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The Current Way of Generating Electricity

 

How electricity is normally generated

Currently, electricity is normally generated by transforming hydro power into electricity. The source of this hydro power is the movement of water (eg. water falls), which moves a turbine. This turbine is connected to an electricity generator. This generator transforms the kinetic energy of the moving water into electricity.

The word hydro itself came from a Greek word which means water. The first time water was used to generate electricity was in 1882. The water was from the Fox River in USA. The energy produced was enough power to light two paper mills and a house.

 

How this works

Water moves from a higher place to a lower place. This is one of nature’s laws which made generating electricity from hydro power possible. That's why dams or reservoirs have to be in a higher position than the turbine. Because if it's not, than there won't be any potential energy which will make the water fall, which means there won't be any kinetic energy to spin the turbine - everything won't work.

When the water falls, the potential energy of the water when it's up in the dam gets transformed into the kinetic energy of the falling water. This kinetic energy will then get transformed into electrical energy. The water has potential energy because of its position in the earth's gravitational field. The gravity is a force acting down on every object (including water) in another object's gravitaional field (like earth). After spinning the turbine the water goes back to the lakes or rivers, and get stored again in the dam, it gains its potential energy again and the cycle will keep on going. So we can see that in using hydropower, there are lots of energy transformation, and it works in a cycle - just like how it supposed to be according to the law of conservation of energy. Which states that energy can be neither created nor destroyed, it can only be transformed form one form to another.

When the water falls, it hits the blades of a turbine, this makes that turbine spin – the kinetic energy of the water makes the turbine spin. This movement of the turbine spins the generator (see figure 1). The generator has a set of magnets attached to it, which are called rotors. When the generator spins, this set of magnets rotates inside a stationary set of magnets (which is called the stator). This process produces a magnetic field, causing the electrons to jump from one atom to another. The "jumping electrons" is what we call electricity.

Figure 1

If the rotating speed of the rotor is steady, a steady flow of electricity will be produced in the stator. This is then connected to the electricity network through the transmission lines.

 

Natural water falls & DamsThe History behind Electricity Generation

For the natural water falls, the water falls naturally. For the dams, the water from the lakes, rivers, etc. is stored. And when there is enough water, the water is released - the valve at the bottom of the dam is opened to let the water flow. The water spins the turbine and then returns to the river.

Dams are made much thicker at the bottom to prevent the dam from collapsing, because the water pressure increases as you go deeper (see figure 2 below).

Figure 2

a hydro-electric dam

 

The History Behind Electricity Generation

Electricity generation was first developed by a famous English scientist, Michael Faraday in the early 1800’s. He found out that electricity could be produced through motion in a magnetic field. He discovered that when a magnet was moved inside a set of copper wire, an electric current is produced and flows through the wire.

Faraday’s electric dynamo was not very efficient (compared to our now); it provided only a small electric current. However, after 200 years, we are still using the same basic principles to generate electricity as Faraday’s electric dynamo – including in using hydropower.

Hydropower itself has been used by ancient people thousands of years ago to turn water wheels, to grind wheat into flour. And now we use it to generate electricity.

 

The Advantages of Using Hydropower

Some of the advantages we can get by using hydropower to generate electricity are:

- It's a clean source of energy, it doesn't create pollution

- Water is provided by nature and is renewable

- The cost is quite cheap compared to some other energy sources

- The dams can be recreational areas, which means more job - more income (eg. state rangers will be needed to take care of it)

 

The Disadvantages of using Hydropower

Despite the fact that hydropower is a good energy source it still has disadvantages. One of teh problems is the effects dams (which provide the water to spin the turbine) have on the ecosystems. Many rivers (before the dams were built) used to have spring floods that washed out river backwaters. When the dams were built, there were no more spring floods and that allows vegetation to block river backwaters. This kills many different kinds of fish that live in those areas. Also, if oils or chemicals mix with water running through the turbines, animals in the rivers will die. Another problem occurs in planning large dams. Large dams need large free areas. Many people have been evocated to make room for these areas. This is definitely not a good thing. Therefore, we are trying to find an alternate energy source, which has the same or more advantages but can fix up the disadvantages – and we chose solar power.

 

References


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Alternative Way

Last Modified 6/14/05 9:07 AM