In our modern energy economy, wind turbines are finding a place for large-scale wind energy generation. These structures are of necessity very tall (hundreds of feet in the air) with great wind-swept blades that can be deadly for birds, How many flying creatures have been injured or killed because of wind turbines today, and are projected into the future?
Are bird kills a criterion by which a wind turbine installation is evaluated? Do good wind speeds correspond to high bird migration activity, making this a condition that promotes bird kills?
This bird kill situation begs the questions:
* Could warning devices be built into turbine blades or support structures that would warn birds?
* Could these warning devices be strategically located near existing wind machines? How about a large area wind farm?
* Might there be a way to alert wind machines from a distance, to activate their warning mechanisms?
Hopefully, this design challenge will get those creative minds in your classroom asking questions and synthesizing interesting options and solutions.
Starting the Problem Analysis
It's time to get those students interested in birds and related creatures, and that begins with the internet and maybe the biology teachers at school, How high do birds tend to fly on regular or migratory treks? How would a bird perceive a rotating blade in space? Would such a spinning blade confuse their senses?
It's been said that ground animals have trouble judging the speed of moving vehicles and thus get killed on the roads. Do birds have such a problem in the air? Just how high are wind machines today and the even larger machines being planned? Is there a certain family of wind machines that are more lethal to bird populations? Is there a safe design height for wind machines?
Can birds be warned acoustically? Has anyone tried to do this before? Bats can communicate and locate objects using a bird-type radar--might this ability double as a warning signal? Are wind turbine designers and manufacturers concerned with this bird threat? Have they built and tried warning systems or perhaps some other kind of warning/avoidance system? Have environmental groups applied pressure to designers and installers to address the concern? Is there active research now underway at universities or other animal safety organizations to address the problem?
What types of warning signal might be considered either for location on the wind machine support structure or on its spinning blades--such as acoustic emissions, flashing lights, or something else that might be considered? Does this warning signal work for a broad spectrum of flying creatures or vary greatly among species? Would a cluster of warning signals be employed?
How much would these warning devices cost and how could they be attached for long-life deployment? If installed on the spinning blades, would they affect aerodynamic performance of the machine and result in loss of power and damaging vibration to the machine?
Can changing the color of the wind machine structure and blades alter a bird's perception of the machine itself and prompt it to avoid the potentially dangerous situation? Is there another option for warning birds--maybe another portion of the electromagnetic spectrum to which birds may respond, sensing a warning signal?
What about varying the spinning rate of the turbine as birds are detected approaching the machine as a viable way to avoid bird kills? This raises other questions, like how can humans detect when birds are approaching? How do humans, or their designed equipment, communicate with the wind turbines? Where does one locate the bird-detection equipment?
Having delved deeply into wind machine-induced bird kills, how do your students think wind machines ought to be retrofitted to reduce bird kills? Should wind machines simply be designed differently? Encourage out-of-the-box thinking!
Harry T. Roman is a retired engineer/ inventor and author of technology education/ STEM books, math card games, and teacher resource materials, He can be reached at email@example.com.