It should be noted, however, that most modern windmills are actually referred to as wind turbines to distinguish them from their older cousins. This guide will teach you how to build a wind turbine; we will use the term “windmill” for the sake of convenience.
The History of Windmills
Windmills date back to sometime between 500 and 900 A.D. when the Persians first invented them as a way of grinding grain. The power of the wind had been known to people for years, as they had been using sails to catch the wind and power their sailing ships when the Persians decided to modify them for a different use. They used vertical type sails connected to a spinning shaft which was connected to a pump and a grind-stone. This allowed them to harness the power of the wind to grind their corn and grain.
Windmills were not a part of European culture for over another century or longer. They looked very different than their Persian predecessors; so different, in fact, that it is speculated that they were both developed independently of the other. The early European windmills are often referred to as having a post-mill structure, which is so-called because the main structure of the windmill sits on a wooden post that allows the structure to face in the direction of the wind, no matter which direction the wind happened to be blowing. This was achieved by a horizontal beam attached to the structure that allowed the entire device to be turned. The whole thing used gears and cogs to transfer the power from the wind.
China developed windmills around 1219 A.D., and the Dutch built them in the 1300s. These Dutch windmills were a whole new type of windmills, due to the development of new sails that increased their efficiency. These sails were so effective, that very little about them was changed or altered for the next five hundred years.
In the 1800s, the United States created a new type of windmill which utilized a small rotor on top of a steel structure. These steel structures first used wooden blades, but they switched them to steel quite soon afterwards. They were popular, especially in the West, because they were used as water pumps. Eventually, the rotors were made to look more like the propellers on airplanes. They were connected to generators and used to power the electricity in small cities and towns. The popularity of windmills persisted until the 1930s with the invention of electricity.
Benefits of Using Windmills for Energy
The main benefit of windmills is that they produce energy by using the wind, which is, of course, free. Wind does not have to be mined; it does not have to be transported to facilities and converted into oil; and more importantly, it is sustainable.
There are many other benefits, as well. Windmills can generate energy that does not emit any types of contaminants or airborne pollutants into the nearby waters, winds, or lands, which means the use of windmills does not lead to awful and earth-damaging things like acid rain or climate change. Furthermore, windmills can be built and taken care of by private citizens, which means they can generate their own energy and electricity without having to pay for expensive electricity bills.
Uses for Windmills in Today’s Society
Many of the uses for windmills today are the same uses that they had when they were first invented over a thousand years ago. In addition to being a renewable source of energy and electricity, which was mentioned above, windmills can also be used to pump water, to aerate ponds, and to grind corn, meal, or many other things.
Windmills: What to Consider First
Before you begin a project to build a windmill, it’s important to understand a few terms. You should also outline your purpose for building the windmill. If you’re only interested in how to build a windmill as a DIY proof of concept project, you can go ahead and skip to step 6.
Windmills are rated by their “capacity factor”. We can determine it by taking the average amount of power that the windmill generates and dividing it by the maximum (or peak) amount of power it can generate. Therefore, a windmill which can produce a maximum of 100 watts of power but averages 50 watts will have a capacity factor of 50%.
The reason why the capacity factor is so important is that the size, design, and materials used to build the windmill must be calculated by its capacity factor, sometimes referred to as its load factor. Effectively, you’ll be building your windmill based on its capacity factor rather than its maximum (peak) factor. Of course, how strong the wind blows and other factors will determine how much energy your windmill actually produce. Nonetheless, the capacity factor is a good way to estimate how much energy your windmill will be delivering.
Last but definitely not least, windmills are only designed to produce electricity and not store it. As you’ll see when learning how to build a windmill, if the wind stops blowing, your windmill won’t produce any power at all. In order to effectively smooth out variations in energy production, you will need to store the electricity in the form of batteries.
How to Build a Windmill
Step 1 – Determine the wind speed
Before researching how to build a windmill, you’ll need to determine the average wind speed for the area that you’re going to install your windmill. Most of the time, you will want a minimum of 7-10 miles per hour (11-16 kph).
Depending on where you live, you may be able to find this information online (search for wind maps) but you can always use an anemometer to measure wind speeds at regular intervals. Remember that seasonal changes in windspeed can strongly affect how to build a windmill.
Step 2 – Check local codes
Every locality has their own rules and regulations about where and how to build windmills. Some jurisdictions impose limits on windmill height, how far the windmill will stand from an occupied structure, or even how close the windmill is to an adjacent property. It’s also a good idea to discuss your windmill plans with your neighbors if you’re building something big.
Step 3 – Evaluate the area
Learning how to build a windmill is relatively easy. Still, you need to make sure that there’s enough space around the windmill to use it properly. Most experts recommend at least half an acre of free space around smaller windmills. Allow a full acre for full-size windmills. Look for any trees or buildings that might interrupt the airflow reaching your windmill as well.
Step 4 – Choose your blades
Effectively, you have two options when it comes to building a windmill. You can buy pre-made blades or make the extra effort to building them yourself. If you’re not completely sure what you’re doing, it’s usually best to buy pre-made blades. You can always make the shaft and other components of the windmill yourself to be used with pre-made blades if you still want an authentic hands-on experience.
The blades of the windmill are what catch the wind and use it to turn it on its axis and generate power. The blades need to be carefully shaped and sculpted in order to get the most power from the wind. Almost all windmills use an odd number of blades for stability reasons. Three blades are the most common option as five or more blades cause the windmill to spin more slowly.
Step 5 – Pick a generator
The wind spinning the blades creates a torque (rotational energy), but you’ll need a generator to convert this into electricity. Most windmill generators deliver DC (direct current) that will have to be inverted to AC (alternating current) if you plan on using the electricity in your home or to power devices like laptops, lights, and televisions.
Much as with the windmill blades, you can choose to build your own generator or spend more for a manufactured generator. If you buy a generator, make sure it can handle low rotation speeds (RPM measured in the hundreds, not thousands). Some people like to repurpose car alternators as their windmill generator. However, this is not usually recommended, as alternators are designed to spin at several thousand RPM. They may not work if the wind speed is too low.
Step 6 – Place the base
Once you have your plan in place, it’s time to start building the windmill. The central verticle axis is known as the spindle, and you’ll need to secure this spindle. Most windmills use a spindle plate, a heavy piece of steel that is welded to the spindle.
Step 7 – Assemble the windmill
Carefully assemble all the components of the windmill; start with the hub, spoke flange, spokes, magnet rotor, spacers, nacelle, wiring, electrical components, and finally the blades.
Frequently Asked Questions About Windmill Energy
There are many different frequently asked questions about wind energy. Here are five of the most commonly asked ones:
1. Do windmills kill or injure flying animals?
It is a sad fact that when people make progress in the world, it often comes at the expense of the animal life in the area. However, even though birds and bats are sometimes killed when they fly into windmills, the rate at which this happens is incredibly low. Less than .02% of the population of birds in an area are killed in accidents with windmills, and with new advancements in windmills happening all the time, this number is becoming lower and lower.
2. What impact do windmills and wind energy have on human health?
Windmills have absolutely no negative impacts on human health. The only thing about windmills that might even possibly aggravate humans is the sound of the wind turbines turning. Although this sound may be irritating, it has no negative effects on human hearing and most people claim to stop noticing it after a short while.
3. How much wind energy does the U.S. utilize?
About six percent of all the energy in the U.S. comes from windmills. However, in Iowa and South Dakota, wind energy makes up thirty percent of all energy usage.
4. Can wind turbines be roof-mounted?
It has been done in the past, but no, mounting windmills to the roof of a building is not recommended.
5. Where can I learn more about wind energy?
You can visit Energy.gov to find out more information on windmills and wind energy.
Whether you decide to manufacture and assemble all parts of the windmill yourself or use some pre-made parts, learning how to build a windmill is a great introduction to using and understanding sustainable forms of energy. A quality windmill is virtually silent and extremely safe. It can produce substantial quantities of energy when mounted in the right location. Let us know how your project came out!