintended consequence was mentioned several times on the blog.
Here is an example.
Wouldn’t this still count as climate change?
http://web.mit.edu/newsoffice/2010/climate-wind-0312.html
Hurricanes are a natural feature of the system with the purpose of restoring thermodynamic equilibrium. Perhaps instead of preventing or weakening their existence, we should adapt to this known natural and necessary mechanical process.
To each a purpose, and everything with a purpose. Leave the windmills to do what they do best, puree our fine flying friends.
Enjoy the product of a left-leaning academia.
Oh rats! Crispin beat me to it. I was going to point out that the obvious solution is to run the windmills in reverse, and simply blow the hurricane out to sea. But Crispin already did:
Ah well, great minds think alike.
/Mr Lynn
Makes you wonder whether these yo-yos who put out this “study” have ever even seen a wind turbine.
Hurricane-force winds will chew up wind turbine blades like so much tissue paper.
So what cartoon and episode is this going to play in. Maybe I’ll watch it and see how the super environmental hero saves the world again. This isn’t quite as good as the mirrors in space to reflect the suns rays away from earth to counteract global warming though.
I thought the reason for the windmills was because burning fuel changes the weather, and we’re not supposed to change the weather. So why isn’t it bad when windmills change the weather?
Thinkbeforeyoulaugh says:
February 27, 2014 at 3:59 pm
“A 7.58 MW turbine has a hub that is 130 m above the surface and a rotor that is 90 m in diameter. The author’s plan calls for one every 0.7 km2, so they would be spaced about 1 km apart.”
“An efficient turbine can abstract about 1/2 of the power in the wind passing through it. That will reduce the velocity of the wind passing thorough the rotor by the cube root of 1/2. If the same parcel of air passes through three turbines, its velocity will have been cut in half and its power (to cause damage) to an 1/8. Since only about 10% of the air up to 200 m above the ground passes through the blades, one would need thirty rows of turbines to reduce wind speed by 50%. But 30 rows of turbines 1000 km long represents only about 10% of the number of turbines in a typical proposed array. This back-of-the-envelop calculation suggests that a large array has potential to moderate a hurricane.”
Right. The height of the blade at the top is 200 m (allowing the bottoms of the blades to be 25 m above sea level) and the circle of the blades is 90 m. As the turbines are about 1 km apart, a row will only intercept about 10% of the low level air flow – ignoring the area outside the circle but in the square. The troposphere extends a fair way up – about 17 km near the equator, and strong hurricanes extend into it. 200 m is only about 1 – 2% of the height of a typical height of a hurricane, so the surface based windmills would only intercept about 2% of the vertical field. This means that the large array mentioned could be only likely to capture about 10% times 2% = 0.2% of the energy of the hurricane.
On this basis, the energy needed to be transmitted ashore is far below the estimates given by many people, above, but still damaging. And as the wind farm is in the region of strongest winds, still liable to the maximum damage.
Somehow I can only think that the vision of billions of Statues of King Canute – or perhaps of Michael Mann – is the only way to tame hurricanes. Thank you, jorgekafkazar , for the suggestion.
If this turns out to be a success we can then put thousands of windmills along the U.S./Canadian border to blow the Polar Vortex back to the North Pole. The cost will be offset by the savings of not having to supply the energy to heat all buildings in the northern U.S.
On a more serious note, since dry air is the death of hurricanes perhaps it would be better to put thousands of dehumidifiers all over the oceans to dry out the air. We could pipe the extracted water to holding tanks in areas known for droughts. ( Ok, that really wasn’t a more serious note).
Crispin in Waterloo says:
February 27, 2014 at 8:44 am
Sorry, Crispin, I didn’t notice you had already made the suggestion.
Sooo…….
Man causes “climate change”. That’s bad.
Man changes “climate change”. That’s good.
I’m not sure if I “got it” or I’ve “been had”.
Off shore wind farm + hurricane = undersea wind farm…
Ignorant, Arrogant, and Decadent.
The slogan that fits best.
Given that turbines are shut down at about Beaufort scale 7, how is this hypothesis going to work ?
I’m all for oceans full of wind farms for as long as none of it’s publicly funded, and there are no public bailouts, guarantees or clean-ups of any kind, if it tends to collapse through the event-horizon of a stupidity-hole.
Words fail me (almost) !!
Instead of sitting in air-conditioned offices playing doomsday arcade games on computers with badly written software, these ‘scientists’ ( and I use the word loosely), should get out & experience a force 9 in a trawler, join some storm chasers & then do a basic math’s course. Then they could estimate the carbon cost of “of tens of thousands of turbines” that like King Canute will achieved nothing.
Natures does what nature does…live with it…or perish.
If you say had two of these wind farms in different locations.
and used the power from one to power the other and visa versa.
you could move the storm around.
Just as silly idea?
I MUST spend more time prospecting. Once I find that unobtanium deposit, I am going to be sooo rich supplying unobtanium for hurricane farms. I think I will get a red and a blue Ferrari…
There are only two things that we know for a fact will stop hurricanes:
Cold water and huge forested areas.
I say we add another 300 miles of forested plains with man made water features completely around the Florida coastline!
Ok…intuitively this seems logical that wind turbines would take some of the energy from a storm. I guess beach chairs do the same thing for tsunamis.
rbravery says:
February 27, 2014 at 11:29 pm
Off shore wind farm + hurricane = undersea wind farm…
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You are mistaken. Off shore wind farm + hurricane = hurricane + on shore shrapnel.