Generating electricity

By Moira Whitehouse PhD

ElectricitySo usefulSo scary

How is it generated?

Let’s look at how electricity, one form of energy is generated.

But remember, energy cannot be created or destroyed. It can only be transformed from one type to another. This means that to generate electricity, we have to use another kind of energy to fuel the process- in this world you just don't get something for nothing!

An electrical generator is made up of the following parts: a strong magnet and copper wire that turns inside the poles of the magnet.

A simple electrical generator

A magnet with north and south poles

The wire turning

Electrons flowing

To cause electrons to flow through the wire, we must have something to spin the loop of wire.

What kind of energy is motion?

So to get electrical energy from a generator we must have ______________ energy.

With this generator what provides the mechanical energy?

What about here?

How would you like to turn the wire to generate all the electricity you use?

Yes, steam is often used to turn a blade shaft called a turbine which then turns the wire inside the magnet generating electricity.

turbine

water being heated to make steam

turbine turning the wire inside the magnet

a transformer to make the electricity less strong

Wires to take the electricity to our homes

steam turning the turbine

Now we have to find something to heat the water to make steam.Most often either coal or natural gas is burned to heat the water changing it to steam.The steam turns the turbine which turns the wires inside the generator producing electricity.

Here is a power station that burns coal to generate a flow of electrons in a wire which travels to a house through power lines.

When coal or natural gas is burned to generate electricity____________ energy is changed to ____________ energy to electrical energy.

Sometimes nuclear energy is used to heat the water to make steam that turns the turbine.In this case, _________ energy is changed to ___________ energy to _________ energy.

Most power plants need steam to generate electricity. The steam rotates a turbine that activates a generator, which produces electricity. Most power plants still use fossil fuels to boil water for steam. Geothermal power plants, on the other hand, use steam produced from reservoirs of hot water found a couple of miles or more below the Earth's surface to drive the turbines.

If you drill deep down into the Earth's crust, the temperature rises dramatically..

Deep underground in these hot rocks are pools of hot water and steam. When released this steam has tremendous amounts of energy and can be used to turn a steam turbine.

Pools of hot water and steam

Steam rising in pipe

A few power plants do not use steam to turn the turbines. Wind pushingthe blades of a windmill can cause the turbine to rotate.

In other plants, flowing water in a river or waves in the ocean can be used to turn a turbine to generate electricity.

Here flowing water held back by a dam on the river is powering the turbine.

In this instance, the motion of the waves forces air in and out of a chamber which then turns the turbine.

Photovoltaic solar cells directly convert sunlight into electricity.

http://www.childrensuniversity.manchester.ac.uk/interactives/science/energy/electricity/

At this link you can find an animated slide show illustrating examples of energy resources used to generate electricity.

What other energy resources that do not use steam can be used to turn the turbine inside the generator?

On your paper, draw a picture of a simple electrical generator. Label the parts and explain how it works.Steam is usually used to turn the turbine. List the energy resources that can be used to heat water making steam to turn the turbine inside the generator.

What energy resource does not need a generator and can be directly converted into electricity?