HOW IS ENERGY GENERATED IN A HYDROELECTRIC POWER PLANT?

You may not realize it, but hydroelectric power is hardly a new invention. It is one of the oldest sources of energy and was used thousands of years ago to turn a paddle wheel for purposes such as grinding grain. Our nation's first industrial use of hydropower to generate electricity occurred in 1880, when 16 brush-arc lamps were powered using a water turbine at the Wolverine Chair Factory in Grand Rapids, Michigan.

The first U.S. hydroelectric power plant opened on the Fox River near Appleton, Wisconsin, on September 30, 1882. Until that time, coal was the only fuel used to produce electricity. Because the source of hydropower is water, hydroelectric power plants must be located on a water source. Therefore, it wasn't until the technology to transmit electricity over long distances was developed that hydropower became widely used.

It is also unique to note that of the renewable energy sources that generate electricity, hydropower is the most often used. It accounted for 7 percent of total U.S. electricity generation and 73 percent of generation from renewables in 2005.

So how does this 'old' concept actually work?

Mechanical energy is derived by directing, harnessing, or channeling moving water. The amount of available energy in moving water is determined by its flow or fall. Swiftly flowing water in a big river, like the Columbia River along the border between Oregon and Washington, carries a great deal of energy in its flow. So, too,with water descending rapidly from a very high point, like Niagara Falls in New York.

A hydroelectric power plant consists of a high dam that is built across a large river to create a reservoir, and a station where the process of energy conversion to electricity takes place. The first step in the generation of energy in a hydropower plant is the collection of run-off of seasonal rain and snow in lakes, streams and rivers, during the hydrological cycle. The run-off flows to dams downstream.

The water falls through a dam, into the hydropower plant and turns a large wheel called a turbine. The turbine converts the energy of falling water into mechanical energy to drive the generator. It turns a shaft, which rotates a number of magnets in the generator. When the magnets pass copper coils a magnetic field is created, which aids the production of electricity.

So once the power is created, how does it get to those who need it? Step-up transformers will then increase the voltage of the electricity, to levels needed for the journey to communities. After this process has taken place electricity is transferred to the communities through transmission lines and the water is released back into the lakes, streams or rivers. This water use is not harmful, because no pollutants are added to the water while it flows through the hydropower plant.

Even though the concept maybe old, modern engineering in combination with natural movements of water can safely produce a clean source of power at a cost-effective price. In the day where energy costs continually rise, we should appreciate hydroelectric power for their contributions.