The Efficiency of Wind Energy: How to Calculate?

The Efficiency of Wind Energy: How to Calculate?

Please continue reading if you want to learn more about wind energy’s effectiveness. We can also tell you how to calculate it.

Utilizing wind to generate electricity is referred to as wind energy or wind power. The typical wind turbine efficiency ranges from 35 to 45%. A wind turbine extracts energy by reducing the speed of passing winds. A wind turbine would need to completely stop all wind after it makes contact with it in order to operate at 100% efficiency.

For readers who want to learn more about the effectiveness of wind turbines, this article includes information.

Wind Efficiency and Wind Capacity Factor

When discussing energy efficiency, people commonly confuse wind efficiency with wind capacity factor. The distinction between the two occurrences is made by Wind Watch.

Read More: Wind Energy Pros and Cons: An Ultimate Explanation

Wind Efficiency and Its Limit

The percentage of kinetic energy in the wind that is transformed into mechanical and electrical energy is known as wind efficiency. The highest theoretical limit is 59.6%, according to the physics laws described by the Betz Limit. The remaining energy is needed by the wind to push past the blades.

If a turbine captured all available energy, the wind would cease to blow and the turbine’s blades would be unable to turn, which is actually a good thing.

The Efficiency of Wind Energy: How to Calculate?

However, no machine is currently able to convert all of the 59.6% of trapped wind kinetic energy into electricity. The amount of energy that is ultimately converted to power is limited by the design and construction of generators.

As mentioned above, the current average ranges from 35 to 45%. The maximum at peak performance could reach 50% according to Wind Watch. The maximum achievable wind efficiency, according to an NSW government document from Australia, is 50%.

Energy efficiency is less variable than the wind capacity factor, which is greatly influenced by location and weather.

Wind Capacity Factor

The wind capacity factor is the amount of energy produced by a generator as against what it could produce if it functioned all the time at peak capacity, according to Green Tech Media.

According to Open EI, the wind capacity factor varies from location to location and throughout the year, even with the same turbines, because it depends on the wind’s speed, density, and swept area, which depends on the size of the generator.

By locating facilities in areas with ideal wind conditions for the majority of the year, it is possible to maximize the wind capacity factor. In order to maximize power output, it is crucial to take the wind capacity factor and the factors affecting it into account.

  • Wind speed below 30 miles per hour produces little energy according to Wind Watch. Even small increases in speed can translate into a substantial increase in power generated according to Open EI. Wind EIS states that electricity produced is equal to the square of wind speed.
  • Air density is more in cooler regions and at sea level than in mountains. Therefore, according to Open EI, areas with higher wind density are best located near colder seas. This is one of the factors driving off-shore wind generation’s significant growth.
The Efficiency of Wind Energy: How to Calculate?
  • Larger and taller turbines can take advantage of more wind higher above the ground and by the increased span of their blades. Economic considerations, therefore, become important here.

With advances in technology, the capacity factor is constantly rising. In comparison to wind turbines built between 2004 and 2011, which had a capacity factor of 31.2%, those built in 2014 had a 41.2% capacity factor.

However, the capacity factor of wind is affected not only by technology but also by wind availability itself. Thus, in 2015 capacity factor of turbines was below the previous year’s average due to “wind drought” explains Green Tech Media.

Wind Turbine Efficiency Formula

In order to compare the performance of various wind turbines and determine the ideal wind speed for maximum efficiency, efficiency calculations are crucial.

The term “wind turbine efficiency” is more frequently used to refer to co-efficient of power. The Cp is defined as,

The Efficiency of Wind Energy: How to Calculate?

A wind turbine’s output as a generator can be used to estimate how much electricity it produces. The below equation calculates the input kinetic energy,


The Efficiency of Wind Energy: How to Calculate?

A is the covered area of the wind turbine, V is the wind speed, and ρ is the air density.

The efficiency of the operating wind turbine varies as a result of the Cp value’s variation with respect to wind speed.

The Efficiency of Wind Energy: How to Calculate?

The Cp is additionally dependent on turbine components, i.e. the turbine blades, shafts, and generator. In order to calculate the value of Cp, the mechanical efficiency of the shaft, the electrical efficiency of the generator, and their sum total are multiplied.

You can learn more about other types of power plants, such as Nuclear Power Plants, Hydroelectric Power PlantsThermal Power PlantsGeothermal Power PlantsSolar Power PlantsTidal Power Plants, and Biomass Power Plants.

Comparison With Other Power Sources

The wind has a higher energy efficiency than coal. Gas has nearly the same efficiency as wind because it can convert 32–50% of its energy into electricity, whereas coal only converts 29–37% of its energy into electricity.

However, in terms of capacity factors, fossil fuels performed better than wind in the U.S. in 2016 according to the U.S. Energy Information Administration (EIA).

  • American coal plants ran at 52.7% of their capacity.
  • The capacity factor for gas plants was 56% in the US.
  • The EIA reported that the capacity factor for nuclear power was 92.5% for non-fossil fuels.
  • The capacity factor for hydropower was 38%.
  • Wind power’s capacity factor was 34.7%.

It is preferable to take into account both the energy efficiency and the capacity factor when comparing the power output from various energy sources. Due to the fact that fossil fuels also have pollution issues, increasing the power generation from wind is competitive and feasible.

Read More: Is Solar Or Wind Energy Better? Which to Choose?


Why is Wind Energy More Efficient?

Not only is wind an abundant and inexhaustible resource, but it also provides electricity without burning any fuel or polluting the air. Wind continues to be the largest source of renewable power in the United States, which helps reduce our reliance on fossil fuels.

Why Are Windmills Not 100% Efficient?

All of the wind’s energy would need to be converted into electricity for a wind turbine to be 100% effective. Or, to put it another way, the wind’s entire energy would be transformed, and the air would cease to move. This is not possible in practice because a rotor only spins if the wind passes over the blades.

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