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• Demonstrate the force of water
  
• Make a Turbine
  
• Using Water to Produce Energy
  
• Generate Your Own Hydropower
  
• My Perpetual Motion Experiment
  
• Make Your Own Hydropower: Classroom Curriculum
  
• Guide to Hydro Power
  
• Build a hydro power plant
  
• Hydropower Lesson Plan (Grades 5-8)
  
• Water Renewable Energy Science Fair Projects and Experiments
  

Undershot water wheels on the Orontes River in Hama, Syria

Hydropower or hydraulic power is the force or energy of moving water. It may be captured for some useful purpose.

Prior to the widespread availability of commercial electric power, hydropower was used for irrigation, and operation of various machines, such as watermills, textile machines, and sawmills. A trompe produces compressed air from falling water, which could then be used to power other machinery at a distance from the water.

History

Hydropower has been used for hundreds of years. In India, water wheels and watermills were built; in Imperial Rome, water powered mills produced flour from grain, and were also used for sawing timber and stone. The power of a wave of water released from a tank was used for extraction of metal ores in a method known as hushing. Hushing was widely used in Britain in the Medieval and later periods to extract lead and tin ores. It later evolved into hydraulic mining when used during the California gold rush.

Gold miners excavate an eroded bluff with jets of water at a placer mine in Dutch Flat, California sometime between 1857 and 1870.

In China and the rest of the Far East, hydraulically operated "pot wheel" pumps raised water into irrigation canals. In the 1830s, at the peak of the canal-building era, hydropower was used to transport barge traffic up and down steep hills using inclined plane railroads. Direct mechanical power transmission required that industries using hydropower had to locate near the waterfall. For example, during the last half of the 19th century, many grist mills were built at Saint Anthony Falls, utilizing the 50 foot (15 metre) drop in the Mississippi River. The mills contributed to the growth of Minneapolis. Hydraulic power networks also existed, using pipes carrying pressurized liquid to transmit mechanical power from a power source, such as a pump, to end users.

Today the largest use of hydropower is for the creation of hydroelectricity, which allows low cost energy to be used at long distances from the water source.

Water power

Energy in water (in the form of motive energy or temperature differences) can be harnessed and used. Since water is about 800 times denser than air,^[1][2] even a slow flowing stream of water, or moderate sea swell, can yield considerable amounts of energy.

There are many forms of water energy:

• Hydroelectric energy is a term usually reserved for large-scale hydroelectric dams. Examples are the Grand Coulee Dam in Washington State and the Akosombo Dam in Ghana.
• Micro hydro systems are hydroelectric power installations that typically produce up to 100 kW of power. They are often used in water rich areas as a Remote Area Power Supply (RAPS). There are many of these installations around the world, including several delivering around 50 kW in the Solomon Islands.
• Damless hydro systems derive kinetic energy from rivers and oceans without using a dam.
• Wave power uses the energy in waves. The waves will usually make large pontoons go up and down in the water, leaving an area with reduced wave height in the "shadow". Wave power has now reached commercialization.
• Tidal power captures energy from the tides in a vertical direction. Tides come in, raise water levels in a basin, and tides roll out. Around low tide, the water in the basin is discharged through a turbine.
• Ocean thermal energy conversion (OTEC) uses the temperature difference between the warmer surface of the ocean and the colder lower recesses. To this end, it employs a cyclic heat engine. OTEC has not been field-tested on a large scale.
• Vortex power, which creates vortices which can then be tapped for energy
• Deep lake water cooling, although not technically an energy generation method, can save a lot of energy in summer. It uses submerged pipes as a heat sink for climate control systems. Lake-bottom water is a year-round local constant of about 4 °C.
• Blue energy is the reverse of desalination. This form of energy is in research.

References