Hydropower Working

Hydropower Plant

Worldwide, hydropower plants produce about 24 percent of the world's electricity and supply more than 1 billion people with power.

The world's hydropower plants output a combined total of 675,000 megawatts, the energy equivalent of 3.6 billion barrels of oil, according to the National Renewable Energy Laboratory. There are more than 2,000 hydropower plants operating in the United States, making hydropower the country's largest renewable energy source.

Moving water, such as a river or a waterfall, has mechanical energy. ‘Mechanical energy is the energy that is possessed by an object due to its motion or stored energy of position.’ This means that an object has mechanical energy if it’s in motion or has the potential to do work (the movement of matter from one location to another,) based on its position.

Hydropower Work

The energy of motion is called kinetic energy and the stored energy of position is called potential energy. Water has both the ability and the potential to do work. Therefore, water contains mechanical energy (the ability to do work), kinetic energy (in moving water, the energy based on movement), and potential energy (the potential to do work.)

The dam is usually built on a large river that has a drop in elevation, so as to use the forces of gravity to aid in the process of creating electricity. A dam is built to trap water, usually in a valley where there is an existing lake. An artificial storage reservoir is formed by constructing a dam across a river.Notice that the dam is much thicker at the bottom than at the top, because the pressure of the water increases with depth.

When the gate is opened, the water from the reservoir goes through the intake and becomes translational kinetic energy as it falls through the next main part of the system: the penstock. Translational kinetic energy is the energy due to motion from one location to another. The water is falling (moving) from the reservoir towards the turbines through the penstock. Gravity will force the water to fall to a lower position through the intake and the control gate. They are built on the inside of the dam.

The work that is done by the water to turn the turbines is mechanical energy. This energy powers the generators, which are very important parts of the hydroelectric power plant; they convert the energy of water into electricity. Most plants contain several generators to maximize electricity production. The penstock is a long shaft that carries the water towards the turbines where the kinetic energy becomes mechanical energy. The force of the water is used to turn the turbines that turn the generator shaft. The turning of this shaft is known as rotational kinetic energy because the energy of the moving water is used to rotate the generator shaft.