Wind energy

Wind energy is another kind of renewable energy as it is clean and operates without emitting greenhouse gases. Basically, wind power is the conversion of kinetic energy of wind into useful form of energy through turbines (Figure 1). Normally, it is used for producing electricity. According to the calculation made by Hurley (2009), the world 's wind resources are estimated to be 50000 TWh/year. In fact, the total world primary energy consumption in 2008 is about 21283 TWh (IEA, 2010). The total available global wind resource on land is therefore more than adequate to supply a very significant proportion of the overall world's energy demand.

Figure 1. Structure of wind turbine

As most renewable energy sources without emission of pollutants such as SOx and NOx they will form the basis of any long-term sustainable energy supply system.  By 2020, taking EWEA projections that 180GW of wind energy would be generating 425 TWh per annum, wind power will save about 215 million tonnes CO2, 261,000 tonnes SO2 and 333,000 tonnes NOx comparing with the supply system depends on fossil fuels.

However, the disadvantages of using wind energy is obvious. Firstly, it cause visual impact on the surrounding. For example, the wind turbine would lead to light flash when the Sun is low in the sky east or west of the turbines. Secondly, the large wind turbines that used by power plants would threat the life of bird. A study in 2001 in the United States have estimated that each wind turbine has an average fatalities of 2.2 for birds. Finally, wind turbine would also create aerodynamic noise during the operation. Basically, the noise level increase with the speed of rotation in the turbines. So modern turbines operates with low speed to alleviate it.

Reference

Hurley Brain (2009). How Much Wind Energy is there? Wind Site Evaluation Ltd.

IEA Key energy statistics 2010 (2010).

WWEA (2011). World Wind Energy Report 2010.WWEA Head Office Charles-de-Gaulle-Str. 5 53113 Bonn Germany

EWEA (2010). WIND ENERGY AND THE ENVIRONMENT. Renewable Energy House 26, rue du Trône  B-1000 Brussels  Belgium