A guide to wind energy What is wind power ? Wind turbine design Utility scale versus small wind Small wind power: cost-effective renewable energy Small wind power growth Grid-Connected and Off-Grid Applications Wind energy versus other renewable energy technologies. Click here for more information about solar from the Energy Smart website – http://www.energysmart.com.au/
What is wind power ?
Wind power is the generation of electricity from wind energy as a natural resource. Wind energy is a converted form of solar energy. This is how: The sun’s radiation heats different parts of the earth at various rates, with the greatest variations occurring between day and night. Since different earth surfaces such as water and land absorb and reflect heat at different rates, portions of the atmosphere vary in temperature. When hot air rises, it reduces the atmospheric pressure at the earth’s surface, and cooler air is drawn in to replace it. This drawing in of cooler air is what we experience as wind.
Air has mass. When this mass is in motion, it contains the energy of that motion known as kinetic energy. A wind energy system transforms the kinetic energy of the wind into mechanical or electrical energy that can be harnessed for practical use.
Popular uses for mechanical energy include pumping water – often seen in rural or remote areas – and commonly known as the farm windmill. In addition, mechanical energy is also used for many other purposes such as grinding grain, sawing, pushing a sailboat, etc.
Wind power consumes no fuel for its operation, and works without the emissions associated with electricity production. Wind power does not produce carbon dioxide, sulfur dioxide, mercury, particles, or any other type of air pollution that is caused by fossil fuel power sources.
Wind turbine design
There are two basic designs of wind electric turbines: Vertical-axis wind turbines (VAWT) and Horizontal-axis wind turbines (HAWT) “propeller” style machines. Horizontal-axis wind turbines are the most common today, constituting nearly all of the “utility-scale” (>100 kilowatts capacity) turbines in the global market.
Turbine subsystems include:
A rotor or blades, which convert the wind’s energy into rotational shaft energy
A nacelle (enclosure) containing a drive train, usually including a gearbox* and a generator
A tower to support the rotor
Electronic equipment such as controls, electrical cables, ground support equipment, and interconnection equipment
*Some turbines, including TechnoSpin turbines, do not require a gearbox
Growing wind power capacity
Over the past ten years, global wind power capacity has continued to grow at an average cumulative rate of over 30%. 2008 was a record year with more than 27GW capacity (a 36% increase over 2007), which was dominated by three main markets: Europe, North America and Asia.