Wind turbines frequently kill birds, and efforts are being made to build new models that reduce bird mortality.
That raises the question whether wind farms might also generate enough turbulence to endanger light aircraft?
Examining the risks of wind farms may pose for ultra-light aircraft, researchers at the Fraunhofer Institute for Wind Energy and Energy System (Oldenburg, Germany) report that they have developed a simulation tool that can compute how power plants influence aircraft at various wind speeds and wind directions.
Researchers said the simulation can calculate how much turbulence wind farms generate, how they can alter wind speed and what influence these factors have on airplanes. After conducting simulations under various scenarios, Fraunhofer's Bernhard Stoevesandt said "we simulated various wind directions, two different wind speeds and five different flight trajectories in which the plane is under the rotor’s sphere of influence for various lengths of time."
The German researchers created a computer model of the ground and a wind profile of the surrounding area where a wind farm is meant to be built. The model calculated how turbines alter wind conditions and create turbulence on a grid.
"The true skill is in the creation of the grid because the points on the grid where the computer makes the individual calculations must lie at exactly the right places,” said Stoevesandt, specifying that the software must calculate the prevailing currents within several million grid cells that mutually influence each other. Other challenges include accurately depicting the trail – the turbulence and the change in wind speed behind the rotor – and assessing how this might affect a small aircraft flying near a wind farm.
A Fraunhofer simulation demonstrates the turbulence generated by wind turbines. The red area shows heavy turbulence, which is common near wind farms.
To validate the simulations, Stoevesandt said the trail from actual wind energy plants was measured at individual points behind the rotor, then the measurements compared with the simulations.
The researchers examined the effects of wind farms within an approximately 1,500 meter perimeter and an altitude of up to 500 meters.
The simulations also illustrate something any any good pilot should know: Steer clear of large obstacles on the ground.
I personally do not know who and what to believe anymore. There is just too much public money involved in green energy R&D. It's inviting corruption at an alarming proportion in science and engineering :-(
Corruption risk always exists...but much serious problem in public money R&D is waste, in my mind large portion of teh money awarded is typically wasted...typical application grants are checked carefully when you apply but after the fact nobody bothers to check what you have done with the money
More concerning are the effects of wind turbines on weather and soil moisture. Google "wind turbine turbulence soil moisture" and you will find a slew of articles, both simulation and measurements, that the additional turbulance near the ground surface level causes moisture to evaporate and dew not to form on the ground.
Add this to the location of the wind farms, at least in California, which reduce the flow of air from the cooler and moister sea to inland hot and dry areas, I am concerned about the potential for negative climatic effects.
The bird kill problem (google "wind turbine bird kill"), if it were from any other "less green" energy source would be quickly addressed.
Personally I'm hoping for liquid thorium fluoride reactors (lftr) development - these can be used to consume the waste we are keeping in so many cooling pools and are afraid to bury - they produce much less waste with much shorter half lives by avoiding creating the long lived actinide series elements. This is probably why our early ltfr reactor was killed in the cold war - it made no plutonium for weapons.
LTFR reactors can not melt down - they are already liquid! They are hot enough to efficiently generate hydrogen without electrolysis and have good efficiency even without using water cooling (though better efficiency with a cool sink). They are operated at atmospheric pressure, with liquid salt cooling loops, so radioactive steam leaks are avoided.
Thorium is present at about 10 ppm in most soil, and North America is one of the large reserves. Using these reactors to consume the stock of waste fuel rods rather than burying them would probably be less expensive than burying them and the waste that remains mostly decays within 60 years and is to a background level in 300 years rather than 10,000 years.
Appreciate that but the stakes are very high if we get this wrong. I am rather in favour of an international Manhattan-style project to develop the next big sustainable energy technology, a project that is void of commercial interests and whose outcomes are free and open for everyone.
I dream of course as there are too many powerful vested interests....
All reactor design requires government approval. Several companies are working toward LTFR, as are China and India, among others. We had a working model in the 60's. Main obstruction is likely lobbying - the fuel for a 1GW plant is approximately $10k instead of $10M - at least that is my guess. India is looking at a sub-critical design using an accelerator as a neutron sourceinstead of a critical mass.
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