Renewable Sources of Energy
Out of energy? You aren't the only one!
You know how sometimes you feel like going outside to play with your friends or ride your bike, but you just don’t have the energy?
Think how planet Earth must feel.
For thousands of years, people have been using the Earth’s resources for energy. People all over the world have used coal, oil, and natural gas for heating and cooking. These are called fossil fuels, because over millions of years the dead bodies or fossils of plants, animals, and even microscopic creatures were slowly converted into these substances. If you want to know more about how these fossil fuels were created, read What Is Natural Gas?
But the amount of fossil fuels in the ground is limited. We can’t wait another few million years for more to be formed, so when it’s all used up, it’s finished. And as people all over the world use more energy for electricity, vehicles, heating, and industry, etc., a lot of our fuel reserves are going to be used up.
It’s also true that when fossil fuels are burned, they produce greenhouse gases, which cause a rise in global temperature. This increased heat, called global warming, makes the dry season drier, the rainy season wetter and winters harsher. A lot of animal habitats are also harmed. People therefore need to reduce their use of these fuels, to give our planet a chance to heal.
But we still need energy. Who wants to live without electrical power, or cars, computers and video games? The answer isn’t to stop using energy, but to start using energy in a smarter way.
And how do we do this?
Renewable resources are forms of energy that can be used over and over. They can’t be used up like fossil fuels can. So they will always be around, and they will always be available. Let’s look at a few of them.
If you really think about it, the heat from the sun is the source of all energy. You can even consider it the source of all life, because without the sun, nothing on this planet could survive.
At its centre, the sun is about 15 million degrees Celsius, and its surface is about 2 million degrees Celsius. That’s a lot of energy!
What if we could harness some of that energy?
Well, we can. Solar energy is energy from the sun. The simplest way to use it is to allow its rays to heat things up, like a swimming pool on a hot day. But you can also capture the heat and use it to heat water in your home, or even turn it into electricity. For this, people use solar panels, which are like huge window panes made of silicon (which is made from sand) and fine wires.
As the panels heat up, electrons in the silicon vibrate and flow through the wires. And what does that create? Electricity!
You can even connect the solar panels to huge rechargeable batteries, which store energy to be used later. That way, on cloudy days or at night when the sun isn’t visible, you’ll still have energy at your fingertips.
What makes a kite rise up to the sky? What makes your hair blow into your face when you’re outside? What makes a windmill spin?
That’s right! Wind!
Wind is a great source of energy because in many places it’s always blowing…and you don’t need to pay for it.
In some countries, people have created wind farms, large areas of land covered with wind turbines or windmills. They capture the wind when it blows and, depending on their design, can generate electricity (turbines) or mechanical energy (windmills).
Mechanical energy can be used to power machines such as mills for threshing flour. Electrical energy can be used for…well…just about anything.
And, like solar energy, it’s good for the environment because there are no greenhouse gases involved!
Quick…what do you think of when you hear “rotten vegetables”? What about “cow manure” or “decomposing grass”? Ick, ick, and ick, right?
Well, would you believe that rotting organic matter is one of the best sources of renewable energy?
One of these fuels is ethanol, a form of alcohol that comes from the sugars in decomposing grains, such as corn, rice, sugar cane and potato skins. Small amounts of ethanol can be mixed with gasoline to create a clean-burning fuel. There are even some special cars that can use very high proportions of ethanol to gasoline, which makes them very environment friendly.
Then there is biodiesel, a fuel that is made from vegetable oils and animal fats. In some countries, oil that was used for frying food is collected and converted into biodiesel. It can be mixed with diesel from petroleum and used as a vehicular fuel.
If you really think about it, cow manure isn’t as gross as it seems. It’s really just processed grass, with lots of fibre and proteins left in it. In places where there are huge numbers of animals on dairy and meat farms, the manure is collected and sent to special plants, where the fibre and proteins in the manure is separated. The fibre is converted to ethanol, and the protein is used as a fertiliser. It’s a smart, environment friendly way to recycle a very natural product.
And if you’re still grossed out, think about this: using this method, a farmer can make more money from his cows’ manure than their milk!
In some poor countries, dried pats of manure are highly valued for their high energy content. They are burned in cooking fires and ovens just like coal or wood. This isn’t such a good thing, though, as burning manure is very high in pollutants.
We live on an island, so there is water all around us. Imagine what we could do if we could capture the power of moving water and turn it into energy!
We can, and it’s called hydroelectric power. It’s one of the cleanest and cheapest sources of energy. Large bodies of water are dammed up, forming a reservoir or lake. The water is allowed to flow through a narrow space, so that, as it falls, it exerts tremendous force onto the blades of a giant turbine below.
Remember what it feels like to be knocked over by a wave at Maracas? That’s because the energy stored in the wave is able to push you down. Imagine how much energy is stored in an entire dam! You certainly wouldn’t want to fall into THAT!
As the water falls onto the turbines, the blades spin. The turbine is connected to a generator, which converts the water’s energy into electricity. And don’t worry; the water isn’t wasted. It’s sent right back to the dam, where it’s used again.
Hydroelectric power is so cheap and easy to use that in some countries entire cities are powered by it. And the best part is, we always have water. It’s a truly renewable resource.
What can you do to help?
Now that you understand why it’s so important to find cheap, plentiful, reliable sources of renewable energy in order to save the planet from global warming, what can you do to help?
You probably can’t build your own solar panel or your own dam, but remember, you still have power to help the Earth.
Why don’t you think about an idea that will encourage people to conserve energy? Write an essay, draw a picture, think of a new way to reduce, reuse and recycle everyday materials.
Then send it to us, and we’d be happy to feature it on NGC’s website. You never know: your idea may just be the one to start a new green revolution!