Hydroelectric Energy

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Hydroelectric Energy

Hydroelectric energy:

“Hydro” means “water” in Greek so as the name indicates the electric energy that is generated or produced using the energy or force in the water is called hydroelectric energy. Water has a gravitational force when it is falling of flowing so that energy is used to generate electricity.

The most widely used form of energy is this hydroelectricity. It is a form of renewable energy, whose cost of production is low when compared to other energy forms. This is also a flexible form because ramping up and down can be done very fast to meet out the demands.

The use of water energy dates back to the ancient times as they have used this to grind flour and have performed many other tasks.

Hydroelectric Energy : History

Bernard Forest de Bélidor in the middle of 1770 published Architecture Hydraulique. In the 19th century Electrical generator was established. In 1878, at cragside in Northumberland, England the first Hydroelectric power scehe was developed by William George Amstrong. That was used to light a lamp in his art gallery.

1881 – The old schoelkopf power station No.1

1882 – Edison Hydroelectric plant, the Vulcan Street plant

1886 – Appleton, Wisconsin

Basics of Hydroelectric energy generation:

Normally the hydro electric plants requires 3 major components

  • Construction of a hydro electric plant

  • A Dam to Channel the water flow

  • A reservoir to store the water.

The whole principle of hydroelectric power generation is based on Faraday’s law of electromagnetic induction

Faraday’s law of electromagnetic induction

It states that

Any change in the magnetic environment of a coil of wire will cause a voltage (emf) to be “induced” in the coil. No matter how the change is produced, the voltage will be generated. The change could be produced by changing the magnetic field strength, moving a magnet toward or away from the coil, moving the coil into or out of the magnetic field, rotating the coil relative to the magnet, etc.

Hydroelectric Energy

The water that is stored in the dam and this water when released flow through a penstock inside the dam.  A turbine propeller is fixed at the end of the penstock, and this gets turned by the force of the moving water. This converts the energy in the water into mechanical energy.  A Shaft from the turbine is connected to the generator which converts the mechanical energy into electrical energy thus generates electricity. This is based on the “faraday’s Principle”. The Electricity generated is carried from those generators to the homes and other places through the power line connected to them.

Hydroelectric Energy

Power Generating methods:

In many ways hydroelectric energy can be generated. They are as listed

  • Conventional methods

  • Pumped storage Systems

  • Run-of-the river method

  • Tide

  • Underground

Hydroelectric Energy

Conventional Methods:

This is the most common method of power generation where water in the dams is made to flow through the turbines that are connected to the generators to generate electricity.

The power extracted depends on the volume of the water and the difference in height between the source and the out flow.

Hydroelectric Energy

Pumped- storage Systems:

In a pumped storage method the water is made to move to the different reservoirs at different levels to meet demands.  When the demand for electricity is low such as during night times, the excess energy is used to pump the water to upper reservoirs and it gets released when the demand increases.

The actual mechanism is when the need for power arise the water stored in the upper reservoir is released into the underground tunnel. The water then moves through the intake tunnel. The force of water rotates the huge turbines that are connected to generators that produce electric power. The water then rushes through the discharge tunnel to the lower reservoirs.

Hydroelectric Energy

Pumped- storage Systems: (continue)

Pumped storage method was first used in 1890, Italy and Switzerland. In 1930 it was used in United States.

United States has the capacity to generate 3.003 MW energy, Guangdong and Huizhou Pumped storage station in Bath County Pumped storage station at china can generate 2,400 MW power, Okutataragi power station in Japan generates 1,932 MW electricity, Ludington station in United States.

Hydroelectric Energy

Run-of-the river method:

In these hydro electric stations they have small or no reservoir capacity so at the moment production happens in these power stations. The water flowing in the river or stream is made to flow through the turbines to generate power. This is subject to the seasonal factor as water may not be available throughout the year.

Belo Monte Dam, in Brazil has the capacity to produce11, 233 MW of power

Hydroelectric Energy

Tidal method:

As the name indicates it is a form of water energy which gets converted in to electrical energy. It is extracted from the day to day fall and rise of the water in the ocean and sea due to tides which rise and fall due to the gravitational pull of the moon and the sun.

When the tides rise and fall water is made to flow through the mouths of bays and narrow points. Turbines are placed in these places that generate electricity.

Only few tidal power stations are constructed. The first one to be onstructed was Rance Tidal power plant at La Rance, France. It has 240 Mw capacity. The Sihwa Lake tidal power Plant in south korea is the largest tidal power plant in the world.

Other types of Water Energy