What is Wind Energy?

Wind energy is a renewable energy source that is used to generate electricity by wind power. The term, wind power, means utilization of kinetic energy of wind to generate electricity. Wind energy is termed renewable source energy because it can never be exhausted. There are other renewable energy sources, such as solar energy, geothermal energy, hydropower energy, and so on. All of them contribute to power the thermal energy stations to generate electricity.

To generate wind power, the wind industry has to rely on wind farms that have multiple wind turbines installed in large open areas. The wind energy is converted into kinetic energy in the wind turbine blades, that is further transferred to the generator and is converted into electricity. This electricity is transferred to households by electricity grids. The size of a wind energy plant is recognized by its utility scale.

Selection of wind resources

Mere installation of wind turbines cannot result in the generation of electricity. Proper selection of geographical areas that have ample wind resources should be done after a thorough analysis. There are a lot of factors to be considered during wind farm selection. There are two types of wind farms, offshore wind farms, and onshore wind farms. Onshore windfarms rely on the wind generated from onshore water currents. On the other hand, offshore wind farms are land-based farms having the turbines installed away from water bodies. Based on the geographical area, there are four wind systems of earth, polar easterlies, tropical easterlies, the prevailing westerlies, and intertropical convergence zones.

A few factors to be considered in wind farm site selections are:

1. Wind speed: This is the most important factor while considering a geographical site. The energy of the wind must have enough power to turn the windmill blades. Wind power is directly related to wind velocity. A strong wind velocity will aid in large electrical energy generations, while a low wind speed will result in fewer electricity generations.
2. Wind frequency: The wind frequency denotes how often the wind flows. A steady place of the un-frequent flow of wind is a wrong choice of site selection. The wind energy recourse must have continuous wind flows that reduce the delay time of windmill blade rotation and standstill periods.
3. Good road access to sites: The windmills or wind turbines must be installed in properly selected places where there is proper road connectivity, this is helpful for installation and maintenance-related works.
4. Closer to electricity grids: The farm must be situated to a nearby electricity grid through which the electricity can be distributed to the lines.
5. Site altitude: Wind energy is related to wind flows, the frequency of flows is maximum at high altitude levels. The wind turbines must be installed at sites having high altitudes to generate adequate wind power.

Installation of wind turbines

Wind turbines are large energy conversion devices that convert wind energy into mechanical energy, which are ultimately converted to electrical energy. Wind turbines are tall structures having propeller-like rotating blades. The blades of wind turbines point toward the vertical axis. The wind always flows along the horizontal axis, so the direction of blades is such that they face the wind direction, which turns the blades of the wind turbine. The wind energy rotates the wind turbine blades, these wind turbine blades have generators that convert the mechanical energy from the blade rotation of the wind turbines into electrical energy.

Electricity grids

Electricity grids are the network of electrical lines which aids in the transfer of electricity from the productions plants to the consumer houses. The electrical energy generated inside the wind turbines is passed through suitable cables to the grids. The grid connected to the transmission lines directly transfers the electricity to households for consumption.

Capacity factor and energy consumption

The capacity factor denotes the maximum power output, when speaking power out, it signifies the power output of a wind energy generation plant. The capacity factor denotes the maximum wind power that can be obtained when the wind energy plant is operated for a specific period of time. The capacity factor also represents that how periodically the wind energy plant delivers maximum electrical power. A 100% capacity factor denotes the plant delivers power all the time and can account for the overall national power consumption.

The capacity of a wind power generator is usually measured in megawatt-hour or sometimes in smaller units such as kilowatt-hour.

The American Wind Energy Association based in Washington DC is a company dealing with various wind power projects that accounts for maximum wind power consumption over the US. The organization is also an equipment supplier dealer for wind power-related projects.

Context and Applications

The topic finds its application especially in the renewable resource industries dealing with wind turbines and their installation for electricity generations.

This topic is found in various engineering degree courses of bachelor of science specialized in mechanical engineering and production engineering. Besides, this topic is also studied as an interdisciplinary course of master of science.

• Bachelors in Technology in Mechanical Engineering
• Bachelors in Science (Wind Energy)
• Bachelors in Environmental Science
• Bachelors in Technology (Solar and Alternate Energy)

Practice Problems

1. Which is the first criteria that should be considered by wind farms for the installation of wind turbines?

1. Availability of wind turbine blades
2. Proper geographical location
3. Wind frequency
4. Both b and c

Correct option- d

Explanation: For the installation of wind turbines, a proper geographical location with adequate wind frequency must be considered.

2. Which of the following is a renewable energy source?

1. Solar energy
2. Wind energy
3. Nuclear energy
4. All of these

Correct option- d

Explanation: Solar energy, wind energy, nuclear energy, hydroelectric energy, geothermal energy, biogas and natural energies, and so on, are all examples of renewable energy sources.

3. Which of the following represents offshore wind farms?

1. Wind farms installed over water bodies
2. Land-based wind farms
3. Wind farms installed at higher altitudes
4. None of these

Correct option- b

Explanation: Wind farms that are installed over lands and free of water bodies are termed offshore wind farms.

4. Which of the following is true for a wind turbine?

1. Converts mechanical energy into electrical energy
2. Converts wind energy into electrical energy
3. Converts electrical energy into mechanical energy
4. Both a and b

Correct option- a

Explanation: Wind turbine is a device that converts the kinetic energy of wind into mechanical energy in the propeller blades. Due to the blade rotations, the mechanical energy is converted to electrical energy.

5. Which of the following is the unit of electricity generation by a power plant?

1. Megawatt-hour
2. Watt-hour
3. Megawatts
4. Kilowatts

Correct option- c

Explanation: The capacity of electricity generation of an electric power plant is measured in bigger units such as Megawatt-hour.