Learning Experience 1.3 WIND POWER Name: Date: Class: As the Sun shines on the Earth it warms the atmosphere more in some places than others. Warmer regions in the atmosphere are less dense than surrounding cooler areas so the warmer air rises upwards by the process of convection. Cooler air from surrounding areas rushes in to replace the rising warm air. This is what we feel as wind. Because wind is caused by the Sun, wind energy is actually a form of indirect solar power. How does wind power work? We use wind energy in many different ways, from sailing boats to flying kites. In terms of generating electricity, it works as follows: the kinetic energy of the wind is used to spin a propeller linked to a generator the generator consists of a system of magnets and coils of wire when the propeller spins, it makes the magnetic field from the magnets in the generator pass over the coils of wire, which causes an electrical current to flow. Efficiency A large turbine can have an efficiency of up to 40%.This means that for every 100 joules of kinetic energy in the wind striking the turbine blades, the turbine produces up to 40 joules of electrical energy. It is unlikely that a wind turbine will ever be much more efficient than this. If you think about what would happen to a 100% efficient wind turbine you can see why. If a turbine were 100% efficient it would transform 100% of the wind's energy into electrical energy. This means that the wind would have no energy left once it had passed through the turbine blades and would stop moving. This would effectively block more wind from passing through the blades and your turbine would grind to a halt! Eco credentials Wind power produces zero emissions. Wind turbines do not produce carbon dioxide and they make use of a totally renewable energy resource. Some people have concerns about possible noise pollution and harm that turbines may cause to local bird populations. Source: BP’s Carbon Footprint Calculator, Fact Sheet 11: Wind Power Use the information above to complete the activities on this worksheet. Describe in your own words how wind energy is in fact ‘indirect solar power’. ______________________________________________________________ ______________________________________________________________ ______________________________________________________________ ______________________________________________________________ ______________________________________________________________ ______________________________________________________________ ______________________________________________________________ ______________________________________________________________ ______________________________________________________________ ______________________________________________________________ ______________________________________________________________ Draw and label a wind turbine in the box below. How can wind power be used to create electricity? ______________________________________________________________ ______________________________________________________________ ______________________________________________________________ ______________________________________________________________ ______________________________________________________________ ______________________________________________________________ ______________________________________________________________ ______________________________________________________________ ______________________________________________________________ ______________________________________________________________ ______________________________________________________________ How efficient is a wind turbine? How come it is unlikely that a turbine will ever be created that is more efficient than this? ______________________________________________________________ ______________________________________________________________ ______________________________________________________________ ______________________________________________________________ ______________________________________________________________ ______________________________________________________________ ______________________________________________________________ ______________________________________________________________ ______________________________________________________________ ______________________________________________________________ ______________________________________________________________ What are the environmental impacts of wind energy, both positive and negative? ______________________________________________________________ ______________________________________________________________ ______________________________________________________________ ______________________________________________________________ ______________________________________________________________ ______________________________________________________________ ______________________________________________________________ ______________________________________________________________ Complete the energy transformation flow chart. Thermal energy from the _______ Why is the different density of hot and cold air so important to the formation and use of wind energy? ______________________________________________________ ______________________________________________________ ______________________________________________________ ______________________________________________________ ______________________________________________________ ______________________________________________________ ______________________________________________________ __________________________________________