Wind Power Systems, Using Wind as an Electrical and Mechanical Power Source

Background
What Are Wind Energy Systems?
Mechanical Energy Systems
Windmills
Wind Driven Water Pumps
Sailing Ships
Wind Powered Electrical Energy Systems
How Do Wind Turbines Work

Background

The wind has been used as an energy source for thousands of years. Even the earliest and most primitive people used wind energy as means of transportation by rigging sails to various rafts, boats and watercraft.

What Are Wind Energy Systems?

There are two basic types of system that are used to capture wind energy. Both capture the kinetic energy of the wind and use it to either produce electrical energy or to power a mechanical system.

Mechanical Energy Systems

The oldest forms of harnessing wind energy are mechanical energy systems. Typical examples of this are sailing ships, wind driven water pumps, windmills used for crushing grain and windmills used for directly powering other industrial equipment.

Windmills

Practically applied industrial windmills have been reliably documented are known to have been used since the 9th Century.

Figure 1. Traditional windmill used for crushing grain to make flour

Windmills remained a popular source of energy throughout Europe and the United States until the 1930s when reliable electricity supplies became widespread. By the 1950s windmills were rarely used but increases in energy costs mean new, efficient windmills are attracting a surge in interested from suitable industries.

Wind Driven Water Pumps

Wind driven water pumps are used to pump water from wells, dams, rivers and for draining flooded land. They have faced being replaced by electric pumps, diesel pumps and solar pumps but their simple and reliable construction means wind driven water pumps are still widely used for pumping water in rural and remote parts of the world.

Figure 2. Typical windmill used for pumping water in remote and rural areas of Australia and the U.S.

Sailing Ships

Harnessing the wind using sails was first done by the Egyptians around 4000BC and has been gradually adopted around the world since then. Modern use of sails brings to mind either old square rigged tourist ships, recreational sailing or long distance ocean racing but sails are being rediscovered for industrial purposes. Massive kite-like sails are now available for use by modern container ships and bulk carriers. These sails are used in conjunction with normal propulsion systems but the sails reduce the burden on the ship's engines, saving fuel.

Figure 3. Traditional sailing ship

Wind Powered Electrical Energy Systems

The most widespread use of wind energy in the world today is in the production of electricity. The modern wind electricity industry began in Denmark in 1979 with manufacturers developing various wind turbines. These early turbines were quite small when compared to modern wind turbines. Wind power is a fast growing sector of the energy market with wind sourced power being safe, clean and renewable.

Figure 4. Modern wind turbines for producing wind electricity

How Do Wind Turbines Work?

Most wind turbines used today are horizontal-axis wind turbines where wind blows through propellor like blades, that turn a shaft, gearbox and a generator that produces electricity. The shaft, gearbox and generator are covered by an aerodynamically designed nacelle that is attached to a vertical pole that may be in excess of 100m tall. The turbine is carefully monitored and controlled to ensure maximum efficiency and to protect the turbine from damage in excessively high winds.

Modern wind turbines produce power from around 250 watts (for battery charging) to 1.8 megawatts or more. A large wind turbine of this size could provide enough power for around 5000 homes.

Source: AZoCleantech