Minty Wind Turbines
Energy is the leading contributor to global greenhouse gas emissions.
We do have renewable energy options, such as wind energy, but the reason these only account for 11% of energy production is they aren’t as reliable as fossil fuels. For example, in winter frost can form on wind turbine blades which creates drag, reducing their efficiency. Icing typical of the Guetsch Alpine Test Site reduces their wind turbines’ efficiency rate by up to 22%!
Icy weather also means that turbines must shut down so as to prevent damage. Even with these precautions, it only takes around 5 years for a wind turbine situated in a cold climate to break from excess frost.
The current solution to this problem is to spray turbines with chemical deicing agents. On top of being harmful to the environment, they must also be reapplied every time the temperature drops.
Reduced frost on wind turbines would result in more use of wind power because it would be more convenient, reliable, and live up to its environmentally friendly claim.
Biomimicry Time
The need to avoid frost and freezing isn’t something unique to humans. Or animals for that matter! Plants must stay where they are in all weather which means their protection needs to be attached to them!
They’ve developed all sorts of wacky adaptations from the lobelia’s shield of ice to the cabbage groundsel’s cell juice closure mechanism.
During my research I found that frost and cold protection strategies fell into three main buckets: nanostructures, physical barriers, and genetic mutations.
Nanostructures are tiny bumps and ridges on the surface of plants which make it difficult for ice crystals to grip and attach to organisms. Often they are also hydrophobic.
Plants that go with the physical barrier route keep their most important parts (like those used for reproduction) underneath or behind a thick physical barrier. This prevents the cold from penetrating and bursting their most vital cells’ walls.
Although this is most commonly found in animals, some plants have developed special genes that act as natural antifreeze and prevent them from changing states (and then bursting) when the temperature drops.
Mint Plants
Mint plants are very frost hardy due to their uneven surface. Their concave veins form a web over the entire leaf. No frost forms in these valleys (it evaporates because of a difference in vapor pressure) which is why it is advantageous to be so densely covered. The veins also prevent frost on the surface from spreading. Some ice crystals can still form on the ridges, but much less than without the valleys and they can be easily removed.
Lotus Plants
The cuticle (surface) of a lotus plant is made of wax crystals which jut out of the surface. This makes the surface look rough under a microscope and the surface superhydrophobic. It’s also what gives the plant its ability to self clean.
It can do this because water sticks to solids better than it does to air, so the trapped air beneath a water droplet makes it difficult to attach. It has little else to stick to, so the water attaches to itself, forming spheres. Then, with a little breeze or gravity, it just rolls right off!
The Solution
To prevent frosting over, wind turbine blades could be laser-engraved as they come out of the factory with the same microstructures as mint leaves. Then, they’d be coated with a waxy, hydrophobic substance like that of a lotus plant.
These two processes prevent frost from forming on the wind turbines blades enabling peak performance. This solution also improves the problem of climate change because it makes using wind power more efficient and desirable. Plus, by making the blades last longer, resources are conserved and toxic deicing agents are spared.
While this process won’t be able to change existing turbines, the number of wind turbines in use is expected to grow 13% by 2050 so it would still have a substantial impact.
This was an entry into the 2021 Biomimicry Youth Design Challenge and won the Design Cycle Award. You can learn more and explore other winners here.
