Tiki the Penguin’s Guide to Energy

Energy is special. There’s lots of it about and it’s very useful. Why? What makes energy so important? Here’s just a few reasons.

  • it lets me swim fast and catch my fish
  • it gets you out of bed in the morning
  • it means that birds can fly, tigers can roar, wind can blow
  • it makes the sun, the moon and stars shine
  • it makes plants grow — food (= stored plant energy) for animals
  • it makes cars move, factories produce things, light bulbs glow, planes fly and your computer work. I’ll bet you can think of many more!

I’ve made a crossword puzzle about energy. All the answers are in my guide.


Energy is the ability to do work. It’s what you get when you burn fuel

(= stored energy) to move something like a car or kick a ball (= do work). That fuel can be stuff like coal or gas or the hydrogen which powers the sun. What you get is heat and light energy. You can feel the heat from a fire or from the sun on your skin. And sunlight makes our daytime.

Energy can be changed from one form to another but it can't be created or destroyed

People have learned to use stored energy to do useful work for them. By burning coal, you can use the chemical energy stored in the coal to heat up water until it becomes steam which then drives large machines to generate electricity. Electricity is another form of energy and it too can be made to do useful work, like running your washing machine or powering your computer and mp3 player. But electricity doesn’t have to be made by burning coal. It can be made from renewable energy sources like wind and water power. It can also be made by nuclear power

Types of energy

Potential energy is stored in some sort of solid body and has the potential to do work. There are four types:
Chemical: energy stored in things like the food you eat, fossil fuels and explosives
Elastic: energy stored in a stretched elastic band or spring, for example
Gravitational: the energy a body has because it’s near to another large body, like a planet. If a big hole opened up under you, you’d be pulled (fall) down it because of the pull (= energy) of Earth’s gravity
Nuclear: energy stored in the nucleus of atoms. This energy is used in nuclear power stations to generate heat and is called nuclear fission (= splitting apart).  The Sun and all the other stars shine because of the energy released when atoms of hydrogen fuse together. This is called nuclear fusion.

There are many different types of energy but they’re really all variations of one (or some) of these:
Heat: if you touch something hot, it can be very painful as that heat flows into you
Kinetic: this is the energy which a moving body has. If someone kicks a ball hard and it hits you, it hurts because your body has had to suddenly absorb all that energy and stop the ball
Electrical: this is the kinetic energy of moving charges in an electrical circuit. One example is electricity flowing through an old-fashioned light bulb. It makes both heat and light by passing through a resistance (the light bulb’s filament)
Electromagnetic: light and other radiation are all forms of electromagnetic energy

I used a lot of energy writing this! Now what sort of energy

would that be…?

‘Burn’ in this sense doesn’t have to mean burning with flames, like in a car engine or a fire. It can also mean what happens inside your body when your muscles use energy to make you move about. That too is a sort of slow burning of fuel (sugars)and it releases heat. That’s why you get hot when you run about a lot
Hydrogen is a gas. Almost all the sun is made of it and it ‘burns’ in a very special way called nuclear fusion. This is not ‘burning’ the way we usually think of it, like a bonfire. Nuclear fusion can make enormous amounts of heat and light energy from very tiny amounts of hydrogen fuel. It is this same reaction which powers hydrogen bombs.
Your body, for example, can change the stored POTENTIAL energy in the food you’ve eaten into ‘work’ energy, called KINETIC energy. Kinetic energy powers your muscles to make you run or jump.
This is called the First Law of Thermodynamics

Chemical Energy

Energy can be stored in chemical form such as oil, coal, sugar, fat or in batteries. This stored energy is POTENTIAL energy. To get it to do work, you have to burn the oil or coal. You use stored sugar and fat from the food you eat to ‘burn’ and use as KINETIC energy for moving about.

Electricity generators

These machines are called turbo-generators. They are really two machines: one is a turbine, driven at high speed by the powerful, high pressure steam; the spinning turbine drives the generator which ‘does work’ and makes the electricity, the new and useful form of energy which everyone uses.

Renewable energy

You’ve probably heard about renewable energy, often also called ‘sustainable energy’, meaning it’s an alternative to polluting fuels like coal and oil. Renewable energy comes directly (as heat and light) or indirectly (as wind and waves) from the sun. I’ll tell you more about it later in this guide.

Nuclear power

Nuclear power uses the enormous amount of heat produced by splitting atoms of uranium, a very heavy metal which is found in some of the Earth’s rocks. Apart from the heat inside the Earth (which makes volcanoes erupt), it is the only source of energy which has nothing to do with the sun. I’ll tell you more about this later on in this guide.

Nowadays, more and more people are using compact fluorescent bulbs or LEDs for lighting because these are much more efficient and don’t waste energy producing unwanted heat.

What sort of energy?

Well it’s not nuclear, is it? I’m not a nuclear penguin! Could it be kinetic do you you think?

Almost all energy comes from the sun which warms our planet and makes plants grow.

Plants are smart because they can use the sun’s energy not only to make them grow, but also to make roots to store energy. They use this energy – if people don’t eat them first – to make seeds in their second year.

Most plants make seeds, some of which grow into new plants. And animals like you humans eat them – you know, wheat seeds which you make into bread; maize into tortillas mejicanas popcorn or cornflakes and so on. This means you get your energy from eating plants, or by eating other animals like cows which have fed off plants.

I get my energy from eating fish…See this fish?

It ate smaller fish which ate shrimpy things (called krill) …

This is called a food web or food chain

…which feed off tiny planktonic plants or algae from under floating ice.

This is where most humans’ waste products go… down the pan! Our waste products eventually all go back to plants where they start the cycle again, fuelled by energy from the sun.

Si, es la verdad. Yo puedo hablar español
Urine and faeces are the polite names for the liquid and solid wastes that come out of every body, but there are many more, mostly rude!
All this flushing causes another problem. Toilets use a lot of good quality water. Many countries don’t have enough water so flushing toilets are a big problem. There are other types of toilet which use little or no water and also produce good quality compost: food for plants. But most people don’t like them because they are used to flushing and think that any alternative must be smelly and disgusting. While that used to be true, it isn’t any more.
Fixing nitrogen<F/3> Plants need nitrogen (chemical symbol N) to grow well. They also need phosphorus (chemical symbol P; from phosphate rock) and potassium (chemical symbol K). So artificial fertilisers are a mixture of the three: NPK. The nitrogen for the NPK fertilisers comes from the air &mdash: free, you might think &mdash: but there’s a huge energy price to pay for changing it from nitrogen gas into the nitrate needed for plant fertiliser. Some plants &mdash: legumes like clover, peas and beans &mdash: can ‘fix’ their own nitrogen using the sun’s energy so they don’t need artificial nitrates. Organic farmers grow a lot of legumes for most of their nitrogen needs.
Sewage causes obvious smelly pollution while swamping the rivers and seas with far too much nutrient. Nutrient is food for plants but too much of it can kill off almost everything in the water, especially fish and corals. It can also cause microscopic plants called algae to grow into massive blooms which cover everything in often-poisonous slime. This type of pollution has a special name: eutrophication.

Nauru is a small island in the southwest Pacific Ocean. It was once covered in a thick layer of phosphate rock, built up over thousands of years from decayed oceanic microorganisms and bird droppings. This has all been stripped bare by mining because this rock is a valuable fertiliser for farming. The result is a parched bare rock moonscape with no soil so no vegetation, and serious problems for the people who live there.

Fixing nitrogen

Plants need nitrogen (chemical symbol N) to grow well. They also need phosphorus (chemical symbol P; from phosphate rock) and potassium (chemical symbol K). So artificial fertilisers are a mixture of the three: NPK. The nitrogen for the NPK fertilisers comes from the air &mdash: free, you might think &mdash: but there’s a huge energy price to pay for changing it from nitrogen gas into the nitrate needed for plant fertiliser. Some plants &mdash: legumes like clover, peas and beans &mdash: can ‘fix’ their own nitrogen using the sun’s energy so they don’t need artificial nitrates. Organic farmers grow a lot of legumes for most of their nitrogen needs.

What are fuels? How do you get energy from them?

Now this is where humans are different from all other life. You have learned how you can use fuels to make energy to power machines like cars, planes and computers. This way, you don’t have to work so much and you can stay warm without the fat, fur or feathers that other animals have. You get the fuel to make all this extra energy mostly by digging it out of the ground and burning it. This releases ancient energy stores – fossil fuels – made by billions of tiny plants and animals which lived millions of years ago. This stuff has been locked away underground ever since, covered up by younger rocks that got laid down on top.

I’m sure you know what these fuels are:


These fossil fuels all come from underground; inside the Earth’s crust. And that is where they should stay because burning them does a lot of damage to the air we all breathe, the oceans and living things on the land. I’ll say more about that later in this guide.

You can burn any of these fuels, coal, oil or gas, to make electricity in power stations. How?

But electricity is only one form of energy used by people. The biggest guzzlers of energy from burning fossil fuels are

  • keeping homes and offices warm in winter and cool in summer
  • transport: you know… cars, buses, some trains, ships and aircraft

Fuels for heating can be any fossil fuel though people mostly use oil or gas because they’re easier and less dirty.

Machines for transport almost all use the liquid fossil fuel, oil. Why?

But the oil has to be refined to make gasoline, diesel and kerosene. Different types of engine need different types of liquid fuel. Some engines run on gasgas.

Clever plants

Plants are remarkable. They can suck carbon dioxide out of the air and build their bodies out of the carbon. This carbon – along with water – becomes part of their skeletons, holding them up in the air like grass or even giant trees. Plants grab the carbon out of the air using a complex process called photosynthesis. Photosynthesis needs energy to make it happen and this comes from the sun.

Air and swamps

If air (or rather the oxygen in the air) can get at dead plants, they decay (rot). This happens because microbes, which need air, feed on the plant remains and turn their carbon into carbon dioxide. It’s really like slow burning. And as with burning, there’s hardly anything left afterwards. All the carbon the plants took out of the air has gone back into the air. But when plants die and become part of a stinky swamp, the air and microbes can’t get at the dead plant remains. Scientists call the resulting black stinky sludge ‘anoxic’, meaning ‘without oxygen’. This means that the carbon of the dead plants stays put and eventually becomes coal.

king electricity

The fuel is burned to heat water in strong tanks (boilers) to make high-pressure steam. Steam then drives big machines called turbines which, in turn, drive other machines called generators. Result? Electricity which comes to you along wires. Oh, and don’t forget all that pollution which comes out of the chimneys! People do forget because most of it (carbon dioxide, CO2) is invisible. Just imagine: if carbon dioxide was a red (for danger) gas, how differently people might behave.

Oil is very easy to move around and is the most convenient of all the fuels to use in engines. It’s quick and easy to fill a car’s gasoline tank and the fuel has a high energy density (you can drive a long way on a tankful) without being too dangerous to use (though the lighter fuels like gasoline are highly flammable

Gasoline, gas and confusion

In North America, people use the word ‘gas’ to mean ‘gasoline’ which is called ‘petrol’ in other countries. This is the smelly liquid people put in their cars to make them go. ‘Gas’ is also the stuff many people use to cook with or heat their houses. It is a real gas, like air, called methane.

What is diesel fuel?

Diesel fuel, named after the type of engine that burns it, is a more oily sort of fuel than gasoline. Diesel engines are around 30 per cent more efficient than gasoline engines so they use much less fuel.

A fuel similar to diesel which gets burned in aircraft engines and in home heating furnaces. In poor countries, it is much used for cooking.

Gas engines

The gas they use is liquefied petroleum gas (LPG) stored in high-pressure fuel tanks. This gas can be used in modified ordinary engines which are generally less polluting than those that use diesel or gasoline (petrol). But they’re still using fossil fuel.

What you don’t see so easily is the effects of burning all these fossil fuels. You can’t see carbon dioxide and most of you don’t live near huge power station chimneys belching smoke, but no one can escape the noise and stink made by cars, trucks, boats, ships and aeroplanes. Did you know that there are over 500,000,000 cars and trucks in the world, all belching fumes? Then there’s the planes, ships and factories, all gushing smoke and poisonous gases into the air we all breathe.

What happens to this pollution?

What is it?

Why does it affect the climate?

Facts about CO2

Carbon dioxide, chemical formula ‘CO2’ is a colourless heavy gas. It’s what you get when you burn coal, the filthiest fossil fuel. For every ton of coal which gets burned, 1.8 tons of CO2 end up ‘thrown away’ into the atmosphere. Why so much? Because coal burns – or oxidises – in air, nearly a quarter of which is made of oxygen. The oxygen combines with the coal (almost pure carbon) to make the heavy CO2 gas which is the main cause of ‘greenhouse’ warming of the planet.

Why have chimneys?

Chimneys are made very high to pour out the smoke and gas pollution so that it doesn’t poison the neighbourhood. Instead, it becomes someone else’s problem somewhere else. It typically causes ‘acid rain’ and can seriously pollute lakes and rivers far away, especially in the Arctic

Mostly it’s smoke and gases which come from burning fuels to make energy. But it isn’t always obvious.

Some of the polluting gases stink – yuk! That’s obvious!

Some pollution is clouds of black soot particles.

Some pollutants are deadly poisonous and can kill people.

But the main pollution is that colourless heavy gas which just about everyone has heard of: carbon dioxide (often shortened to CO2). This gas has no smell and people use it to put the fizz in fizzy drinks. It is also a 'greenhouse' gas.… and that spells trouble for the planet’s climate. Most CO2 comes from people burning fossil fuels and destroying forests.

For more about pollution, see my pollution guide. For more about greenhouse gases and climate change, take a look at my Hot Earth guide.

What is greenhouse gas?

Some gases in the air act like the panes of glass in a greenhouse. They let the heat of the sun IN but they stop it going OUT. So the greenhouse gets hot. This is happening in the Earth’s atmosphere because people are adding vast amounts of extra greenhouse gases which mostly come from burning fossil fuels.

You’ve probably heard about the ‘greenhouse effect’. If you walk into a greenhouse on a sunny day, it’s very warm inside because the Sun’s heat is trapped by the glass. Carbon dioxide gas pumped into the air by burning fuels has just the same effect: it traps the Sun’s heat energy near the surface of the Earth making the air and oceans warmer. This is what scientists call climate change or global warming. The Earth is warmer than it should be so the seas and oceans take up more space because warmer water expands. The warming is also making icy places like the Arctic and my home, the Antarctic, melt away. Lots of my penguin friends are dying because of this and because of pollution. The melted ice drains into the oceans, making sea levels rise even more.

Warming means that the level of the sea goes up everywhere causing lots of floods. Warming also means more unpleasant weather with more and bigger hurricanes, typhoons, tornadoes and cyclones.. That means lots of people will get killed – or go hungry because their land is flooded, washed away or their crops spoiled. Other places will get hot and dry as people cut down more and more forests.

I don’t want to see these things happening and I don’t suppose you do either. So what can we do? Don’t worry! There are many ways to slow climate change without having to go without energy.

Although the planet, as a whole, is warming up because of the greenhouse effect, it’s not happening at the same rate everywhere. Some places aren’t getting warmer so much as wetter and windier. So the term ‘climate change’ is more useful.

Sea level rise

Floating ice, like that in the Arctic doesn’t affect sea levels when it melts. What does affect the levels are the ice sheets and glaciers which cover most of Greenland and Antarctica. The Greenland ice is melting fast and if it all melts, sea levels everywhere would rise by about 8 metres. That means flooding on a massive scale all around the world.

There is more and more evidence that this is actually happening as storms release more rain and cause terrible flooding.

Cutting the forests

Cutting down forests in tropical parts of the world turns out to be more destructive than you’d think. And much of the destruction is against the laws of the countries where it’s happening. It’s not just that the beautiful giant trees get cut and dragged away: the result is a big mess which is either abandoned or turned into plantations. Either way, the result is that the area that used to be forest gives off lots of CO2, adding to climate change problems where once there were big trees which took CO2 out of the air and stored it. As for all the animals and plants that had their homes in the forest… well, they’re all dead.

Nuclear power – Help at hand?

Radioactivity gets made inside nuclear power plants as the fuel – uranium metal – splits into other elements which give off radiation. So far, no one has worked out a way to safely dispose of the waste this makes, so at present it’s all stored – huge quantities of it. And if the power plant goes wrong (Chernobyl) or is damaged by earthquake and tsunami, terrible disasters can happen.

Facts about Radiation

Radiation is scary because no one can tell it’s there without special detectors. Animals like you and me have senses which means we can see, hear, touch, taste, smell – but we can’t tell if something is radioactive. Waste products from making nuclear bombs and from nuclear power plants are very radioactive indeed. If you happened to fall into a nuclear reactor, you would die almost instantly. Lower radiation levels can also make people die – over a matter of days or, by causing illnesses like cancer, over a period of years. Radiation comes from new elements (uranium fuel is an element; so is carbon and so is oxygen) which get made during nuclear reactions. The radioactive isotopes of these elements, often only exist for a few weeks or years. But some last for hundreds of thousands of years which is why no one really knows what to do about getting rid of them. Radioactive isotopes have what’s called a half-life. Radioactive isotopes with short half-lives quickly disappear by spewing out streams of tiny particles which travel very fast. This is radiation and it’s dangerous to life like you and me. So if you stand near something radioactive, you’re being hit by trillions of tiny ‘bullets’ all the time. You can’t feel it but these ‘bullets’ damage the cells in your body. A lot of damage breaks them and you die. Less damage messes up their genes and causes cancer and kills you slowly. Like I said, nasty stuff.

If nuclear power is so dangerous, how might it help?

Nuclear power stations have been making electric power for over 50 years. People understand their dangers very well so the risk of using them is less than it used to be. A scientist or nuclear engineer would say ‘the technology has matured’. Nuclear stations have several advantages over other ways to make electricity:

they can run at full power for many months at a time

they can make enormous amounts of power from a small amount of fuel. just one station can provide enough power for a city

they do not themselves produce any greenhouse gases and so don’t cause climate change. Nor do they pollute the atmosphere with smoke containing sulphur and nitrogen oxides unlike coal plants, so they don’t cause acid rain

It’s certain that many more nuclear plants will get built because people are used to having electric power at the flip of a switch all the time. ‘Green’ (environmentalist) people have always been against nuclear power and most still are. They want a world powered by renewables like wind and solar energy. The trouble with that is that renewables aren’t always producing power and people today are totally used to having energy available whenever they want it. Relying on renewables would mean you couldn’t be sure the lights would go on when you flipped that switch! So some Greens now accept that nuclear power should be part of the mix of power sources – including renewables – which could produce a steady, reliable ‘background’ of power at all times. There are some who think that if people are going to go for nuclear power in a big way, it could all be made much safer if the reactors could be built underground. Find out why. And now there are special reactors which can not only generate huge amounts of power but use up the dangerous radioactive stuff which is produced in older reactor types, so they need hardly any fuel. But mostly, these are still on the drawing board – only one or two have ever been built.

So why not go nuclear? Why not build loads of new reactors and make green electricity? There are still problems with nuclear which can’t be easily fixed. The biggest of these is the radioactive waste they make while they’re operating. There are ways to deal with this, some short term and some longer term though there is no simple solution to the big issue: nuclear waste is nasty stuff. But there are good reasons to hope that the waste problem can be solved using IFRs.

There are better and safer methods of using nuclear energy. some are just around the corner and some further away. One of the brightest stars is nuclear fusion. This is making energy in the same way that the sun makes it. Instead of splitting atoms to make heat, hydrogen atoms fuse into helium atoms at unbelievably high temperatures such as you find in the middle of the sun: that’s around 50 million degrees. This fusion of atoms gives off really massive amounts of heat and light which is why our sun is hot and bright. Scientists believe that they can mimic the sun in fusion reactors here on Earth but using the technology as an energy source is still many years in the future.

Let’s now look at the energy alternatives, called renewables, so you can decide for yourself which energy source is best.

That means it gives off radiation.

What’s a half-life?

If an isotope of an element – let’s choose iodine as an example – has a half-life of 8 days, this means that if you start with a chunk of the iodine-131 isotope which weighs 100 grams, 8 days later, it will weight exactly half what it did: 50 grams. Sixteen days from the start, it will weigh just 25 grams. And so on. So isotopes with short half-lives don’t stick around long.

One station can typically generate 1 gigawatt of power. One gigawatt is 1,000,000,000 watts; that’s one thousand million watts. Of course, 1 watt is a very small amount of energy but it’s enough to keep a modern TV on standby
Mining and processing nuclear fuel, building the power station and taking it to bits again at the end of its life does create greenhouse gases. So does mining coal and building power stations to burn it. But it’s the burning of the coal which really gives off monstrous amounts of CO2. ‘Burning’ nuclear fuel – whatever it is – does not do this.
Acid rain is caused by burning fossil fuels like gasoline and coal. Burning these fuels creates gases called sulphur dioxide and nitrogen oxides. These dissolve in raindrops to form acids: sulphuric and nitric acid.

Using waste

Waste can be turned back into useful fuel in a very tricky operation called ‘reprocessing’. In this, technicians dissolve the highly radioactive fuel rods in acid and, using clever chemistry, separate out the parts which can be re-used as fuel: unused uranium and plutonium. This is called ‘mixed oxide fuel’ (MOX for short) and can be ‘burned’ in reactors. What remains is a hot very radioactive acid liquid which has to be stored in special tanks. This is probably the nastiest stuff humans have ever made. What do you do with it? One solution is to make it into glass blocks which are much safer to store than acid liquid. Another solution is not to reprocess in the first place and leave the fuel as solid radioactive rods. Some countries choose to reprocess; others choose not to.

Permanent storage

Sooner or later, all these stores of hot radioactive stuff have to be made safe. The best answer anyone has come up with so far is to make the liquid wastes into solids – a process called ‘vitrification’ (which means ‘making into glass’). Then the hot solids get buried or stored deep underground in special ‘repositories’. The idea is to make sure this stuff is kept out of harm’s way for many thousands of years during which time the radioactivity will die away to almost nothing. The difficulty is finding good places to do this.

The most dangerous waste has to be kept away from living things for thousands of years before the radioactivity dies down.

Nuclear: what’s coming?

Most reactors in use today rely on complex emergency cooling systems and people to control the reactor. New designs would shut down and be cooled automatically if anything went wrong. Other types of reactor – called fast breeder reactors – can actually make more fuel than they burn and could be used to literally ‘burn up’ the very nuclear wastes which are so dangerous. Yet others could use thorium (Thorium-232) to make its own fuel – another isotope of uranium (Uranium-233) – in a cycle which results in much less radioactive waste

That’s a sort of joke really. All stars are powered by fusion reactions and are very bright indeed!
Where can you get energy, free and forever? Just look up above you when you’re outside on a sunny day … Yes, the Sun gives our planet far more energy than people make from fossil fuels. Its heat drives the mightiest engine of all: the Earth’s climate. It makes you hot when it shines but it also makes winds, waves and rain. How? And people can use all these things to make electricity or heat energy for homes. And most important, unlike fossil fuels, this sort of energy doesn’t damage the Earth and will last for ever!

Sun power (solar power) can make electricity by using things called photovoltaic cells (often just called PV – easier to say) which fit on the roofs or walls of your houses or apartment blocks. Some special cars can run on PV electricity and there’s even a race across Australia in which the cars run only on solar power

PV panels on a house in the USA

Sun power can heat water in solar panels (like radiators but instead of giving out heat, they grab it from the Sun). This is then stored in a big tank so you can have hot showers and so on. Solar collectors can pick up the sun’s heat even on cloudy days

Solar hot water panels on a hotel roof in Greece

Solar power can also directly heat houses in cold countries – when they’re properly designed to make best use of it. So far, not many are. This is called passive solar energy

This glass conservatory captures the sun’s heat and warms this farmhouse in Wales

Hydroelectric power makes electricity by using the energy from falling water. The water comes from big dams across rivers, and flows down great tubes to drive electricity generators. Most of the world’s biggest rivers are already used for this

The Three Gorges Dam in China is the largest hydro-electric power station in the world

Wind power can drive a turbine with a propeller (like some airplanes have) and make electricity. Wind power is getting really important in some countries. Here’s a cartoon video (like Wallace and Gromit!) about wind turbines which I rather like!

A big wind turbine in Denmark. Can you make out the door at the bottom?

Wave power can also drive generators but this is still a very new idea. Just a few experimental machines are in use today.

Pelamis wave machine in operation off Portugal

Tides – you know, when the sea goes up and down twice a day – can drive generators too. There’s just one example of this in action at a place called La Rance in France. Other parts of the world with big tides could be useful too, but a big dam has to be built to trap the moving seawater

Tidal power plant on the estuary of the Rance River, Bretagne, France

Biogas (methane) for cooking and heating can be made from human sewage and farm animals’ waste. (Phew! Yuk! … but very useful.) It’s made in special tanks called biodigesters. Landfills – that’s where people’s garbage gets dumped – also produce methane gas as the rubbish rots. Usually this is collected and used to make electricity

A working biodigester on a farm in Germany

Biofuels: Because plants and trees soak up CO2 like sponges, making the carbon into wood and putting back oxygen into the air, people can ‘grow’ fuel without adding CO2 pollution to the air. It’s called ‘carbon neutral’. In Brazil, people pioneered growing sugar cane plants to make alcohol which they use to power almost half the country’s cars. In other countries, people plant special trees (like willow) which grow fast and you can cut them down without killing them – so they keep on re-growing. This is called coppicing. You can use the wood for burning to make heat as well as other things.

Other biofuels like ethanol and palm oil seemed like a good idea at first but they’ve turned out to be a bit of a disaster. Why?

Sugar cane, cut and ready for processing

Fuel cells make electricity directly from hydrogen, a very light gas. The cells don’t burn the hydrogen. Instead it reacts with oxygen (in the air) to make electricity. The only ‘waste’ is water. Soon cars will run with fuel cells powering electric motors so they are silent and make no pollution. They can also make power for houses so there’d be no need for big polluting power stations. One way people can make hydrogen is by using sunlight to split water into hydrogen and oxygen gases. Scientists are still searching for a good way to do this.

A hydrogen fuel cell public bus in Australia

Geothermal energy is energy tapped from inside the Earth. It’s the only renewable energy source which has nothing to do with the Sun. Deep down, it’s very hot. Sometimes these hot rocks break through the surface to form volcanoes. By drilling holes down into areas where hot rocks are close to the surface, people can generate electricity and heat buildings. One type of geothermal energy uses geothermal heat pumps to make hot water for home heating. A heat pump is a sort of reversed refrigerator. A different sort of heat pump takes its heat from the air outside a house and warms the air inside. Sounds impossible, doesn’t it, but it works!

Geothermal power plant in Iceland

Sun, wind, waves and rain

The Sun drives our planet’s weather. It does this by heating the air and hot air rises – which is why hot air balloons work. The rising hot air sucks in cooler air to replace it and this is what we call WIND. And the wind, when it blows across the sea, makes WAVES. The rising hot air also forms clouds as it expands and cools again. And clouds make RAIN. But it’s the Sun which drives all of the wind, waves and rain making what people call WEATHER.

Ethanol is a type of alcohol. To make it, people are turning food crops like maize (corn) into fuel instead of food.
Palm oil comes from vast plantations of oil palms in some tropical countries.

Problems with hydrogen

Hydrogen when mixed with air is highly explosive. It is also very difficult to store which is a big problem if it is to be used for powering transport. And producing it needs a lot of electrical energy.

What is ‘carbon neutral’?

When a tree or plant grows, it sucks in carbon dioxide from the air and makes it into other carbon compounds like wood or sugars. If people later then burn these, or make them into biofuels, the same amount of carbon goes back into the air. So this cycle or growth followed by burning is not adding more carbon to the air than was taken out in the first place by the tree. So it’s called ‘carbon neutral’. Fossil fuels like oil and coal add more carbon to the atmosphere every time they are used so they are not carbon neutral.

Oil from the fruits of these palms has long been used in foods but now it is being used on a much larger scale to make a biofuel called biodiesel.

Fair shares

Some people are very greedy and want more than their fair share of everything. So they grab it, leaving little or nothing for anyone else. Many people in rich countries use much more energy than is sensible or fair. Fossil fuels will run out completely quite soon but before they do, the damage to the Earth’s climate will have been done.

What you can do

But wait a moment. That doesn’t mean you’ve all got to grow fur or feathers. You, your friends and families could do lots to make things better:

Get to be energy-aware! Try to save as much as you can by not driving around, flying and having the heating or air conditioning turned up so high. People can also save a lot by making clever buildings which can make their own energy and don’t waste the energy they do use. Insulation isn’t very exciting but it’s the quickest, cheapest and best way to save energy in homes, schools and offices. Most buildings don’t have proper insulation but there are simple ways to add it which not only means warmer (or cooler if you live in a hot place) buildings. Because much less energy is needed, you save lots of money: energy is getting very expensive to buy

Use your own energy to do things – cycling, walking, running, cooking. If you’re cold, wear more clothes! It’s a no-brainer, don’t you think? ;)

find out more about renewable energy and pester parents and friends to get involved in using these or in trying to get something going where you live. And since energy use and climate change are connected, take a look at my Twelve Really Important Things you can do to help stop global warming

I’ve made a crossword puzzle about energy. All the answers are in my guide. Can you get it all correct?
I’m off to catch a fish for my dinner. I’ll be walking (okay, waddling!) and then swimming to do that, not jumping in a car. What will you be doing? I hope that whatever you do, you’ll think carefully about it first.


Because how you choose to use energy affects all life on Earth so please think before you use energy and think about what sort of energy you use. Anything which uses fossil fuel is bad news for the planet.

Want to find out more? Visit my Energy links page by clicking here.


If you’ve found my Energy Guide useful, please would you be kind enough to make a donation to help run my website. I know you kids don’t have credit cards or anything but perhaps you could persuade either your parents or your school to make a donation. It’s so easy and you can do it here.

How long can fossil fuels last?

Coal is–unfortunately because it is the most polluting fuel–plentiful. Oil production may have peaked but nobody knows for sure. Natural gas is abundant and ‘fracking’ (I’ve written a guide about this) allows energy companies to get at much more gas from shales buried deep underground. Gas is the least polluting fuel because it contains 4 hydrogen atoms for every carbon. This means that when it burns, it produces less CO2 per unit of heat than oil or coal.


‘Retrofitting’ means adding insulation to an older building which has none. It’s usually easy to add thick loft insulation, but if a house has solid walls, these have to be lined (either inside or outside). The ideal is to build new houses with the very best insulation but there are millions of older houses which can be retrofitted to make them much more energy-efficient.

How to stay warm

If you’re cold, instead of turning up the heating, wear warm clothes and do something vigorous like running. Using your muscles generates heat and helps keep you slim and fit too!

There are loads of places to visit so I’ve just selected a few which I like the best. And please avoid disappointment and don’t send me more links, no matter how useful you think they are. Lots of people do but I simply don’t have time to deal with them. Sorry!