Lesson video

Hello, my name's Dr.

George, and this lesson is called Energy Resources.

It's part of the unit Mains Electricity.

The outcome for this lesson is I can describe and compare different ways of generating electricity.

I'll be using these keywords, I'll explain them as we go along, but you can come back to this slide anytime if you need to remind yourself of the meanings.

The lesson has three parts.

They're called non-renewable energy resources, renewable energy resources, and sustainable energy.

So let's start by looking at non-renewable energy resources.

Energy resources are what we use to get the energy we need for transport, electricity generation and heating.

In the UK, we use most energy for transport.

Here's a pie chart showing our use of energy in this country in 2022.

So we have transport the most, then domestic, that's home energy use, industry, and finally, services, that would include shops and the NHS, for example.

And the main energy resources we use include fossil fuels, that's coal, oil and natural gas, nuclear fuels, uranium and plutonium, wind power, solar power, hydroelectricity, tidal power, water waves, biofuels and geothermal power.

And I'll be saying a little bit about each of these in this lesson.

Some energy resources are renewable energy resources and that means that they can be replenished as we use them, so there's always more of them.

Many renewable resources replenish themselves.

For example, wind.

Others usually need to be replenished by us.

So biofuels, for example, which come from plant matter, we'd need to plant more to get more of it.

Fossil fuels and nuclear fuels in particular are non-renewable energy resources.

They aren't replenished as we use them and they will run out eventually.

So which of the following energy resources are non-renewable? And each time I ask you a question, I'll wait five seconds, but if you need longer, press pause and then press play when you have your answer ready.

And the non-renewable resources here are natural gas, which is a fossil fuel, and nuclear fuels.

Nuclear fuels will last a long time at the rate we're using them, but not forever.

Coal, oil and natural gas are all fossil fuels and they were formed hundreds of millions of years ago from plants and animals that were buried under sediment, that's materials that fall to the bottom of a river or sea.

And that sediment later became rock.

And then high pressure and heat over long periods of time changed the chemical composition, the chemical makeup of these buried plants and animals.

And we call this process fossilisation.

And tiny fossilised sea creatures became a mixture of hydrocarbons, that's substances that are made up of hydrogen and carbon atoms bonded together, that we call oil and natural gas, while fossilised plants became a black rock made mostly of carbon, that we call coal.

Coal used to be burned in homes to heat them.

And many modern homes now burn natural gas in a gas boiler that heats water that goes around the radiators in the home, heating the rooms, and we call this central heating.

Meanwhile, oil is not of use as it is when it comes out of the ground, but it can be split into useful components called fractions.

And these include petrol and diesel for road and rail transport, and kerosene, which is a fuel for aeroplanes.

So, how did fossilisation change plants and tiny sea creatures into fuel? And the only correct answer here is it changed their chemical composition.

Now, fossil fuels are burned in vast quantities in power stations to generate electricity.

So the burning of the fossil fuels is used to heat water and then turn it into steam.

And that fast moving steam is used to turn turbines, which look a bit like wind turbines.

And those turn huge electrical generators generating electricity.

In this photo of a fossil fuel power station, we can see emissions from burning, and that would include carbon dioxide and particulates, small pieces of solid, like soot.

And we can also see clouds of tiny water droplets from cooling towers.

So not all of this is pollution, some of it is water.

And the electrical generators are in these buildings here.

Burning gas produces fewer particulates than burning coal or oil.

And nuclear fuels are also used in nuclear power stations to heat water, turn it into steam turn turbines, which spin electrical generators.

There's a nuclear reactor here in this photo.

And the electrical generators are in this building here.

And these clouds are just tiny water droplets from cooling towers, so nuclear power stations don't emit carbon dioxide.

And nuclear reactions cause a lot of heating from just a small amount of fuel, much smaller amount than you would need from say, coal.

But there are some waste products that are radioactive that makes them dangerous to humans and other.

That makes them dangerous to humans and other living things, so they need to be stored well out of the way kept safe where humans can't go near them for thousands of years.

Which of the following types of pollution do nuclear power stations produce? And the only one of these that's correct is radioactive waste.

They don't produce carbon dioxide or particulates, like soot.

And now I'd like you to try comparing the generation of electricity by fossil fuels with a generation of electricity by nuclear fuels, so think about things that are common to both of these.

There's a box for that in the middle.

And then things that are true for fossil fuels only and for nuclear fuels only.

Press pause while you jot down your answers and press play when you're ready to check them.

So here is some of the things that you could have said.

Starting in the middle with fossil fuels and nuclear fuels, both heat water into steam, which is used to turn turbines that spin electrical generators.

And both use cooling towers that give off lots of clouds of tiny water droplets to cool the steam back to water.

And then fossil fuels only, huge amounts of fuel are needed and lots of carbon dioxide gas is produced.

Also, burning coal and oil makes lots of particulates, soot.

And then nuclear fuels only.

Small amounts of fuel are needed and the radioactive waste produced needs to be stored safely for thousands of years.

So, well done if you came up with a lot of those points.

Next, let's take a look at renewable energy resources.

One example is wind turbines and they can be used to spin electrical generators to generate electricity.

In the top of each wind turbine, there is a small electrical generator.

And here's a picture on offshore wind farm, so wind turbines situated out at sea.

About 30% of electricity in the UK is generated using the wind.

There are no costs of fuel and there are no emissions from wind turbines, but the power generation varies depending on the weather, depends on how fast the wind speed is.

Another type of renewable energy resource is solar.

And solar panels like these can convert radiation from the sun into electricity.

On the left is a solar farm, a large number of solar panels in a field.

And on the right, solar panels on house roofs.

Nearly 5% of electricity in the UK is generated using the sun.

And solar panels give off no emissions, although, of course, it requires resources to make them, as for wind turbines.

But the power generation again, varies depending not only on the weather, whether it's cloudy, but also on the location and the time of year because it's affected by the length of the day and how high the sun is in the sky.

Which of the following days would generate the most electricity from a solar panel? And the correct answer is a sunny day in the autumn because the sun is in the sky for longer in autumn than in winter.

And, of course, there's more sunlight on a sunny day than a cloudy day.

Electricity can also be generated using the energy of falling water.

Here's a picture of a hydroelectric power station, hydro means water.

And it usually would use a dam like this to create a high reservoir of water.

So this is a dam along a river.

And so the water from the river is built up behind the dam to create this artificial lake or reservoir.

The water is then allowed to fall through gaps in the dam where there are turbines, a bit like a wind turbine, but underwater.

And the falling water turns the turbines and that spins electrical generators.

There are no fuel costs and there are no emissions when you use hydroelectricity and it can generate electricity very quickly when needed.

But building the dam can destroy habitat by flooding because what used to be behind that dam was a river and now there's a deep lake.

And that will have destroyed the habitats of plants and animals that used to live in or near the river.

Electricity can also be generated from tides, the movement of the sea in and out from the shore.

And that uses a barrage, a sort of barrier that's built across the mouth of a river estuary, so a place where a river empties into the sea.

The barrage allows water to fill up the river estuary at high tide, so the water level builds up and then the barrage closes.

At low tide, water is let out to sea through turbines that spin electrical generators.

This way of generating electricity is very reliable because there are always too high tides every day, and it doesn't depend on the weather, and it also doesn't produce any emissions, no carbon dioxide or pollution.

However, a barrage can block access to ports for shipping and it can also damage estuary habitats, which often support a variety of plant and animal life.

Is this statement true or false? It takes just a few minutes to turn on a hydroelectric power station to generate electricity? Think about what you've learned about hydroelectric power, choose true or false, and then explain why you chose that answer.

Press pause while you're thinking about this and press play when you're ready.

This is true.

To start electricity generation in a hydroelectric power station, all that needs to be done is to open a valve to allow water to fall through a turbine that's connected to an electrical generator.

So nothing needs to heat up or start burning and there's no reliance on the weather or the tides either.

So this can be started very quickly.

Electricity can also be generated from the up and down movement of water waves.

So you can get a kind of generator that rests on the sea, is moved up and down by the waves, and that generates electricity.

These are not very common, but they do exist.

There are also biofuel power stations.

These generate electricity by burning, but not burning fossil fuels, burning plant material such as crops that have been grown specially for this.

They do cause some pollution, but when the next crops are grown, they absorb carbon dioxide as they grow, so biofuel power stations can be almost carbon neutral.

Geothermal power stations make use of rocks underground that are naturally hot, and they use this to heat water, turn it into steam, turn turbines, which spin electrical generators.

This isn't used very much at the moment in the UK, but it's used a lot in places such as Iceland.

Which of the following renewable energy resources emits pollution when used to generate electricity? The answer is biofuels.

And now, I'd like you to try to identify some advantages and disadvantages of using each of the following four resources for generating electricity.

You don't have to write your answers in full sentences as long as your points are clear.

So press pause when you do this and press play when you're ready.

And here are some of the things that you might have said.

For wind power advantages, no fuel costs, no polluting emissions.

Disadvantages, output varies depending on wind strength and weather conditions.

Solar power.

Advantages are no fuel costs and no polluting emissions.

Disadvantages, include that the output varies depending on the weather and the time of year.

Hydroelectricity has also no fuel costs and it's reliable.

It can be turned on quickly when needed, but it causes damage to habitats and it's very expensive to construct the dam in the first place.

Biofuels have the advantage that growing crops doesn't need lots of construction.

There's no big expensive project to start this up, but it pollutes when it's burned and it leaves less space to be able to grow food.

So, well done if you thought of some of those.

Now let's think about sustainable energy.

In 2023, about 40% of the electricity in the UK was generated is in renewable energy resources.

Compare that to 2000 when just 3% of energy was generated in this way.

However, generating electricity only accounts for about 20% of the total energy resources we use in this country each year.

The largest use of energy resources is actually for transport, and over 90% of cars on the road are still burning petrol or diesel.

So sustainable energy doesn't mean simply renewable energy.

It means using energy resources in a way that will allow people in the future to have sufficient energy for their needs.

So it's thinking about being able to keep going like this into the future.

Non-renewable energy resources won't last forever.

And burning fossil fuels causes pollution that harms people's health and also produces carbon dioxide that contributes to global warming, climate change.

Reducing our dependence on non-renewable energy resources is a positive step towards a more sustainable future.

So it's part of what we need to do to make our energy use more sustainable.

So what's meant by sustainable energy? It's actually B, using energy resources so that people in the future will have enough for their needs.

And there's no simple answer to how we can make sure we have sustainable energy and there's no single energy resource that can meet all of our needs.

This leaves us with more questions.

How do you weigh the advantages and disadvantages of each type of energy resource? And who should decide which energy resources to use and how they should be used? And finally, what should be done if people object to say, a large wind farm being built near them, even if it benefits many more people elsewhere? Now a question for you.

True or false, scientists alone can develop sustainable energy? Decide whether you think it's true or false and then explain your choice of answer.

So did you choose false? And the reason is that some decisions don't just rely on facts that are either correct or incorrect, but also on people's opinions.

However, science does help ensure that decisions are based on accurate facts and proper understanding.

Now, here's a task for you.

Imagine that there are plans to build a wind farm of 300 wind turbines just off the coast of a popular seaside resort.

I'd like you to describe some advantages of building the wind farm and some disadvantages of building it.

And then state whether you think the wind farm should or should not be built and explain why.

So press pause while you do this, and press play when you're finished, and I'll show you some example answers.

So here are some of the things that you could have included.

The wind farm would provide electricity without harmful emissions.

Once constructed, it's inexpensive to operate.

It could replace other polluting methods of generating electricity and helps reduce climate change.

Disadvantages, the wind farm is expensive to build, many people consider it unattractive and it might discourage visitors from coming to the resort.

It could also then negatively impact local businesses who might rely on tourism for their income.

And then choosing what to do.

Well, there is no right or wrong answer about whether the wind farm should be built.

It's depends on which reasons you think are the strongest.

In reality, other options will also be considered, and the choice is usually the one that causes the least harm while offering the most benefit.

So, well done if you made some of those same points.

And now we've reached the end of the lesson, so here's a summary.

Renewable energy resources can be replenished as they're used up and non-renewable energy resources cannot.

Fossil fuels, that's coal, oil and natural gas, and nuclear fuels, uranium and plutonium, are non-renewable energy resources.

Wind power, solar power, hydroelectricity, tidal power, water waves, biofuels and geothermal power are renewable energy resources.

And sustainable energy means using energy resources in a way that will allow people in the future to have sufficient energy for their needs.

Well done for working through this lesson.

I hope you found it interesting.

There are a lot of important points here that will matter in your future.

I hope to see you again in a future lesson.

Bye, for now.