Wind energy is an important segment of the main six renewable energy sources (biomass, hydropower, ocean energy, geothermal, wind, and solar).

Renewables account for 9% of electricity generation in the United States. Historically,  the wind has been used for thousands of years as a source of energy, for example to power entire fleets of merchant ships and war vessels, but also for windmills which were used for pumping water to drain fields.

Today, wind energy accounts for approximately 6% of renewable energy generation. Its operating and construction costs have come down lately, making this alternative source of energy competitive with traditional sources of energy. The top three wind generating countries are Germany, Spain, and the United States. In Germany, large parts of the North shore have an abundance of strong winds and are therefore ideally suited for power plants. In the United States, wind parks can often be found in elevated desert areas such as the area between Los Angeles and Palm Springs, where one of the largest parks of the world is located.

How does wind energy work? To cut a long story short, wind rotates a turbine which transforms mechanical energy (kinetic energy) into electricity. The power produced is proportional to the third power of the wind velocity.

Advantages:

  1. Free energy source.
  2. No greenhouse gas emissions.

Disadvantages:

  1. This form of renewable energy is not useful as a baseload power source. A turbine cannot produce energy if the wind speed is too low or too high.
  2. The amount of output varies with speed.
  3. Suitable sites for wind turbines are often far away from areas that need electricity.
  4. Turbines have very high visibility. 
  5. Noise emission.

Let me explain why exactly this for of energy is so inefficient. In theory, total power could be captured only if the wind velocity is reduced to zero when it passes through the blades of the turbine. In a realistic turbine this is impossible, as the captured air must also exit the turbine and cannot be "caught within". Mathematically, the maximal achievable extraction by a wind turbine is 59% of the total theoretical power. The optimal speed must also be greater than 14 mph and less than 50 mph for traditional turbines (higher for newer designs), otherwise, no energy can be produced.