Frequently Asked Questions on Wind Power （在风力发电常见问题）.pdfVIP

Frequently Asked Questions on Wind Power Programme (FAQ) 1. What is wind? Wind is air in motion. Wind is mainly formed due to the Earth’s rotation and the uneven heating of Earth’s surface by sunrays. The sunrays cover a much greater area at the equator than at the poles. The hot air rises from the equator and expands toward the poles that cause wind. Air has a mass and mass in motion has a momentum. Momentum is a form of energy that can be harvested. Pwind = × × × Where, 2 Pwind = Power in the wind (W/m ) 3 ρ = Air density (kg/m ) 2 A = Projected area (m ) (wind turbine rotor area) V = average wind speed (m/s) the power increases with cube of wind speed 2. What is a wind turbine? A wind turbine is a system which transforms the kinetic energy available in the wind into mechanical or electrical energy that can be harnessed for any required applications. Mechanical energy is most commonly used for pumping water. Wind electric turbines generate electricity that can be utilized locally or transported to the desired location through grid. 3. What are the different configurations of Wind Turbines? There are two basic configurations of Wind Turbines. One is Vertical axis wind turbine and the other is Horizontal axis wind turbine. The horizontal axis turbine has seen technological and economical growth and it has become the commonly used commercial turbines on large scale and the vertical axis turbines are still in the demonstration purpose a