Lesson video

This lesson is called Energy Resources and is from the unit Mains Electricity.

Hi there.

My name's Mrs. McCready, and I'm here to guide you through today's lesson.

So thank you very much for joining me today.

In our lesson today, we're going to describe and compare different ways of generating electricity.

And we're gonna come across a number of keywords today, and they're listed up here on the screen for you now.

You may wish to pause the video and make a note of them, but I will introduce 'em to you as we come across them.

Now, in our lesson today, we're going to, first of all, look at non-renewable energy resources.

Then, we're gonna consider renewable energy resources before we finish our discussion by looking at sustainable energy.

So are you ready to go? I certainly am.

Let's get started.

Now, energy resources are what we use to get the energy that we need for many different things, including transport, electricity generation, and heating.

Now, most of the energy that we use in the UK is used for transport, for moving us or goods around the country.

So 41% of the energy consumption in the UK in the year 2022 was used for transportation.

26% was used domestically in our homes.

17% was used by industry.

And 16% was used by services, and that would include shops, businesses, schools, hospitals, those sorts of things.

Now, in order to get that energy, we have a number of energy resources that we can use, and these include fossil fuels, such as coal, oil, and natural gas, nuclear fuels, including uranium and plutonium, wind power, solar power, hydroelectricity, which is about using water to provide electricity, tidal power, water waves, biofuels, and geothermal power, which is about using the earth's heat to provide energy.

Now, some of those resources are renewable energy resources, and renewable energy resources will either not run out or we can replenish them as we use them.

So for instance, wind will never run out.

And so that is a renewable energy resource, whereas biofuels taken from burning wood, wood pellets, bark, that sort of thing, that's also a renewable energy resource, but it requires replenishment.

So as we cut down trees to use them for biofuels, we would then need to replenish them, replace, replant those trees in order to grow the fuel again to be able to burn more.

In contrast, some of the energy resources that we use are non-renewable.

For instance, fossil fuels and nuclear energy are non-renewable.

This means that they will run out and they cannot be replenished.

So which of the following energy resources are non-renewable: hydroelectricity, natural gas, nuclear fuels, and wind? I'll give you five seconds to think about it.

Okay, so you should have chosen natural gas and nuclear fuels as examples of non-renewable energy resources.

Well done.

So coal, oil, and natural gas are fossil fuels.

We've already seen that.

And these were formed hundreds of millions of years ago from plants and animals that were buried in sediment, which then was later turned into rock.

So what happened is these animals and plants died and then were buried.

And over the course of a very long period of time, several million years, the action of high pressure and heat on that sediment changed the chemical composition of that sediment and turned it into rock.

So those buried plants and animals were fossilised in this process using high pressure and heat.

And some of those fossilised sea organisms became a mixture of hydrocarbons that we call oil and natural gas, whereas others became black rock called coal, and that is almost exclusively carbon.

So organisms that lived hundreds of million years ago are providing us with energy now in the form of coal, oil, and natural gas.

But these levels are finite.

The amount of coal, oil, and gas that we have on earth is finite, and it, therefore, will run out, which is why it is considered a non-renewable energy resource.

Now, we can heat our homes with coal.

We can burn it in our fireplaces for instance.

And certainly traditionally, that was used a lot across the UK to heat homes.

Nowadays, many homes use natural gas in a gas boiler as part of their central heating system to heat the home.

And other fractions of oil are used for other purposes, such as petrol and diesel to run our cars, and rail transport, and kerosene, which is used for air transport.

So these non-renewable products can be used in lots of different ways to provide energy for our daily activities.

So how did fossilisation change plants and tiny sea creatures into fuel? Did it, A, change their chemical composition? Did it, B, turn them into stone? Or, C, preserve them underground? I'll give you five seconds to think about it.

Okay, hopefully you said A, that it changed their chemical composition.

Well done.

Now, when we are using fossil fuels to generate power, we burn vast quantities of them in power stations, and this generates electricity because what happens is when they are burning, they heat water, and they turn water into steam, and then the steam is used to turn turbines, which allows electricity to be generated through huge electrical generators.

So if we look at the photograph here on the screen of a fossil fuel power station, we can see emissions coming outta the tall chimney stacks from where the fossil fuels have been burnt, and this is carbon dioxide and other particulates, which are being released into the atmosphere as a result of them being burnt.

We can also see how tiny droplets of water are being released from the cooling towers, which are used to cool the water down so that it can be recycled through the system.

We can also see the yellow boxes, which are the electrical generators, where the electricity is actually being generated as a result of this process.

And these are all processes that are happening within the fossil fuel power station.

Now, the same kind of process is happening within an oil power station or a gas power station, but the difference is that burning gas produces much less of the sooty particulates into the atmosphere than coal does.

So coal's quite a dirty fuel.

It not only produces a lot of carbon dioxide into the atmosphere, but it also releases a lot of soot and other particulates as well.

So it's very filthy, whereas gas is much cleaner in comparison.

Another way of producing electricity is to use nuclear fuel.

Now, nuclear fuel is also considered a non-renewable energy resource, and it's used in much the same way as coal, oil, and gas because the heat generated by the nuclear reactions happening within the fuel is enough to heat water into steam, and the steam is then passed through the turbine, which turns the generator to generate electricity.

So if we look at the nuclear power station photograph here, we can see the nuclear reactor in the back there where the nuclear fuel is providing heat to heat the water into steam.

We can also see the large grey boxes where the electrical generators are present.

That's where the electricity's actually being generated.

And we can also see the clouds of water where water is cooling down back into clouds into a liquid form from the cooling towers, and that's just cooling down the water and allowing it to be recycled through the system.

Now, nuclear reactors are much, much cleaner than burning coal, oil, or gas in the sense that they don't release sooty particulates into the atmosphere, and neither do they release carbon dioxide.

However, they do produce a lot of nuclear waste at the end of the lifecycle of the fuel.

And nuclear waste is highly radioactive and needs extremely careful storage for many, many thousands of years whilst it continues to emit radiation.

So whilst nuclear fuels are clean in terms of carbon dioxide release, they are certainly not clean in terms of the other types of waste that they produce.

So which of the following types of pollution do nuclear power stations produce? Carbon dioxide, particulates, or radioactive waste? I'll give you five seconds to think about it.

Okay, so you should have chosen radioactive waste as the type of pollution made by nuclear power stations.

Well done.

What I'd like you to do now is to compare and contrast the generation of electricity by fossil fuels with the generation of electricity by nuclear fuels.

So you can see on the screen there, there are three columns.

The one on the left deals with fossil fuels, so the things which are specific only to fossil fuels.

The column on the right is specific to nuclear fuels, so things that are specific only to nuclear fuels.

And the column in the middle is for similarities between fossil and nuclear fuels.

So consider the differences and the similarities, and make your notes into the three different columns.

Pause the video and come back to me when you are ready.

Okay, let's see what you might have written.

So for features specific to the fossil fuels, you may well have said that firstly, huge amounts of fuel are required in order to produce electricity, that lots of carbon dioxide gas is produced as part of the burning process, and that burning coal and oil makes a lot of sooty particulates, which are also released into the atmosphere.

So they're quite dirty.

For features that are specific to the nuclear fuels, you may well have said that small amounts of fuel are needed, unlike fossil fuels where large quantities are required.

You should also have included the fact that radioactive waste is produced, and this needs to be stored safely for thousands of years whilst it continues to be radioactive.

And then as a comparison between the two on the similarities, you should have said that they both heat water into steam, which is then used to spin a turbine to generate electricity in the electrical generators, and that they both use cooling towers in order to cool that water down to allow it to be recycled through the system, and this gives off lots of clouds of tiny water droplets, and allows the steam cool back into water.

So just review your comparison.

Did you get all of those similarities and differences listed? Well done, if you did.

Do include anything else that you might have missed.

Okay, let's have a look now at renewable energy resources.

Now, there are a number of different renewable energy resources available to us, and they've all got pros and cons associated with them.

So let's have a look at them in a bit more detail.

So some renewable energy resources generate electricity by using either wind or water to spin the turbine directly.

So if we look at the wind turbine in the picture, we can see that it has turbine blades, which are connected to an electrical generator, and the wind turns the turbine, which allows electricity to be generated by the electrical generator.

And essentially, this is the same process that is going on within a nuclear or a fossil fuel power station, except instead of having to heat water in order to generate steam to turn the turbine, the wind is turning the turbine directly.

So it misses out that heating of water step, but the rest of the process is more or less the same.

Now, wind turbines produce electricity using electrical generators on the top of each one of them.

Here's an example of an offshore wind farm with many, many turbines across a large space, each of which has an electrical generator on the top of it connected directly to the turbine blades.

And about 30% of the electricity produced in the UK is generated using wind farms, either onshore on land or offshore as shown in the picture.

Now, the benefits of wind-generated electricity is that there are no fuel costs.

It doesn't cost us to use the wind in order to generate this electricity.

And also there are no emissions, no carbon dioxide is released into the atmosphere.

No particulates or anything like that are released into the atmosphere in order to generate the electricity using the wind.

However, as you know, wind does not always blow and neither does it always blow at the same speed.

And so the amount of electricity that can be generated by a wind turbine can vary greatly depending on the wind speed and the weather conditions.

Electricity can also be produced using falling water, and, again, falling water will turn turbines to generate electricity.

Now, used in this form is called an hydroelectric power station, and a hydroelectric power station is created by putting a dam in the way of a river, and that causes a backlog of water behind the dam, this large reservoir of water.

And then the water flow through the dam can be highly controlled because as the water is falling through the dam, it's turning turbines, much like the wind turns the turbines in the wind turbine.

So the water falling through the dam turns turbines, which generates electricity through the electric generators.

Now, again, there are no fuel costs with storing the water and using it in this way.

And also there are of course no emissions either.

No carbon dioxide is released into the atmosphere in this process.

It's also extremely responsive as a method of producing electricity because with one flick of a switch, electricity can be turned on from no electricity being generated to quite a significant amount of electricity being generated.

And in fact, hydroelectricity is often used to respond to sudden surges in electricity demand, such as when the advert break comes on during a TV programme which many people are watching and everyone goes into the kitchen and turns on their kettles to boil their water for their cup of tea.

So this sudden a surge of occurs, and that is responded to using hydroelectricity usually.

So it's highly responsive and very flexible.

However, building a dam across a river has significant environmental implications because it will destroy significant amounts of habitat upstream and also potentially downstream, as well, of the dam because of the flooding and then the lack of water further downstream.

So environmentally speaking, hydroelectricity can be quite problematic, but in terms of carbon dioxide and the greenhouse effect, they're very, very clean.

So it takes just a few minutes to turn on a hydroelectric power station to generate electricity.

Is that true or false? What do you think? Okay, that is true, but can you explain your answer? So you should have said that to start electricity generation in a hydroelectric power station, all that needs to be done is to open a valve to allow the water to fall through a turbine that is already connected to the electric generator.

And so yes, it really only takes a few minutes to turn on a hydroelectric power station.

Well done.

Now, there are other forms of electricity generation in the renewable energy family including using tidal barrages.

Now, a tidal barrage is built across the mouth of a river estuary.

And what happens is that essentially it's a bit like a dam.

It allows water to fill up behind it at high tide, and then it closes and traps that water behind it.

The water then recedes into the open sea, but is trapped upstream.

And then when required, the water is then let out at low tide through the tidal barrage.

And that, just as with the hydroelectric power station, as the water is flowing through this barrage, it is turning turbines, which is generating electricity through the generator.

So using high tide to move water is quite efficient because the water is moving anyway, and then stopping it from flowing back again into the open sea using the tidal barrage means that its movement back into the open sea can be controlled and used to produce electricity.

Now, these are highly reliable because there are two high tides every day.

So we know when electricity can be generated, and we know at what times of day that's going to happen.

However, just like building a dam, because the tide barrage blocks the access to the river, it can have significant implications, including environmental implications through habitat destruction and also implications about traffic through the port and along the river, because essentially what you're doing is blocking the river.

And so you are stopping the access in and out of the river by ships and so reducing the ability for a port to function effectively.

So they're very, very reliable.

Of course, they're green in the sense that they don't produce carbon dioxide emissions into the atmosphere, but they do have some significant implications.

So they have to be installed with great care and consideration about what else is going on around that area, both in terms of human activity and also in terms of environmental impact.

In a similar way, electricity can also be generated by using the movement of waves.

So water waves are generated by the wind.

As the wind blows, it stirs up the water in the seas, and that causes water waves.

And putting water wave converter into that space means that as the water is moving up and down with the wave action, it can generate electricity by again turning turbines which generate electricity.

So again, the same principle is being applied, just in a slightly different way.

However, waves are generated by wind, and wind is not a consistent feature on the earth, and, therefore, generating electricity using waves is not a reliable nor even a predictable way of generating electricity, unlike the tidal barrage.

So why is a tidal barrage more reliable than a wave energy converter? Is it because, A, it is larger and generates more electricity, B, there are always two tides each day, or, C, it generates electricity continuously? I'll give you five seconds to think about it.

Okay, so hopefully you chose B, that there are always two tides each day.

Well done.

Now, we saw that when we were looking at fossil fuels and nuclear fuel that they are using heat to turn water into steam, and the steam is then driving turbines, spinning turbines, which is then generating electricity.

Now, biofuel power stations work in same way as fossil fuels and nuclear power stations in that they are burning crops to heat water to turn water into steam, which is then used to turn a turbine to generate electricity.

And so the rest of the principle is the same.

Now, because they are burning crops, they are generating pollution, including releasing carbon dioxide into the atmosphere.

However, they are called renewable, and they're considered a lot greener than fossil fuels because in order to provide crops for the biofuel power station, the crops have to be grown in the first place.

When the crops are growing, they are absorbing carbon dioxide outta the atmosphere.

And then when they're burnt, that carbon dioxide is being rereleased back into the atmosphere.

So there's a very short cycle going on with carbon dioxide being absorbed into the plants whilst they're growing and then being released back into the atmosphere again when they're burnt.

And this means that they are almost carbon neutral, not entirely, but very nearly, almost carbon neutral.

But otherwise, the principle of a biofuel power station is exactly the same as using fossil fuels.

Another form of using heat to turn water into steam is to use the heat of the earth.

Geothermal power stations do exactly this.

Now, these are quite common in places where geothermal activity is very easy to access, such as in Iceland.

And geothermal power plants use the heat from the earth to heat water up to turn it into steam, and then the steam turns the turbines, which generates electricity.

So you can see how turning turbines to generate electricity for all of these processes, for all of these different power stations is fundamental.

Just how the turbine is turned is the thing that differs, what it is that's causing the turbine to be spun, whether it's water, wind, or steam.

And that depends on the type of power station being used.

But, again, geothermal power stations are highly eco-efficient in the sense that they are using earth's heat, heat that is already being produced by the earth to turn water into steam.

And so there is no carbon dioxide release happening as part of this process, and electricity is, therefore, being generated very cheaply and greenly as well.

So which of the following renewable energy resources emits pollution when used to generate electricity: biofuels, geothermal power, or wave power? I'll give you five seconds to think about it.

Okay, you should have said biofuels are the form of renewable energy resource that emits pollution.

Well done.

Now, we've looked at a whole range of energy generation methods that use turbines to turn generators to produce electricity, but there is one form of electrical generation which does not use that principle at all, and that is using solar panels.

So solar panels, whether they're fitted on top of your roof or fitted within a solar farm, doesn't matter where they are, they convert radiation from the sun into electricity directly.

They don't need to use turbine in order to generate electricity.

The electrical conversion happens straight away within the solar panel itself.

Now, 5%, nearly 5% of electricity in the UK is generated using sun through solar panels.

And these are, again, very efficient, give off no emissions, but their power generation is again very variable.

Of course, no power generation is generated at night because there's no sun.

So they are very much limited during daylight hours.

And, of course, on cloudy days, the amount of electricity that can be generated is much reduced because the cloud is obscuring the sunlight.

So the amount of energy which is generated through solar panels is very flexible, very variable, and entirely unpredictable as well.

And it depends on many factors: weather conditions, the location, the time of year.

So solar panels are very efficient at converting energy from the sun into electricity, but they aren't terribly reliable.

So which of these days would most electricity be produced by a solar panel: A, a sunny day in the autumn, B, a sunny day in the winter, C, a cloudy day in the autumn, or, D, a cloudy day in the winter? I'll give you five seconds to think about it.

Okay, you should have chosen A.

A sunny day in the autumn is when most electricity will be produced by a solar panel.

Well done.

Right, we've had a pretty detailed view of advantages and disadvantages of a huge range of renewable energy resources.

So what I'd like you to do is now distil that into a summary table, but I want you to specifically focus on energy resources of wind, solar, hydroelectricity, and biofuels.

And I'd like you to list advantages and disadvantages of each of those four resources for generating electricity.

So pause the video, and come back to me when you're ready.

Okay, let's have a look at what you might have included.

So for wind power, you should have included the fact that there are no fuel costs and no polluting emissions, but the output varies depending on wind strength and the weather conditions.

For solar power, you should have included the fact that also there are no fuel costs and no polluting emissions.

However, the disadvantages are that the output varies depending on the weather and the time of year.

For hydroelectricity, the advantages include that there are no fuel costs, it's highly reliable, and it can be turned on very quickly when needed.

But the disadvantages of hydroelectricity are that it can cause damage to habitats through flooding, and they are very, very expensive to construct.

And then the last energy resource, biofuels, the advantages include that growing crops does not need a lot of construction in order to happen, but the disadvantages is that it releases pollution when the crops are burnt, and that by growing crops for burning, there is less space to grow crops for food.

So just review your work over.

Did you include all of those advantages and disadvantages? Make any further amendments that you need to, and well done indeed.

That was quite a detailed summary there.

Okay, now let's look at the last piece of our lesson about sustainable energy.

In 2023, about 40% of the electricity in the UK was generated using renewable energy resources, such as wind, solar, and hydroelectricity.

Now, this compares very favourably to just 3% of electricity being generated in this way in the year 2000.

So in the course of 23 years, a 37% increase in the amount of electricity that's generated through renewable sources has been achieved.

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

So 80% of the energy requirements that we as a nation have do not get fulfilled through electricity.

And the largest use of energy in the UK is for transport.

Over 90% of the cars on the road burn petrol or diesel.

And this is an enormous source of energy requirement, and it is also an enormous source of use for non-renewable energy resources.

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

In other words, not using it all up now and not leaving anything for our future generations.

Now, non-renewable energy resources, which will not last forever and are not replenishable, such as fossil fuels and nuclear fuel, are obviously not sustainable because we are currently using them up and we're also producing pollution, which is harming people's health now and also contributing substantially to global warming and climate change.

So using non-renewable energy resources is really problematic because of the significant and range of implications that it has, both for our future populations and also for our existing population.

So we need to move towards a much more sustainable energy use model and reduce our dependence on non-renewable energy resources.

But that's quite a challenge in order to achieve.

So what is meant by sustainable energy? Is it, A, energy that can be replenished as we use it? Is it, B, using energy resources so people in the future have enough for their needs? Or is it, C, using fewer non-renewable energy resources so they last for much longer? I'll give you five seconds to think about it.

Okay, so you should have said that sustainable energy means using energy resources so that people in the future have enough for their needs, not just using it all up ourselves.

Well done.

Now, moving to a sustainable energy model is not an easy task.

There is no simple answer to achieving sustainable energy.

And there is also, as we've just seen by looking at the renewable energy resources, there's no single source that will be able to meet all of our needs all of the time because of the problems that they have with depending on things like sunshine or wind levels.

What this also does is open up a whole raft of questions that we, as a society, need to grapple with, and hopefully answer.

Firstly, how do we weigh the advantages and disadvantages of each of the types of energy resources.

You know, is one of the advantages so, so significant that it outweighs all of the disadvantages, or are all the advantages and disadvantages of equal weight? It also begs the question, who should decide which of those energy resources we should be using, how they should be used, and even where they should be used? And what happens, or what should happen if people in a neighbourhood object to a renewable energy resource being put in their backyard? So if a large wind farm was being built near them, and they objected, should they win or should they just have to put up with it because, overall, the large wind farm will benefit possibly them and certainly many more people beyond and besides.

So there's a great number of questions which are complex, ethical, and social questions that trying to move to a sustainable energy model throws up and doesn't offer any good easy answers to them.

So true or false? Scientists alone can develop sustainable energy.

Well, you should have said that that is false.

But can you explain your answer? So you should have said that some decisions rely on people's opinions rather than the facts that are correct or incorrect.

Now, science can enable decisions to be made on accurate facts and proper understanding, but it doesn't itself give the answers.

Well, if you've got those two points.

Okay, in our last task for today's lesson, what I would like you to do is to consider this scenario.

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

So what I would like you to do is to firstly describe some advantages of building the wind farm.

Then, I would like you to describe some disadvantages of building the wind farm before stating whether you think the wind farm should or should not be built.

And I would like you to explain why.

Now, there's no right answer to that third question, but the justification of your point of view is really important.

So make sure you state a good reason why you think what you think.

So pause the video, and come back to me when you are ready.

Okay, let's see what you wrote.

So firstly, you should have said that the wind farm would provide electricity without harmful emissions, and that once it's constructed, it is pretty inexpensive to operate.

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

So these are all positive reasons for installing the wind turbines there.

To counter that, you should have included the fact that actually providing a wind farm, building it in the first place is really quite expensive.

And during its construction it may disturb the seabed and affect the sea life living there.

Also, many people consider wind farms unattractive, and it might discourage visitors from coming to the resort, and, therefore, it could negatively impact local businesses.

As to whether you think it should or should not be built, there is no right or wrong answer here, but you need to consider which answer, which reasons you think are strongest and, therefore, which one you would favour.

The reality is though other options are likely to be considered and the choice is usually the one that causes the least harm whilst offering the most benefit.

But as we said, that's really quite a difficult thing to judge.

Okay, we've come to the end of our lesson today.

Thank you very much for joining me.

In our lesson today, we've seen how renewable energy resources can be replenished as they are used up, but non-renewable energy resources cannot.

And non-renewable energy resources include fossil fuels, such as coal, oil, and natural gas, and also nuclear fuels, including uranium and plutonium, whereas wind power, solar power, hydroelectricity, tidal power, water waves, biofuels, and geothermal power are all renewable energy resources.

And we've also seen how moving towards sustainable energy means using a range of energy resources in a way that will allow people in the future to have sufficient energy for their needs.

But it is a very complex problem to solve.

So thank you very much for joining me today.

I hope you've enjoyed our lesson, and I hope to see you again soon.

Bye.