How efficient are wind turbines? It is an important question, which in so many ways, helps determine the future of wind energy.
A wind turbine, often known as a windmill, is a mechanism that harnesses the kinetic energy of wind to power mechanical devices.
A wind generator then uses kinetic energy to create an electrical current. But, the question is, “how efficient are wind turbines for producing electricity?“
The efficiency of wind turbines depends on weather conditions and other factors.
But it is usually 30-45% and goes up a little in peak wind hours.
The Amazing Potential of Wind Power and Turbines
Harnessing wind energy is the way forward, especially because of its emissions benefits.
But, it can have an impact on other sectors, making people question, “how are wind turbines efficient?”
The biggest effect is in the job sector, as jobs made possible by wind energy tend to pay well.
Now, in all 50 states, the wind energy sector employs over 120,000 people, which is only expected to grow.
Data suggests that jobs servicing wind turbines are the second fastest expanding sector in the country during the past decade.
By 2050, the wind industry might provide hundreds of thousands of additional jobs, including those in manufacturing and management.
And to make all that happen, there have to be better, more efficient wind turbines.
More about Wind Turbines
Just think of a wind turbine as the exact opposite of your regular fan.
They reverse the usual process, turning the wind into power instead of the other way around.
The blades turn when the wind blows (it does not even have to be very powerful).
And the energy is converted from motion into electricity when a rotor is turned by the force of the motion.
Fact: Modern wind turbines are fascinating and can stand up to 150m tall.
The Basic Working of Wind Turbines
Wind turbines generate electricity simply by being exposed to wind.
Wind drives blades on a turbine, which in turn spins a rotor and a generator, generating power.
If you have ever tried to sail a boat or fly a kite, you will know that the wind has a lot of potential energy.
And windmills have been harnessing that potential energy for hundreds of years.
Now we know there is no shortage of wind power, but what additional considerations must be made when turning wind turbines into a reliable source of electricity?
And the two most important considerations are:
- Picking the Right Spot for Turbines
- Keeping the Turbines Facing the Wind
Picking the Right Spot for Turbines
Wind turbines are not always reliable, as is the case with many forms of natural energy.
Lack of wind, excessive wind speed, or gusty winds are all bad for wind turbines.
It is, therefore, essential to locate an area where the wind speed can be predicted with reasonable accuracy.
Hills, forests, valleys, and manmade structures all play a role in shaping the wind.
Wind turbines perform best on flat, high, and uninterrupted terrain because these factors deflect and modify the available power.
That is why you will find so many wind farms out at sea, and why some are perched precariously above hills.
Keeping the Turbines Facing the Wind
Wind turbines have to be facing toward the wind to generate power, so manufacturers include a unique sensor to ensure that this is the case.
The sensor should be sufficient to detect the strongest wind and cause the blades to react appropriately.
The direction of those blades can be altered using a complex framework hidden from view.
An interesting feature of these turbines is a built-in brake that engages when wind speeds become excessive.
An inefficient sensor directly impacts a wind turbine’s productivity, and this can hamper the outcomes considerably.
Fact: A wind turbine's efficiency also depends on its blade, which can be as long as 90m.
How Efficient are Wind Turbines?
Now to ensure that wind turbines make a difference and help convert wind into electricity, their efficiency matters.
An average wind turbine has an efficiency of 30-45%, reaching as high as 50% during times of high wind.
A wind turbine that was 100% efficient would cause the wind speed to drop to zero after passing through it.
That said, regional variations are possible. In the United Kingdom, for instance, wind turbines provide efficiency up to 70–80 percent, making them consistent power supply machines throughout the year.
How Efficient Can Wind Turbines Possibly Be?
If a wind turbine were perfect, it would turn every bit of the wind’s energy into power.
In other words, the wind would stop blowing since all of its energy would be used up in the transformation.
Since a rotor only turns when air flows over its blades, this is obviously impossible in real life.
If a rotor were to completely halt the flow of air, the turbine would be unable to harness the wind’s kinetic energy and turn it into electricity.
The Idea of Designing a Highly Efficient Wind Turbine
Albert Betz, a German physicist, determined that no wind turbine could be built to harness more than 59.3 percent of the wind’s kinetic energy.
And that is not possible to convert it into mechanical energy simply by spinning a rotor.
This theoretical upper bound on practical wind turbine efficiency is referred to as the Betz Limit, and it now stands at 59.3 percent (open airflow).
Most contemporary wind turbines have an efficiency between 25 and 45 percent in average operating winds.
The Technical Side to the Efficiency of Wind Turbines
When speaking about the efficiency of wind turbines, the Betz Limit is technically relevant only when it is about using the kinetic energy of the wind.
Furthermore, the overall efficiency is diminished by the wind turbine’s generator, which converts the available mechanical energy into electricity.
To get it more clearly, take the example of how wind turbine blades work.
The blades only use 50% of the available wind power and change it into mechanical energy.
After that, the generator kicks in and uses 80 percent of that energy and converts it into electricity.
As a result, the overall efficiency of this wind turbine would be 40%.
The Impact of Weather on the Efficiency of Wind Turbines
Researchers, engineers, and innovators in the wind energy industry are always thinking about ways to make wind turbines more effective.
It is the only way to ensure the long-term viability of the renewable energy sector and achieve significant worldwide penetration.
But, unfortunately, bad weather can have a significant impact on turbine siting and overall efficiency.
In the same way that cloudy days pose a problem for solar power, huge storms that lash coasts can make it difficult to generate electricity using wind turbines.
However, other natural factors can have similar effects.
- Salt corrosion
Offshore wind farms are located directly in the path of some of the world’s most violent storms. They form over the oceans and then travel onshore to coastal areas.
However, powerful gusts of wind can wreak havoc on wind turbines.
In fact, inland storms can disrupt the grid as well if there are not enough dependable power generators.
Constructing anything along the coast has always been fraught with difficulties due to corrosion from salt water. A wind turbine is not an exception.
Unfortunately, most materials degrade more quickly after being exposed to saltwater spray.
And the thing is that foundations for many offshore turbines are placed underwater, thus they must be constructed from extremely durable marine-grade materials.
Going with near-shore turbines makes salt corrosion less of an issue, but it is still there.
Humid, salty air causes wind turbines to corrode and oxidize at rates far higher than those observed in the Great Plains.
Fact: When weather is poor, and wind turbines are close to the sea, much more seawater is tossed about, increasing the rate of corrosion.
No matter the weather conditions, moisture in the air can always pose a challenge for wind turbines to work efficiently
Overtime, exposure to water can damage different components of wind turbines.
Although these turbines are not as expensive as offshore platforms used in the oil and gas industry, they can still make it difficult to manage costs.
Fact: Besides natural factors damaging wind turbines, it is hard to find trained professionals to fix those issues, further limiting their efficiency.
How efficient are wind turbines? In most cases, wind turbines are only 30-45% efficient.
But, the percentage goes up a little based on the weather conditions and wind speed.
Still, they just cannot be 100% efficient because they utilize potential energy from wind, and it is not possible to extract all that energy.