The National Resources Defense Council (NRDC), on the "Issues: Oil & Energy" section of its website www.nrdc.org (accessed Oct. 14, 2008), wrote:
"The wind's kinetic energy can be harnessed by a wind turbine, a device that looks like an extremely tall, skinny fan. When wind moves the blades of the fan, they spin a central hub. The spinning hub moves a series of gears connected to a generator, which converts the mechanical energy into electrical energy for distribution."
The Office of Energy Efficiency and Renewable Energy (EERE) within the US Department of Energy (DOE), in a section on its website www.eere.energy.gov titled "How Wind Turbines Work" (accessed Oct. 15, 2008), wrote:
"...The terms wind energy or wind power describe the process by which the wind is used to generate mechanical power or electricity. Wind turbines convert the kinetic energy in the wind into mechanical power. This mechanical power can be used for specific tasks (such as grinding grain or pumping water) or a generator can convert this mechanical power into electricity.
So how do wind turbines make electricity? Simply stated, a wind turbine works the opposite of a fan. Instead of using electricity to make wind, like a fan, wind turbines use wind to make electricity. The wind turns the blades, which spin a shaft, which connects to a generator and makes electricity...
The electricity is sent through transmission and distribution lines to homes, businesses, schools, and so on..."
The American Wind Energy Association (AWEA), in a section of its website www.awea.org titled "Wind Energy Basics" (accessed Oct. 15, 2008), wrote:
"A wind energy system transforms the kinetic energy of the wind into mechanical or electrical energy that can be harnessed for practical use... Wind electric turbines generate electricity for homes and businesses and for sale to utilities.
There are two basic designs of wind electric turbines: vertical-axis, or "egg-beater" style, and horizontal-axis (propeller-style) machines. Horizontal-axis wind turbines are most common today, constituting nearly all of the "utility-scale" (100 kilowatts, kW, capacity and larger) 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 and drive train; and
electronic equipment such as controls, electrical cables, ground support equipment, and interconnection equipment...
...The electricity generated by a utility-scale wind turbine is normally collected and fed into utility power lines, where it is mixed with electricity from other power plants and delivered to utility customers. Today (August 2005), turbines with capacities as large as 5,000 kW (5 MW) are being tested."
Julia Layton, MFA, Contributing Writer at HowStuffWorks.com, an online resource for scientific information, in an article titled "How Wind Power Works" (accessed Oct. 15, 2008), wrote:
"...[A]ir moves quickly, in the form of wind, those particles are moving quickly. Motion means kinetic energy, which can be captured, just like the energy in moving water can be captured by the turbine in a hydroelectric dam. In the case of a wind-electric turbine, the turbine blades are designed to capture the kinetic energy in wind. The rest is nearly identical to a hydroelectric setup: When the turbine blades capture wind energy and start moving, they spin a shaft that leads from the hub of the rotor to a generator. The generator turns that rotational energy into electricity. At its essence, generating electricity from the wind is all about transferring energy from one medium to another.
Wind power all starts with the sun. When the sun heats up a certain area of land, the air around that land mass absorbs some of that heat. At a certain temperature, that hotter air begins to rise very quickly because a given volume of hot air is lighter than an equal volume of cooler air. Faster-moving (hotter) air particles exert more pressure than slower-moving particles, so it takes fewer of them to maintain the normal air pressure at a given elevation. When that lighter hot air suddenly rises, cooler air flows quickly in to fill the gap the hot air leaves behind. That air rushing in to fill the gap is wind.
If you place an object like a rotor blade in the path of that wind, the wind will push on it, transferring some of its own energy of motion to the blade. This is how a wind turbine captures energy from the wind."