3-4 Electrical Energy Generation

Where does electrical energy come from?

When you turn on a light switch, you probably don't think about how the energy coming out of a light bulb is generated, or made. However, it doesn't just come from nowhere: it had to come from some other type of energy. We summarize this using the First Law of Thermodynamics:

This means a few things for the light bulb:

1. The light (and heat) coming out of the light bulb was originally a different type of energy: in this case, electrical energy carried by the current in the wires.

2. That electrical energy was once another type of energy.

3. Whatever that original energy was, it had to come from somewhere else.

4. The light (and heat) coming out of the light bulb doesn't just vanish: it goes out into the room, then out through the walls, into the Earth or atmosphere, and eventually out into space.

What we will be looking at here is the part that deals with where the energy came from before it became electrical energy in your wires.

Turbines

Most forms of energy generation involve some sort of turbine: a device that turns the motion of a liquid or gas into electrical energy.

Here is a short video which describes how turbines in general work. This was made by a company which generates electricity in the north-central United States.

As the video suggests, turbines are involved in a lot of different types of energy generation.

Non-Renewable vs. Renewable

The ways we generate electricity can be broken down into two main categories.

Traditionally, we have used a lot of non-renewable ways to generate electricity. This means that the source of the energy is used once, and then it is gone forever.

As we progress through the 21st century, we are increasingly using renewable sources of energy to generate electricity. This means the source of the energy regenerates itself without us having to do much, if anything. It also means there is little to no impact on the environment.

Here's a desciption about how the two main types of energy generation compare:

What almost all forms of energy generation have in common is this basic transformation:

some other form of energy → spinning turbine → electrical energy

There is one main exception, as you will see.

Non-Renewable sources

The two main sources of non-renewable energy are:

• fossil fuels (such as coal, oil and natural gas)

• nuclear energy

This article nicely describes how these two main sources of energy work. As you read the article, answer the following questions:

• What does the word "fossil" mean here?

• When did the living things that became fossil fuels live?

• What type of energy did these living things take in, originally?

• Name two types of fuel that can be made from oil.

• What is another name for "natural gas?"

• Which state of matter (solid, liquid or gas) is coal?

• What is the main element used in nuclear energy production?

• What percent of our global energy comes from non-renewable sources?

• Are fossil fuels generally cheap or expensive?

Make a chart like the one below, and fill it in with a few of your own words from this article, or another reliable internet resource.

Renewable sources

There are several renewable sources of energy, and they are growing in popularity. One of the main reasons they are growing is because the price of a lot of them has gone down in recent years: some are even less expensive than non-renewable sources.

Here are some renewable sources of energy:

• wind

• solar

• geothermal

• biomass

• hydroelectric

Make a chart like the one below, and fill it in using information from this article or other reliable sources online.

Tidal/ocean power... not quite ready yet?

Very famously, in the Bay of Fundy in eastern Canada between Nova Scotia and New Brunswick, the ocean level rises and falls a LOT, twice a day. This happens because of the spin of the Earth and the gravitational pull of the moon.

This means that a very large amount of water is sloshing around, very predictably, twice a day. Why not try to take the energy of this moving water and turn it into cheap, renewable energy? As it turns out, we've tried... and it's harder than you think.