The history of river energy:

Above - Water wheel used to generate electricity in Aberdulais, South Wales.

The power of moving water has long been recognised. Rivers have been used as transport corridors for thousands of years. The ancient Egyptians floated down the Nile River on the water current and they learned to harness the wind’s energy to sail up it again. Essentially, river-based water power is another form of indirect solar energy because it uses the potential energy in rain water (or melted snow) as it drains back to the oceans. The available energy depends on the quantity of water (the flow) and the drop in elevation along the path of flow (head). The energy in the stream of water is converted to rotational energy by means of a water wheel or turbine. One litre of water, falling about 150 metres per second, can generate one kilowatt of electricity.

Around 200 BC, the water wheel was the first invention created to harness the mechanical power of water. The water wheel was developed more than 2,000 years ago in two forms – horizontal and vertical. The vertical wheel was first used to lift water and drain mining pits; it was driven treadmill-fashion by people climbing around its circumference. Soon afterwards, people recognised that flowing water could turn the wheel. Then dams (mill ponds) and channels were built to control the flow of water. The horizontal wheel could drive its millstones directly and was simple to build and repair. The vertical wheel needed a pair of gear wheels to turn the rotating force through 90 degrees but it was much more powerful and efficient.

Water wheels were put to work in a wide variety of activities during the Middle Ages (which lasted until the fifteenth century). The power of water wheels was used to grind grain, operate the bellows of metal smelters and casters and to make paper and cloth. In 1090, a 12-metre high clock driven by waterwheels was built in northern China.

To view illustrations and photos of ancient water wheels, go to:
angelfire.com/journal/millbuilder/album5.html

Although it was from simple beginnings, the water wheel quickly progressed to substantial mill activities. We introduced ways to control the supply of water through mill ponds or dams. Mill ponds held a quantity of water and ensured there would always be a sufficient water flow to drive the mill’s grindstones. Also, as far back as the sixteenth century, early in the Industrial Revolution in Britain, factories used water wheels to turn machinery for the production of cloth. Early in the nineteenth century, the water wheel made way for the latest water turbine technology.

For more information about the history of water wheels, go to:
http://www.waterhistory.org/histories/waterwheels/

The world’s first hydro-electric power plant began operating on the Fox River in Appleton, Wisconsin USA on 30 September 1882. The plant, later named the Appleton Edison Light Company, was initiated by Appleton paper manufacturer H.F. Rogers, who had been inspired by Thomas Edison’s plans for an electricity-producing station in New York. Edison was responsible for the discovery of the generation of low-voltage direct current (DC) during the late nineteenth century. The Appleton hydro-electric plant used the energy of the Fox River. The operation's water wheel, generators, and copper wiring took only a few months to install and test. When the plant opened, it produced enough electricity to light Rogers' home, the plant itself, and a nearby building.

For more information about Thomas Edison’s hydro-electric power plant, go to:
http://www.americaslibrary.gov/cgi-bin/page.cgi/jb/gilded/hydro_1

George Westinghouse (who founded the General Electric Company) harnessed the great power of Niagara Falls. The General Electric Company was based on the high-voltage alternating current system developed by the Croatian engineer Nikola Tesla. In 1887, Tesla obtained American patents for his new motor that produced alternating current (AC). Tesla’s transformers stepped up and stepped down the high-voltage electricity as required. Westinghouse purchased the rights to use Tesla’s AC motor. In 1896, Westinghouse’s hydro-electric plant at Niagara transmitted massive amounts of power (40MW) to Buffalo, New York, more than 20 miles away.

With Niagara, Westinghouse convincingly demonstrated the superiority of transmitting power with electricity rather than by mechanical means, as well as the transmission superiority at that time of alternating current (AC) over direct current (DC). Niagara set a contemporary standard for generator size, and was the first large system supplying electricity from one circuit for multiple end-uses (railway, lighting, power).

For more information about Tesla’s discovery of alternating current, go to:
http://www.teslasociety.com/ac.htm

For more information about Westinghouse’s first power plant at Niagara Falls, go to:
http://www.pbs.org/tesla/ll/ll_niagara.html

Google Earth -Niagara Falls

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