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How Is Electricity Generated

Updated on August 3, 2015

How Is electricity actually produced?

Haven't you ever wondered how that powerhouse is able to generate electricity that lights up your home? Or how is that current captured and sent our way? Well, if you have, then you've come to the right place - this is a page about how the electric power is produced.

When I started learning mechanical engineering at the college, one thing I always wondered about is the actual process of converting the mechanical energy of water into electrical energy. I knew about turbines and tried to learn about generators and transmission lines, but couldn't understand. And in our 3rd year, we were given a chance to visit the largest hydro power plant of our country - where I learned A to Z about the process.

Lightning
Lightning | Source

Several Ways To Generate Current

Power generation is all science stuff - mostly physics and a little chemistry. So if you were or are not really into physics and the entire science thing, don't worry - I have made it easy enough to make the current generation process understandable.

There are numerous ways in which electricity can be generated. The power that comes to your home might have come from any of these methods or by the combination of these. The basic and the most common is through the flow of water, and this is called hydroelectricity.

  1. Hydro power (energy from flowing water)
  2. Solar (solar panels, solar cells)
  3. Steam (diesel power plants, concentrated solar panels by using power towers)
  4. Chemical (Batteries and Cells)
  5. Nuclear Reaction (by splitting Uranium atoms by a process called nuclear fission)
  6. Wind Turbines and Wind Charge

Water flowing down from a dam
Water flowing down from a dam | Source

How is Hydroelectricity Produced?

Hydropower plants consist of dam, runners, penstock pipes and a power house

Every powerhouse situated near the bank of a flowing river generates electricity through the help of a water turbine. A water turbine is simply a rotor that converts the flowing energy of water into rotational energy. This turbine is coupled to a large shaft, which in turn is coupled to a generator. When the water strikes the turbine, it rotates the turbine. This rotates the shaft which helps to generate electricity by a process called electromagnetic induction.

The generator thus generates electricity which is sent to sub-stations for converting the power into appropriate voltage and frequency.

Animated Video Showing The Production of Hydroelectricity

The Role of Dam

Dam forces the natural flow of water into an artificial path in such a way that its speed, impact energy and momentum increases and reaches its maximum value when it strikes the turbine. The normal speed of water cannot generate electricity sufficient for everyone.

Three Gorges Dam in China
Three Gorges Dam in China | Source
Tennesse River Dam in USA
Tennesse River Dam in USA | Source

They don't give us current, they give us power!

What the powerhouses actually supply is energy (or voltage or electric power) and not the conventional electricity or current. It is generated automatically because of the difference in energy or voltage. Electrons in the wires move towards higher voltage potential (or towards the energy source) and the current is opposite to their motion.

That's why it seems as if they are providing current.

Why Does Voltage Fluctuate?

The Role of Turbines

Turbines need to be maintained, repaired to increase their durability and last them longer. Every once in a while, a turbine can suddenly be stopped by limiting the amount of water flowing through it - due to which the voltage can fluctuate.

The same is when large industries suddenly start and stop consuming electricity. Such high power is not needed but the turbine keeps on rotating at the same speed for a certain amount of time. And until the turbine has been slowed (usually a few seconds), the voltage fluctuates badly, enough to damage your electronics!

Voltage fluctuations can also occur due to defects in wiring and due to lightning.

Wind Energy

Harvesting wind energy via turbines
Harvesting wind energy via turbines | Source

Electricity from Wind Turbines

  • The process of generating electricity from wind turbines is more or less similar to that of hydraulic turbines. Instead of water providing the kinetic energy necessary for the blades to rotate, wind (or air) does that work. The rotor of the wind turbine is also coupled with a generator which generates electric current.

  • In case of electricity through wind energy, the number of turbines (or rotors) required is too high than the same in case of hydraulic turbines. This is due to the fact that the speed of air at impact is less than the speed of water. Also, much wind energy exits the rotors as it enters without significant rotational effect. According to "Harvesting the Wind: The Physics of Wind Turbines", wind turbines can actually achieve a maximum efficiency of only 59% whereas turbines can achieve over 90%.

  • Generally, the power from wind energy is stored in batteries. It takes a lot of power for wind turbines for power transmission directly to cities and household.

You might want to see this informative "Three Gorges" documentary

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