Wind Energy Overview

The use of wind power has been around for thousands of years in different forms and nowadays is mainly used to generate electricity. Take a look at our wind energy facts page for some of the ways wind power was used in days gone by.

The proper name of a wind generator is actually “Wind Energy Converter” which is a device that converts the potential energy in the wind to another form of Wind Power energy. This can either be mechanical or electrical. When the wind blows, the rotor blade stops a percentage of the wind. That percentage is converted into energy. According to physics, the maximum amount of wind energy that can be converted is 59.3%. This is known as the Betz Limit.

There are a number of types of wind generators and research has been done on virtually every possible concept with the objective of producing the maximum amount of power for the lowest cost at the highest possible reliability. Experiments have found the horizontal axis upwind or down wind design to be the best concept. The most common designs include: 

• Horizontal Upwind - The generator shaft is positioned horizontally and the wind hits the blade before the tower.
• Horizontal Downwind - The generator shaft is positioned horizontally and the wind hits the tower first then the blade.
• Vertical Axis - The generator shaft is positioned vertically with the blades pointing up with the generator mounted on the ground or a short tower.
 

Wind power is proportional to the cube of the wind's speed, so relatively minor increases in speed result in large changes in potential output. Individual turbines vary in size and power output from a few hundred watts to two or three megawatts (as a guide, a typical domestic system would be 2.5 - 6 kilowatts, depending on the location and size of the home). Small domestic systems cost as little as £2,000 installed, although these small turbines may not contribute significantly to your energy needs. Visit some of the pages in the menu below for more information on domestic wind power.

 How it works:   

The Sun heats our atmosphere unevenly, so some patches become warmer than others.  

These warm patches of air rise, other air blows in to replace them - and we feel a wind blowing.

We can use the energy in the wind by building a tall tower, with a large propellor on the top. 

The wind blows the propellor round, which turns a generator to produce electricity.  

We tend to build many of these towers together, to make a "wind farm" and produce more electricity. 

The more towers, the more wind, and the larger the propellors, the more electricity we can make.  

It's only worth building wind farms in places that have strong, steady winds, although boats and caravans increasingly have small wind generators to help keep their batteries charged.

The best places for wind farms are in coastal areas, at the tops of rounded hills, open plains and gaps in mountains - places where the wind is strong and reliable. Some are offshore.

To be worthwhile, you need an average wind speed of around 25 km/h. Most wind farms in the UK are in Cornwall or Wales.

Isolated places such as farms may have their own wind generators. In California, several "wind farms" supply electricity to homes around Los Angeles. 

The propellors are large, to extract energy from the largest possible volume of air. The blades can be angled to "fine" or "coarse" pitch, to cope with varying wind speeds, and the generator and propellor can turn to face the wind wherever it comes from. Some designs use vertical turbines, which don't need to be turned to face the wind.  

The towers are tall, to get the propellors as high as possible, up to where the wind is stronger. This means that the land beneath can still be used for farming. 

Advantages:

• Wind energy is friendly to the surrounding environment, as no fossil fuels are burnt to generate electricity from wind energy.
  
• Wind turbines take up less space than the average power station. Windmills only have to occupy a few square meters for the base, this allows the land around the turbine to be used for many purposes, for example agriculture.
  
• Newer technologies are making the extraction of wind energy much more efficient. The wind is free, and we are able to cash in on this free source of energy.
  
• Wind turbines are a great resource to generate energy in remote locations, such as mountain communities and remote countryside. Wind turbines can be a range of different sizes in order to support varying population levels.
  
• Another advantage of wind energy is that when combined with solar electricity, this energy source is great for developed and developing countries to provide a steady, reliable supply of electricity.
  

 

Disadvantages:

• The main disadvantage regarding wind power is down to the winds unreliability factor. In many areas, the winds strength is too low to support a wind turbine or wind farm, and this is where the use of solar power or geothermal power could be great alternatives.
  
• Wind turbines generally produce allot less electricity than the average fossil fuelled power station, requiring multiple wind turbines to be built in order to make an impact.
  
• Wind turbine construction can be very expensive and costly to surrounding wildlife during the build process.
  
• The noise pollution from commercial wind turbines is sometimes similar to a small jet engine. This is fine if you live miles away, where you will hardly notice the noise, but what if you live within a few hundred meters of a turbine? This is a major disadvantage.
  
• Protests and/or petitions usually confront any proposed wind farm development. People feel the countryside should be left in tact for everyone to enjoy it's beauty.
  

 

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