There are two types of wind machines used today: horizontal–axis wind machines and vertical-axis wind machines. Most windmills are the horizontal-axis type. One wind machine can produce 1.5 to 4.0 million kilowatthours (kWh) of electricity a year. That is enough electricity for to power 150-400 homes.

1) Horizontal-axis

Horizontal-axis wind machines have blades like airplane propellers. A typical horizontal wind machine stands as tall as a 20-story building and has three blades that span 200 feet across. The largest wind machines in the world have blades longer than a football field! Wind machines stand tall and wide to capture more wind.

2) Vertical-axis

Vertical–axis wind machines have blades that go from top to bottom and look like giant egg beaters. The typical vertical wind machine stands 100 feet tall and 50 feet wide. Vertical-axis wind machines make up just five percent of the wind machines used today.

The Wind Amplified Rotor Platform (WARP) is a different kind of wind system that is designed to be more efficient and use less land than wind machines in use today. The WARP does not use large blades; instead, it looks like a stack of wheel rims. Each module has a pair of small, high capacity turbines mounted to both of its concave wind amplifier module channel surfaces. The concave surfaces channel wind toward the turbines, amplifying wind speeds by 50 percent or more. Eneco, the company that designed WARP, plans to market the technology to power offshore oil platforms and wireless telecommunications systems.

The costs of wind energy 

The cost of wind energy is determined by:

• the initial cost of the wind turbine installation 

• the interest rate on the money invested 

• the amount of energy produced 

Any wind turbine that is installed in a very windy area generates less expensive electricity than the same unit installed in a less windy area. So it’s important to assess the wind at the potential site.

Modern wind turbine generators cost between $1500 and $2000 per kilowatt for wind farms that use multiple-unit arrays of large machines. Smaller individual units cost up to $3000 per kilowatt. In good wind areas, the costs of generating electricity range between five and ten cents per kilowatt hour. That cost is somewhat higher than the costs associated with an electrical facility, but wind energy costs are decreasing every year, whereas most conventional generation costs continue to increase. 

In remote areas, generating electricity with diesel generators can range from $0.25 to $1.00 per kilowatt hour. So in good wind areas, electricity that is generated by the wind is clearly cost effective. When compared to the money that is charged by electrical companies, wind energy costs are nearly competitive. And that is without accounting for the environmental and health benefits of using a non-polluting source of energy.

Using wind energy around the world

The use of wind turbine generators is growing around the world. In terms of installation and operation worldwide, the wind power industry now turns over more than 9 billion USD. At the end of 2004, 47,000 megawatts of wind-generated electricity produced some 92 TWh of electricity. That is sufficient energy for the electricity needs of Portugal and Greece combined.

The benefits of wind energy

Wind energy is an ideal renewable energy because:

• it is a pollution-free, infinitely sustainable form of energy    

• it doesn’t require fuel   

• it doesn’t create greenhouse gasses   

• it doesn’t produce toxic or radioactive waste.

Wind energy is quiet and does not present any significant hazard to birds or other wildlife.    

When large arrays of wind turbines are installed on farmland, only about 2% of the land area is required for the wind turbines. The rest is available for farming, livestock, and other uses.