Wind turbines and windmills may look similar, and many people confuse the two terms, but in fact, they are two very different things.
A wind turbine converts wind energy directly into electricity through rotating blades connected to a generator. A windmill uses wind energy to perform mechanical work, such as grinding grain or pumping water through a system of gears and shafts.
This beginner's guide explains the differences (and similarities) between turbines and windmills in terms that anyone can understand.
Contents
The table below summarizes the key differences between windmills and wind turbines.
| Feature | Windmill | Wind Turbine |
|---|---|---|
| Primary Purpose | Mechanical Work (grinding Grain, Pumping Water, Sawing Wood) | Electricity Generation |
| Output | Mechanical Energy | Electrical Energy |
| Design | Traditional Design with Four Sails/blades, Often Made of Wood or Fabric | Modern Design with Aerodynamic Blades (usually 3), Typically Made of Composite Materials |
| Size | Generally Smaller, Usually 10-30 Meters in Height | Can Be Much Larger, Modern Utility-Scale Turbines Can Exceed 150 Meters in Height |
| Technology | Traditional Technology Using Gears, Shafts, and Millstones | Modern Technology Using Generators, Transformers, and Electronic Controls |
| Historical Context | Dates Back to Ancient Persia (7th Century Ad), Widely Used Before Electricity | Modern Invention Dating to Late 19th Century, with Significant Development Since the 1970s |
| Current Usage | Limited Practical Use Today, Mainly Preserved as Historical Landmarks | Widely Used for Commercial and Residential Electricity Generation |
| Efficiency | Lower Efficiency for Converting Wind Energy | Higher Efficiency with Modern Aerodynamic Designs |
Now let's look at wind turbines and windmills in more detail, to find out the different types, how they work and what they are used for.
A wind turbine is a device that converts the kinetic energy of wind into electrical energy.
Wind turbines are typically used in conjunction with other forms of renewable energy, such as solar panels, to create a more reliable and consistent source of green power.
A good domestic wind turbine can generate power for an individual house, boat, or RV. Large-scale wind farms generate renewable energy that can power thousands of homes.
Modern wind turbines work by using the kinetic energy of wind to spin a generator that produces electricity.
The curved blades of a wind turbine generate lift and a difference in air pressure on each side of the blade, which causes them to rotate.
The force of the wind turns the wind turbine blades around a central shaft, which is connected to a gearbox. The gearbox increases the speed of rotation and transfers the energy to a generator. The generator then generates electricity that can be used to power homes and businesses.
Wind turbines can be located offshore or onshore.
An onshore wind farm is typically located in rural areas where there is a consistent source of wind.
An offshore wind farm is located a few miles out at sea, where the wind blows at stronger and steadier speeds.
Wind farms are becoming increasingly common, as they offer a more efficient and environmentally friendly way to generate electricity than using fossil fuels such as coal or natural gas.
One wind turbine has the capacity to power as many as 940 US homes.
A windmill is a machine that converts the energy of the wind into rotational energy using vanes called sails or blades. Centuries ago, windmills were usually used to mill grain, pump water, or both.
The first windmills were developed in Persia and China more than 1,000 years ago. Windmills later spread to Europe, where they were used in agriculture.
By the 18th century, windmills were also being used in America to grind flour and transport water. In the late 19th century, windmills were used to generate electricity in Europe and America.
Historically, windmills were used for agricultural processing and water management before electricity became widely available.
In some regions such as the Netherlands, traditional windmills are still used for these purposes, though many have been replaced by electric motors.
Today, historic windmills also serve as cultural landmarks and tourist attractions, preserving traditional technology and architecture.
Windmills are classified according to the way their vanes are mounted on the main shaft. The three most common types of windmills are post mills, smock mills, and tower mills.
The sails of a windmill are angled so that they catch the wind blowing in from the side. The force of the wind turns the sails around the main shaft, which is connected to a large gear wheel.
The gearwheel turns a second, smaller gearwheel that is connected to the millstone. The millstone grinds grain into flour or meal.
Windmills and wind turbines share an obvious common factor - that they use blades to harness wind power. But there are several key differences between them.
The main difference between a wind turbine and a windmill is their purpose.
Wind turbine technology uses the wind to turn blades that spin a generator, which produces electricity. Windmills work by using the wind to turn blades that pump water or grind grain.
Wind turbines are usually much larger and higher than windmills, with thinner blades, and often operate together in larger installations. Windmills are typically smaller, but have thicker blades, and generally require less power to operate.
Wind turbines need to be located in areas with strong and consistent winds, such as on top of hills or in open fields. Windmills also only work when the wind blows, but they can only be located onshore.
Wind turbines are a relatively new technology, while windmills have been used for centuries.
So, while wind turbines and windmills both use blades to harness the power of the wind, they are designed and used in different ways.
Wind energy is a type of renewable energy that uses wind to produce electricity.
Wind energy is a clean, emission-free source of electricity, making it a very attractive option for those looking to reduce their carbon footprint.
Wind energy is the energy that comes from the wind. This can be harnessed using wind turbines, which convert the wind's energy into electricity.
Wind power is the term used to describe the amount of electricity that is generated by a wind turbine.
The name "windmill" is derived from the fact that these early machines were powered by the wind and were used to mill grains, wheat, or paper.
Wind power is generally recognized as one of the cleanest forms of renewable energy. But just like any other energy source, it isn't perfect.
Wind turbines and windmills are two very different technologies that are commonly (and incorrectly) confused.
They both use blades to convert wind power into clean energy, but turbines produce electricity, whereas windmills are used to directly produce mechanical energy.
These can have various applications, but the energy produced must be used locally to the windmill itself.
To find out more about whether a domestic wind turbine could help you reduce your energy bills, check out our guides on the cost and benefits of a wind turbine, and the correct way to calculate its mean power output.
And now, if you hear someone use the terms windmill and wind turbine incorrectly, you can put them right (politely of course!)
