On the Beat in Bluffton

Tuesday, November 8, 2011

A "wind"fall in Wells

County officials and the company Wind Capital Group took one step closer to bringing wind energy to Wells. To learn more about what officials still need to do, see the Tuesday, Nov. 8, News-Banner. To learn more about wind energy, read through the following, as taken by Wind Capital Group's website.

What is wind energy?
Wind energy is a converted form of solar energy. The sun’s radiation heats different parts of the earth at different rates - most notably during the day and night, but also when different surfaces (for example, water and land) absorb or reflect heat at different rates. This, in turn, causes portions of the atmosphere to warm differently. Hot air rises, reducing the atmospheric pressure at the earth’s surface, and cooler air is drawn in to replace it. The result is wind. Air has mass, and when it is in motion, it contains the energy of that motion (“kinetic energy”). Some portion of that energy can be converted into other forms of mechanical force or electricity that we can use to perform work.

What is a wind turbine and how does it work?

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.

Turbine subsystems include:
• a rotor, or blades, which converts 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
• electronic equipment such as controls, electrical cables, ground-support equipment, and interconnection equipment

* Some turbines do not require a gearbox.

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.

How big is a wind turbine?

Utility-scale wind turbines for land-based wind farms come in various sizes, with rotor diameters ranging from about 50 meters (164 feet) to about 120 meters (394 feet), and with towers of roughly the same size. A wind turbine that Wind Capital Group might use at this time has a total height from the tower base to the tip of the blade of approximately 400 feet.

What are wind turbines made of?
The towers are mostly tubular and made of steel. The blades are made of fiberglass reinforced polyester or wood-epoxy.

How much electricity can one wind turbine generate?
The output of a wind turbine depends on the turbine’s size and the wind’s speed through the rotor. Wind turbines being manufactured now have power ratings ranging from 250 watts to 5 megawatts (MW). Wind Capital Group typically uses 1.5 MW to 2.5 MW turbines. The ability to generate electricity is measured in watts. Watts are very small units, so the terms kilowatt (kW, 1,000 watts), megawatt (MW, 1 million watts) and gigawatt (pronounced “jig-a-watt,” GW, 1 billion watts) are most commonly used to describe the capacity of generating units like wind turbines or other power plants.Electricity production and consumption are most commonly measured in kilowatt-hours (kWh). A kilowatt-hour means one kilowatt (1,000 watts) of electricity produced or consumed for one hour. One 50-watt light bulb left on for 20 hours consumes one kilowatt-hour of electricity (50 watts x 20 hours = 1,000 watt-hours = 1 kilowatt-hour).

How big are wind farm projects?

Wind farms can range in size from a few megawatts to hundreds of megawatts in capacity, from one turbine to as large as 400 or more turbines. Wind Capital Group typically focuses on utility scale projects that are 50 MW or greater. Generally, this translates to 20 or more turbines, depending on the turbines used

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