Different Types of Wind Turbines You Should Know
 Topic: different types of wind turbines |  Read Time: 7 mins |
 Landowner type:Independent landowners | Institutional landowners |  Energy: Onshore wind |
26th July 2024In this ultimate guide on the different types of wind turbines, I’ll uncover everything you need to know about horizontal-axis, vertical-axis and residential turbines.
The first wind turbine appeared in July 1887 in Scotland, but we’ve come a long way since then. These days, the largest onshore turbines reach approximately 443 feet tall (135 m), showing just how immense these structures can be.
But are all turbines built the same? And how many kinds are there?
In this article, not only will I run through the two types of wind turbine, but I’ll also discuss their respective pros and cons. I’ll even cover the difference between onshore and offshore turbines.
What Are the Different Types of Wind Turbines?
There are two different types – horizontal axis and vertical axis turbines. Here, I explore what distinguishes these turbines from one another (and which is most suitable for your project).
Horizontal axis
When you hear the words ‘wind turbine’, you think about horizontal axis (HAWT) turbines, which make up the vast majority of utility-scale turbines. These turbines resemble windmills and are typically on the large side. The grandest HAWTs can be as high as multi-storey buildings.
The blades, shaft and generator are all at the top of the turbine, with the blades pointing directly toward the wind. You’ll also spot a nacelle on the turbine, which houses its more sensitive parts and shields them from damage.
Let’s take a closer look at the general structure of a horizontal-axis turbine to give you context about each part.
As you can see, the blades are shaped aerodynamically and attached to a horizontal, flat shaft. To be maximally efficient, the rotor plane needs to maintain a 180-degree angle with the direction of the wind.
For this reason, HAWTs are built with a wind vane and yaw system that keeps the turbine facing an optimal direction. Most horizontal axis turbines also feature brake systems to halt the blades if wind speeds get high enough to potentially damage the turbine mechanisms.
A typical HAWT turbine installation can generate anywhere from 2 to 8 megawatts (MW) depending on its size. Because they’re so much more common than vertical axis turbines, HAWTs comprised approximately 97.3 per cent of global wind power capacity as of 2022.
| Advantages |
| The blades of horizontal axis turbines are perpendicular to the wind. So, they typically generate more electricity than other types of wind turbine. |
| They’re highly efficient and less expensive than vertical-axis turbines. |
| They are usually very reliable and have a high capacity (though this always relies on wind speeds in the area). |
| The blades’ rotational speed is usually high and consistent, making them often more profitable than other turbines. |
| The blades can tilt the rotor if a storm is approaching. |
| You can bend the angle of the blades using the internal gearbox, giving you the best angle possible for harnessing wind. |
| Disadvantages |
| They can operate under less varied conditions than vertical-axis turbines and need to shut down when wind speeds are too high. In short, they’re more vulnerable than different types of wind turbine. |
| The size of the structures is advantageous when it comes to capturing wind energy, but it comes with maintenance issues. Because the generators are tucked inside the nacelle, they take longer to fix if a problem arises because maintenance workers need to mount the turbines. And the turbine will need to be shut down while any work is carried out. |
| The turbine requires heavy support for the blades at the base, meaning large cranes will be on a landowner’s property during construction. |
| They’re typically noisier than vertical-axis turbines. |
| They pose a risk to birds and bats, as they can collide with the spinning blades. |
Vertical axis
Vertical-axis turbines (VAWTs) are slightly more complex than horizontal-axis turbines and far less common.
Their unique blades are perpendicular to the ground instead of horizontal (hence the name) and are usually found in residential settings. They tend to produce less power than horizontal turbines and are categorised into several different models:
- Savonius: These have different blade shapes and different drive shafts
- Darrieus: Curved blades that rotate on their axis
- Mixed turbines: A mix of the previous two models that combine elements of each
- Giromill: Horizontal arms that join the vertical blades to the shaft
The Darrieus is the most common vertical-axis wind turbine, named after the French engineer Georges Darrieus, who patented the design in 1931.
The blades’ curvature allows them to be stressed at high rotational speeds, with the torque set at a high angle. This means the torque is always near the maximum possible output, creating more power.
In terms of size, some of these vertical axis turbines are around 100 feet tall and 50 feet wide. So, while they’re not typically as large as HAWTs, they’re still relatively big.
| Advantages |
| They can maintain their rotation ability in turbulent weather and low wind speeds. |
| VAWTs are omnidirectional and can function in any direction, so they don’t need to be facing the direction of the wind to operate. |
| They’re usually easier to install and maintain than HAWTs, as the turbine generator is at the turbine’s base (not in a nacelle). |
| The blades don’t stretch as far as horizontal blades, meaning you can fit more turbines in the same area. According to the Institution of Mechanical Engineers, they’re 10 times shorter than HAWTs, and you can cluster them into arrays more easily. This can even create light turbulence between turbines, allowing them to help each other. |
| The design is easy to scale, and VAWTs’ smaller sizes can make them more suitable for urban areas. |
| Many people believe they have a better visual flow and look than horizontal turbines. |
| Disadvantages |
| Efficiency is generally lower because of air drag. VAWTs also tend to sit lower than HAWTs. This means they’re less productive (because wind speeds tend to be stronger as you go higher up). |
| VAWTs are less common than HAWTs, making it tougher to find maintenance crews, materials and solutions if something needs to be fixed. |
| They’re generally cheaper to produce than vertical-axis turbines. |
| These turbines feature lower-speed blades, making them less of a threat to wildlife. |
| They are more transportable than HAWTs, as the materials are typically lighter. |
Onshore vs Offshore Wind Turbines
Onshore wind turbines
These turbines are located on land and driven by the natural movement of the air. They’re typically placed in more rural areas with higher wind speeds and fewer obstacles that may obstruct the flow of wind.
These turbines have large blades that rotate and drive a generator, and generally have a capacity between 2.5 to 3 MW. The blades are typically around 50 metres in length, but they can be slightly larger or smaller depending on the turbine manufacturer and a developer’s requirements for a site.
Height-wise, the average onshore wind turbine is around 98 metres, but this can vary based on the capacity of a site.
Offshore wind turbines
These wind turbines are much larger, and they take the force of winds out at sea and transform it into electricity. They’re often more efficient than onshore wind turbines and hardier, too, as they’re built to deal with far stronger winds.
The technology used in offshore and onshore turbines is largely similar, but wind speeds offshore are far more reliable. So they produce more energy, but are harder to maintain, as they’re tricky to access.
Unlike onshore turbines, offshore turbines require submarine cables to link the structures together along with jackets and modules that make up the marine electrical substation. Offshore turbines are generally taller than onshore turbines, with each one being approximately 190 metres tall.
If you want to learn more about the difference between onshore and offshore wind turbines, check out our dedicated blog post on the topic right here.
What About Domestic Turbines?
The turbines I’ve discussed so far are utility-scale turbines that you may find on a wind farm. But we must also consider residential (or domestic) turbines in this discussion.
You place domestic turbines on the roof of a house (due to limited space) and feed electricity directly to the home.
They’re typically less efficient than larger-scale turbines, as they’re smaller and you can’t place them too high on a property.
However, one advantage of roof-mounted turbines is that a 1kW system typically costs around £2,000 to set up. Compared to solar panels, which often cost upwards of £7,000, investing in wind can save you a significant amount.
The main disadvantage of installing turbines on your property is that you may need more power to run an entire home. So, you may also need to invest in solar panels or use traditional methods.
Which Type of Turbine is Best?
Horizontal-axis turbines work best when it comes to converting the kinetic energy of wind into electrical power with excellent efficiency.
Vertical axis turbines are often better for built-up, urban areas where there may be limited space.
In short, it entirely depends on the situation – so do your research before diving in.
Looking to install a turbine on your land? Contact our expert team. We’ll take you through the options for a commercial-level wind farm and offer advice on negotiating the best financial deal.
If you’re new to the renewable energy sector, we’ll guide you through the entire process. From initial option agreements to final leases and maintenance phases, we’ll lend a helping hand.
