Objectives:

• To understand that a renewable energy resource is one that is being (or can be) replenished as it is used.

Non-Renewable Resources

Some of the energy resources stated on the previous page are non-renewable, this means that as they are used they do not replenish. Coal, oil and gas are known as fossil fuels and these take millions of years to form, there are only so many deposits of fossil fuels on Earth and we are very quickly using them up. They began to be used as an effective fuel resource at the start of the industrial revolution and mainly in the 19th century. In 2018 we are now struggling to find any more fossil fuels on Earth, so in under 200 years we have used up most of this energy resource, yet they took millions of years to form!

Nuclear fuel (material used for fission), is also non-renewable as the atoms required for this nuclear process were actually created in something known as a supernova (where a very large star explodes! – you will learn about this in the space topic if you study triple science). As we use these atoms up, there is no way of replacing them (unless another supernova happens nearby and sends lots to Earth – but this would be apocalyptic). As a result, nuclear fuels such a Uranium are also non-renewable, however we only use small amounts of this in our nuclear power stations and so it is predicted we will have enough of this to fuel out power stations for about 50,000 years!

Renewable Resources

Other energy resources are known as renewable, these are the types that are replenished at a similar rate to us using them up. Bio-fuels for created from very recently deceased living things including both plants and animals. Take a tree for example, if it is one which takes just a couple of years to get to full growth then it can be used as fuel and will only take a short time to replace. Although it is not immediately renewable, if we only use bio-fuels on a very small scale they would be a renewable resource.
A better example of a renewable energy resource would be wind, water or solar power. We will always have the sun heating up our planet (for approximately 5 billion years anyway), this heat creates convection currents in the air (wind) which contributes to water waves. The light energy can also be used to get solar panels working too. As we use this power, it is immediately replaceable.

Below shows the previous list but stating whether they are renewable or not;

• Thermal power stations: non-renewable
• Using bio-fuels: renewable
• Using nuclear fuels: non-renewable
• Wind turbines: renewable
• Hydro-electric power stations: renewable
• Geothermal power stations: renewable
• Harnessing the power from the tides: renewable
• Harnessing water waves energy: renewable
• Using solar energy: renewable

Unfortunately, the most reliable options for harnessing consistent amount fo power has proven to be those that are non-renewable. We burn fossil fuels in thermal power stations to heat water to turn it too steam – but we control how much and the rate at which these fuels are burned. We cannot control how much wind there is on any particular day therefore wind in unreliable!