Watermills are one of the newest, yet oldest, forms of producing clean energy. Though traditionally waterwheels have been used to generate mechanical power, instream energy technology, as it is called, is a relatively newer form of an old technology. This technology can tap the energy of flowing streams, rivers or canals. The kinetic energy of water in this case is converted into electricity.
Production of Electricity
The technology of producing electricity from watermills is known as Instream Energy Generation Technology (IEGT). To make electricity, turbines are placed in the moving waters where the current is strongest. The flow of the river is used to turn the turbines, and these turbines, in turn, generate electricity which is transported to the nearest grid on land. This is different from hydroelectricity because it uses the natural current of water, without building dams and reservoirs
Types of Turbines
There are several types of turbines that can be used to produce electricity. These turbines are chosen based on the water site. The most commonly used turbines are axial flow rotor turbines. These are comprised of radial blades, resembling a windmill. An open center fan turbine consists of two small donut-shaped turbines that rotate in a direction opposite to the water current. A helical turbine contains hydrofoil sections which allow the turbine to move in the direction of the current. Flutter vanes are turbines which look like huge Venetian blinds.
Advantages of Instream Energy Generation Technology
There are several advantages of Instream Energy Generation Technology. Since most population centers are close to rivers, this clean energy technology can reach out to areas with dense populations. This also makes building expensive dams unnecessary. This technology not only generates electricity but also runs irrigation systems.
Historical Use of Watermills
Watermills have historically been used for turning machinery, especially grinding stones. The Greeks invented watermills back in the 1st century BC. Watermills were created in the middle of rivers where the currents were strongest, and the kinetic energy of the water was used to move simple machinery that would grind corn and flour and make sails and needles.
Use of Electricity Generated by Watermills
Traditional watermills are still used in many rural areas in both underdeveloped and developing countries. The electricity generated by this technology can be transported to nearby settlements where the electricity grid has not yet reached. This technology can be combined with CFT (Compact Fluorescent Lamp) or LED (Light Emitting Diode) lighting. An existing watermill can be easily converted into an electricity generator. However, this cannot produce large amounts of electricity.