Blade Types for Wind Turbine Users | The Complete Guide
Jul 12th 2022
Sometimes getting the most out of your wind turbine can come down to the finer details. Gains or losses in efficiency at the margins can add up, even for something as basic as the blade type for your wind turbine.
Aluminum or carbon-fiber? Three blades or eleven? And what difference does that zinc plating make? The possible configurations can feel a bit overwhelming.
What options are the best for you? Is there a way you can tweak your setup to better hit your independent power goals?
Our team has decades of experience experimenting with, designing, and testing all sorts of blade types for your wind turbine. We want to bring that knowledge to bear to help you become an informed wind power customer.
This guide is meant to help you see the benefits of different materials, shapes, and configurations and help take you from overwhelmed to empowered.
How Many Blades Does my Home Wind Turbine Need?
The simplest answer only asks further questions: it depends. Much of the information you’ll find online is focused on the benefits of the traditional three-blade turbine, but there’s a catch for residential wind power users.
There’s a lot of information out there when it comes industrial-scale wind turbines, but a lack of corresponding science for residential wind turbines.
Fortunately, we have a good deal of experience using with residential wind turbines—farmers in the rural west have been using wind as their primary energy source for nearly a century.
We know that a few of the concerns that limit commercial turbines to three blades are not a concern for residential turbines.
First and foremost among those is shipping weight. If you’ve ever seen a train rolling past with multiple cars loaded with individual turbine blades, you can imagine how inefficient the logistics of larger, more complex turbines would be.
The other major concern for large turbines is drag. Some drag can help keep the commercial turbine stable and safe, but too much drag harms the turbine’s overall efficiency.
When you read online that any turbine with more than three blades is a waste, remember that’s for industrial wind farms.
Residential turbines are smaller and lighter than commercial ones, which means that the cost difference of shipping a three or eleven blade turbine is negligible.
Plus, since drag is partly a function of size, the impact of adding more blades to a turbine is not an issue (up to a point).
Which leaves us with a somewhat harder question: what’s the difference when it comes to your home’s wind turbine?
These differences are small, but generally speaking, the more blades you have, the more stable your wind turbine is. On the other hand, a turbine with fewer blades will be more efficient when it comes to actually generating power.
Again, at the scale we’re talking about, these are not make-or-break variations. But if you’re having a hard time choosing between one model or the other, you can use these marginal differences to help you decide.
If you live in an area that’s prone to severe storms and unpredictably high wind, it may make more sense for you to install a 3 or 5 blade turbine or simply shortening the tower height.
In contrast, a 7, 9, or 11 blade turbine may be better suited to areas where wind is harder to come by. Of course, they’re not magic—consult our guide to make sure your area has enough wind in the first place to make wind power a sensible choice.
What is the Best Shape for Home Wind Turbine Blades?
Pretty much all residential wind turbines commercially available have a similar profile—for good reason. Following the same principle as aircraft (and bird) wings, the blade design is designed to sculpt the airflow over the blade.
Since the air coming off the blade is moving a bit faster than the air flowing into the blade, each blade is able to generate RPMs and power in its turn.
The pitch of your turbine blades—the angle of the blade’s windward edge—is a key factor in maximizing your turbine’s efficiency, especially at low windspeeds.
Too low of a pitch and the narrow blades won’t turn in normal wind, too high and the effects of drag are maximized, severely curtailing efficiency.
We spend a lot of time crafting and optimizing the pitch of our turbines to sit in the sweet spot: just enough to perform in lower-wind condition.
Some of our blades also feature a gull-wing-style tip. This helps increase stability and decrease the operating noise of the turbine.
How Does Blade Material & Finish Affect Wind Turbines?
Our blades are made from two different materials: aluminum and carbon fiber composite.
Over the years, we’ve crafted our aluminum blades to be ultra-resilient and much quieter than other aluminum blades.
Carbon fiber is ultra-strong and lightweight, making the wind turbine blades better able to withstand damage from storms and debris. If you live in an area where a storm can arise quickly, you know how quickly things can get bad.
When the sun comes out, carbon fiber still has an important advantage. Namely, that carbon fiber is resistant to damage from UV rays, even over the course of decades.
We believe that the most important choice is switching to wind power in the first place. The type of turbine you get, the number of blades, all of these other things do make a difference in helping you maximize your system.
First, claim your energy independence. Then you can worry about the details.
How many blades are best for a wind turbine?
Put simply: more blades are better for low winds, while fewer blades means more efficiency. For residential wind turbines, these differences are minor. Industrial wind turbines are almost always three blades to balance these concerns.
What is the pitch of a wind turbine blade?
A turbine blade’s pitch is the angle of said blade’s windward edge. The degree of pitch can affect the turbine’s performance by either not generating flow over the blade (too narrow) or creating too much drag (too wide).
Can a wind turbine spin too fast?
Yes. In severe weather, high winds can create dangerous situations where turbines become unstable. With a residential turbine, the smaller size means less risk, but it can still be dangerous to let a small turbine spin out of control. A small wind turbine should be kept under a load or lowered to prevent items from striking the unit.