Lesson video

Hello, my name is Mr. March, and I'm here today to teach you all about the classification of energy, non-renewable, renewable, and recyclable.

So grab everything you need for today's lesson and let's get going.

By the end of today's lesson, you'll be able to classify sources of energy into renewable, non-renewable, and recyclable energy.

We have three key terms in today's lesson.

Those are non-renewable energy, renewable energy, and recyclable energy.

Non-renewable energy refers to a natural source of energy that will run out because it cannot be reproduced, such as coal, oil, and gas.

Renewable energy refers to a natural source of energy that will never run out, such as flows of wind, water, and solar energy.

Finally, recyclable energy refers to a source of energy that can be reused, and so will last into the future, such as biofuels and nuclear energy.

We have three learning cycles for today's lesson.

We're gonna start with learning cycle one, which is all about non-renewable energy.

Now, what do you think then uses up the most energy in an average household? Is it heating? Is it hot water? Is it cooking? Is it washing and drying and clothes? Is it lighting? Is it TV and games consoles? Is it phone charging? Now, you may like to pause the video here whilst you consider your own answer to that question, or better still perhaps, even have a discussion with someone near you.

So what did you think? Well, the correct answer is actually heating.

Heating accounts about 60% of our energy usage.

Now, most of our electricity is actually generated through a rather simple process.

It starts by taking a source of energy, which then converts water into steam, and this steam then turns a turbine, which drives a generator and which produces and creates electricity which then supplies our energy grid and provides electricity into our homes.

The most common way of generating electricity used to be by burning fossil fuels, such as coal, oil, or natural gas.

And currently, around 33% of UK electricity is still generated in this old fashioned or traditional way of generating electricity and energy.

And around only 1% comes from burning coal.

But other sources of energy can be used to generate electricity too.

For example, biofuels, by which I mean things such as ethanol or biodiesel, essentially a fuel which is created from the waste product, or perhaps animal waste, or even agricultural waste such as maize, can be burned instead of fossil fuels.

Now, at the moment, around 5% of UK electricity is generated by burning such biofuels.

So time now for a learning check, and it says which of the following are fossil fuels? Now you've got three options on the screen in front of you.

What you need to do then is pause the video here whilst you select all answers that you think are correct.

And the two correct answers we were looking for were coal and natural gas.

Really well done if you're able to select those two correct answers.

Our next learning check says, currently, what percentage of UK electricity is generated by burning fossil fuel? Now what you need to do once again is pause the video here whilst you read through those four options and select what you think is the correct answer.

And the correct answer was c, around a third.

Around 33% of UK electricity is currently created by burning fossil fuels.

Really, really well done if you also managed to select c as the correct answer.

Fossil fuels then, such as coal, oil, and gas, are non-renewable resources.

They release a huge amount of energy when burned, but they take thousands of years to form.

This means that they just can't be replaced or renewed quickly enough to actually meet our needs.

As Jun says, "Burning fossil fuels also releases a lot of carbon dioxide, doesn't it?" And as Andeep says, "I guess non-renewable means these are not sustainable too?" And both Jun and Andeep are absolutely correct in their assertions.

Burning fossil fuels are environmentally very, very damaging by releasing a huge quantity of carbon dioxide into our atmosphere.

And as we perhaps know, this is leading to things such as global warming and climate change.

Meanwhile, Andeep is also correct.

The fact that they're non-renewable means that they're not sustainable, since they are very, very, they take a long time to be replaced and renewed, and so it's not sustainable to use these types of fossil fuels at the rate that we currently are.

So a quick learning check.

It says, which of the following are problems with non-renewable energy sources? You have four options on the screen.

What I need you to do then is pause the video here whilst you read through those four options and you select all answers that you think are correct.

And the correct answers are b, burning them is a major source of carbon emissions, and d, they do not renew fast enough to meet human needs, and therefore they are not sustainable.

So really well done if you too were able to select b and d as the correct answers.

We're on now to our two practise tasks for our first learning cycle.

And the first one says, what percentage of UK electricity generation in 2023 came from non-renewable energy? So there you can see you have the donut graph in front of you, and you need to try to find out how much electricity generation in 2023 came from non-renewable energy sources.

The second practise task says compare the UK's use of non-renewable energy in 2023 with that of Indonesia in the same year.

So what you need to do right now then is pause the video whilst you attempt these two practise tasks.

Best of luck.

And now for some feedback.

So you were asked to try to identify what percentage of UK electricity generation in 2023 came from non-renewable energy sources.

So first of all, we need to look at the graph in front of you.

And we need to identify the non-renewable energy types.

And those are coal, gas, and oil.

And when we add up their percentages, it totals 40.

1%.

The second question said then to compare the UK's use of non-renewable energy in 2023 with that of Indonesia in the same year.

You may have made points such as the following.

The fact that in the UK, 40.

1% of electricity is from non-renewable energy.

For Indonesia, it is 81.

5%, double the UK.

As well as this, while coal is only 1.

4% in the UK, in Indonesia, it's actually the biggest energy source for electricity generation, at 62.

1%.

Now, really well done if you too were able to include anything like that in your own answer.

We're on now to our second learning cycle, which is all about renewable energy types.

Now renewable energy comes from sources that don't run out or are quickly renewed or replaced.

And they really derive from three main sources, the sun, the wind, and water.

And we've got some good examples on the screen in front of you.

So the first of course are solar panels.

And these are panels which absorb energy, solar energy, from the sun.

And the next then is derived from wind.

We can see wind turbines.

They're generating electricity via turning a turbine.

And finally then we have water flow.

And we can see the example of a hydroelectric dam, which is creating hydroelectric power, once again via turning a turbine.

And we also know this as HEP, hydroelectric power, or simply as hydro.

Some sources of information, like our World In Data, have a category called other sources of renewables.

The main sources of renewable energy are solar, wind, and hydroelectric power, or HEP.

And other sources of renewable energy can also include geothermal.

This uses heat from within the Earth to heat water to power turbines.

We also have tidal power, which uses the rise and fall of the sea to turn turbines and generate electricity, while concentrated solar power, or CSP, uses mirrors to focus sunlight on a central receiver, often a tall tower, like in the picture that you can see, which shows a CSP plant in Spain.

The sunlight heats up the fluid, usually molten salt, to very high temperatures, and then that heat is used to boil water to create steam, which then turns turbines to generate electricity.

Molten salt stays hot for a long time, and so CSP can effectively store power even when the sun is not shining, for example at night.

Time once again for a learning check, and it says the three main sources of renewable energy are? Now you have four options on the screen in front of you.

What you need to do then is pause the video, read through the options, and select what you think is the correct answer.

And the correct answer is d, solar, wind, and water flow.

Now you may have said b, geothermal, tidal flow, and CSP.

And whilst you would be absolutely correct to identify these as renewable energy types, we were looking for the main sources of renewable energy, which is d, solar, wind, and water flow.

So really, really well done if you're able to select d as the correct answer.

Let's take a little bit of time now to try to understand how renewable sources actually generate electricity.

And it comes back to this idea that a turbine needs to turn in order to generate electricity.

Let's start with wind power.

So the flow of wind turns the wind turbine blades, as I'm sure we've seen before.

This rotates a shaft in the wind turbine generator, which generates electricity.

The electricity then goes to a transformer to increase the voltage, usually at the wind farm site.

The electricity can then flow through power cables into the national grid.

And transformers step down the voltage so that it's actually safe for usage.

Now Izzy is absolutely correct when she says, or ask the question at least, "So, no wind means no electricity?" And she's absolutely correct.

And this is one of the weaknesses of using wind power.

How then is electricity generated via water or through hydroelectric power? A dam stores water at a high level.

Water is slowly released and flows downhill through pipes.

The flow of water actually turns the turbines which are connected to generators which generates electricity.

A transformer once again steps up the electricity to a higher voltage for transport to the national grid.

Transformers then step down the voltage so it's now safe for usage.

Now Izzy asked a really, really good question.

She says, "Water can be released whenever power is needed?" And to a certain extent, she's absolutely correct.

By holding water behind a dam and slowly releasing it, it creates a consistent flow of electricity.

Furthermore, should there need to be more power created, then more water can be released, and thereby creating an increase or a spike in electrical production.

But this then does come at the long-term cost because it may lead to a drop or a decrease in the total volume of water being held behind the dam, and thereby lead to potential shortages of electricity in the future.

But, generally, overall, it does actually create a very consistent flow of electricity.

So a quick learning check.

It says true or false.

HEP is more reliable as a source of renewable energy than wind.

What you need to do then is pause the video here whilst you decide your answer.

And the correct answer is true.

Now once again, I'd like you to pause the video whilst you consider as to why the statement then is true.

And the reason it's true is because while wind turbines can only generate electricity when the wind is actually blowing, but because HEP stores water behind the dam, water can be released to flow downhill and generate electricity whenever it is actually needed.

Really, really well done if you're able to identify those two correct answers.

So how then do solar panels actually create or generate electricity? Well, photovoltaic, which are PV cells in the panel, actually absorb photons from sunlight.

The photons dislodge electrons from the silicone in the PV cells, which creates electricity.

An inverter changes the electricity to alternating current, or AC, which is what we use in homes.

Now, once again, Izzy makes a very pertinent point.

She says, "Solar panels only produce electricity when the sun shines?" And although Izzy is right about photovoltaic solar panels only producing electricity when the sun shines, some solar farms actually have battery storage.

So the power produced in the daytime can be stored and used at night.

And as we know, concentrated solar power can also be stored for a while as heat.

How then do we get this electricity from A to point B? How do we get it from those places where the electricity is generated to our homes? Well, the best places for wind farms and HEP are often far from big cities, so they have a huge distance to travel for that electricity to arrive at our homes.

Electricity then can be transported long distance through power cables, as you can see in the image on the screen in front of you.

However, resistance means energy is lost as heat.

And therefore we need to increase the voltage to reduce that amount of resistance.

So the higher voltage means less energy is actually lost during transportation.

Time once again for a learning check.

And it says true or false.

All renewable energy is generated in the same sort of way, turning a turbine to produce electricity.

So I'd like you to pause the video here whilst you carefully consider that statement and then decide on your answer.

And the correct answer is false.

Now what you need to do once again is pause the video whilst you consider as to how or why that statement then is false.

And the reason it's false then is because photovoltaic solar panels convert sunlight into electricity without using a turbine and a generator.

Silicon in the panels releases a flow of electrons which is captured as electricity, direct current, in the panels.

So really, really well done if you were able to identify and recall that piece of information to answer that question.

So we're on now to our two practise tasks for the second learning cycle.

And the first one says, what percentage of all the UK's electricity from renewable energy in 2023 was provided by wind? I need you to also show your calculations.

The second question says describe two trends in the UK electricity generation shown in this graph.

And I would like you to try to use figures from the graph to support your answer.

So what you need to do now then is pause the video whilst you attempt these two practise tasks.

Best of luck.

For the feedback for the first question then, you needed to start by identifying all the different renewable energy types shown in that graph.

And those are wind plus solar plus hydro.

And when you total up all their different percentage contributions, you come out with 34.

2%.

But we are looking specifically at wind.

Now wind accounts for 28.

3%.

So what we can do then is that we can take that 28.

3% and divide it by the total contribution of all the different renewable energy types, which is 34.

2, and we come out with 0.

827.

We can then round it up to 0.

83, times it by 100 to give us our percentage, and that comes out with 83%.

The second practise question then.

Your answer may have included the following.

One trend is a decline in the use of coal to generate electricity.

From 64.

5% in 1990, coal was used to generate just 1.

4% of the UK's electricity in 2023, a decline of 63.

1%.

The answer continues.

A second trend is the rise of wind, which was used to produce 20% of the UK's electricity in 2023, up from 0% in 1990.

2016 was the year when wind overtook coal in terms of percentage share.

Now really well done if you're able to include or identify any of those patterns which I've just mentioned.

We're on now to our third and final learning cycle, and this is all about recyclable energy.

Recyclable energy comes from sources that can be reused, replaced, or recovered in some way.

Now nuclear power is often defined as recyclable energy because the fuel used to create nuclear power can be processed to recycle its uranium and plutonium.

Meanwhile, biofuel, something we looked at earlier in the lesson, is also recyclable energy because crops, like maize, that are grown to process into biofuels can actually be quickly and easily regrown.

Other methods of recycling energy include the following.

Perhaps combustion, burning household and business waste to actually generate electricity.

Gasification, decomposing waste to produce gas, which is then burned once again to generate electricity.

Heat recovery, capturing heat that would otherwise have been wasted, for example, from industrial processes, and using it to once again generate electricity.

Time now for a learning check, and it says true or false.

Recyclable energy is the same as renewable energy.

So what you need to do then is pause the video here whilst you read back through that statement and then select your answer.

And the correct answer is false.

Now, once again, I'd like you to pause the video whilst you consider why this statement is false.

And the reason it's false is because renewable energy comes from natural processes that are constantly renewed, so they never actually run out.

Recyclable energy comes from sources that are often finite, as in they can run out, but which can easily be reprocessed, or reused, or recovered to extend their use in generating energy.

Really well done if you were able to identify those two correct answers.

What makes nuclear energy recyclable then? Well, the fission of uranium fuel creates a huge amount of heat.

This heat is used to create steam to once again turn turbines.

This generates electricity within a generator.

And the fuel becomes depleted over time and highly radioactive, which is of course very hazardous.

The fuel though can be reprocessed and used again to generate energy.

So as Aisha says here, it's recyclable energy because the fuel can be recycled.

And she's 100% correct.

That uranium fuel can be recycled and reused once again to generate electricity.

Not all countries do actually reprocess this depleted nuclear fuel, and once such country is the United States of America.

The USA stopped recycling its nuclear waste in 1977, and we have to ask the question why.

Well, one reason is all to do with nuclear threat or nuclear proliferation, because reprocessing waste actually separates plutonium from the fuel, and plutonium is what is used in nuclear bombs.

So the USA wants to try to avoid this potential problem, which is of course very hazardous and dangerous in terms of nuclear proliferation.

The second reason is cost.

Uranium is not expensive, particularly in the USA where much uranium can actually be mined very cheaply, while reprocessing nuclear waste is comparatively very expensive.

And third and finally then, it's all to do with space.

The USA is a very large country, with large areas that are sparsely populated, meaning that it has a lot of space to actually store this nuclear waste.

So a learning check.

True or false, energy from nuclear power stations is always recyclable energy.

So please pause the video here whilst you decide whether this is true or false.

And the correct answer is false.

Now, once again, I'd like you to pause the video whilst you consider as to why this statement then is false.

And the reason it's false is because nuclear energy can be recyclable energy, because nuclear fuel can be reprocessed and used again.

However, some countries, such as the USA, do not currently recycle nuclear fuel but instead choose to store the highly radioactive waste in secure places.

Really well done if you're able to identify those two correct answers.

Let's now try to explore what biofuels are and how they're actually used and processed.

So biofuels are fuels made from biomass, which essentially just means living things.

And if you look at the table in front of you, we can try to identify different types of fuels and some different examples within them.

So we've got solid fuel, liquid fuel, and gas fuel.

Let's look at solid fuel first.

So some examples then are wood pellets, as well as crop waste.

How is it produced? Well, most wood pellets are made of compressed sawdust, and it can be used to generate power, as well as heating.

What about liquid fuel then? Well, bioethanol, as well as biodiesel, are very famous examples.

Bioethanol is alcohol made from fermenting crops like maize or sugarcane, whilst biodiesel is made from plant and animal fats.

And in terms of its use, well, transportation, as an alternative to petrol or diesel.

And finally, what about gas? One famous example is biogas.

Its production then is via organic material.

Organic material is digested by microorganisms in anaerobic conditions, which essentially just means an environment lacking oxygen, no oxygen.

And finally then, it is used to generate power, as well as heating.

So time now for a learning check, and it says, which of the following then is an example of a biofuel? You have four options on the screen in front of you.

What you need to do then is pause the video here whilst you select the correct answer.

And the correct answer was d, bioethanol, an example of a liquid biofuel.

Really well done if you were able to select that correct answer.

Although biofuels release carbon dioxide, CO2, when they're burned, they are still seen as being carbon neutral.

Why do you think that is? You may like to pause the video here whilst you think of your own answer to that question.

Well, some students have also been considering that question too.

We have Izzy.

Izzy says, "Is it because they don't release very much CO2?" Laura says, "Is it because they absorb CO2 as they grow?" And Andeep says, "Is it because we can recycle their CO2 somehow?" Well, these are all good suggestions, but without doubt Laura is the correct answer.

The amount of CO2 that biofuels release when burned is the same that they absorbed as they grew, which overall means it is neutral.

Now, Andeep was on the right line, but it isn't humans that recycle the CO2 but plants as part of the natural carbon cycle.

So therefore Laura is one who has got the best answer here.

There are undoubted problems with actually using biofuels, for example, if you use arable land to grow biofuel crops and you actually have less land to grow food crops on.

And this could lead to things such as higher food prices, as well as food shortages.

A second problem is that biofuel crops take a lot of water to grow.

They are linked to deforestation, which refers to forest being cleared to create farmland, as well as biodiversity loss.

Even if biofuels are carbon neutral, they can still have major environmental impact.

So a quick learning check.

It says to complete the gaps in this paragraph to show your understanding of recyclable energy.

So what you need to do now then is pause the video whilst you read through that paragraph and do your best to fill in those three gaps that you can see.

So what did you get? Let's have a look at the answers together.

So it says organic material turns into fossil fuels over thousands of years.

Biofuels are also made from organic material, but they are recyclable because it only takes a few years to regrow the organic material used to create them.

Really well done if you're able to fill in those three gaps.

We're on now to our practise tasks for our final learning cycle.

And the first one says, in 2023, recyclable energy sources contributed around a quarter of all of the UK's electricity generation.

Now it says, is that statement true or false? And explain how you know.

The second one says to study the two images in front of you.

Explain why the energy each creates can be classified as recyclable energy.

So you have a nuclear power station on the left and a biodigester, or biogas, on the right.

The third and final question says once again to study those two images and to suggest one disadvantage of each method of generating energy.

So what I'd like you to do then right now is pause the video whilst you attempt these three practise tasks.

Best of luck.

And now for some feedback.

And the first question said, in 2023, recyclable energy sources contributed a quarter of all the UK's electricity generation.

And you needed to decide whether it is true or false.

Well, first of all, it is true.

Now you need to explain how you actually know this.

And your answer could have looked something like this.

The fact that nuclear and biofuels are recyclable energy, and together they make up 25.

7%, and therefore around a quarter of all of the UK's electricity generation.

The second question said explain why the energy each creates can be classified as recyclable energy.

Now your answer may make points similar to some of these.

A nuclear power station uses uranium fuel.

This fuel can be recycled and used again to generate electricity.

Because it can be recycled, it is also classified as recyclable energy.

A biodigester creates biogas by using microorganisms to digest organic material.

Organic material only takes a very short time to be replaced.

And this quick replacement of the organic material fuel is why it is classified as recyclable energy.

The third and final question said to suggest one disadvantage of each method of generating energy.

Now your answer may have included something like this.

One disadvantage of recycling the depleted fuel used for nuclear power is that this nuclear waste is very radioactive, and that makes it very hazardous for humans.

One disadvantage of growing crops to turn into biofuels like biogas is that it takes up land that might be needed to grow food crops, which could lead to higher food prices or even food shortages.

So really well done if you're able to include anything like that in your own answers.

We're on now to our learning summary and what do we need to know from today's lesson.

Well, energy can be classified into non-renewable energy, which refers to finite supplies, meaning that they can run out, such as fossil fuels such as coal, oil, and gas.

They can also be classified into renewable energy, which is energy which can be replaced again and again and again.

They are infinite.

Now, examples include flows of solar, wind, and hydroelectric power.

These are energy types which will never run out.

And finally, recyclable energy, for example, nuclear, biofuels, sources that can be reused, recovered, or easily replaced.

Really, really well done during today's lesson.

It was a pleasure teaching you.

And I will see you again on the next lesson.

Goodbye.