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Year 7 & 8 TOC

Obtaining Energy

Non-renewable resources for energy

LO: Comparing renewable and non-renewable energy sources, including how they are used in a range of situations. 

We’ve spoken a lot about non-renewable resources and how they can take thousands if not millions of year to form! But these resources make up the majority of ways we produce energy. 

WHAT WILL YOU LEARN?

  1. What are fossil fuels?
  2. Why are they non-renewable?
  3. How is coal, crude oil and gas formed?
  4. How can we use non-renewable resources to generate power?

Fossil fuels

Dinosaur fossils aren’t used to make fossil fuels, in fact animals which lived millions of years before the dinosaurs are used in fossil fuels. They are formed for animals and plants which lived over 100 million years ago. These fossils where alive in the Carboniferous period.

The process of slowly compressing and heating the dead matter into coal, oil and gas takes millions of years to occur. So while, eventually, they will replenish, they won’t replenish quicker than we use them.

Pros
  • At the moment, fossil fuels are relatively cheap and easy to obtain.
  • Much of our infrastructure is designed to run using fossil fuels.
Cons
  • Fossil fuels are non-renewable energy resources. Their supply is limited and they will eventually run out.
  • Coal and oil release sulphur dioxide gas when they burn, which causes breathing problems and contributes to acid rain.
  • When they are burnt they release carbon dioxide, which adds to the greenhouse effect and increases global warming. 

Coal

Coal is formed from dead trees, ferns and other plants (over 300 million years in the Carboniferous period), which grew in tropical swamps.

When the trees and plants died they fell into the swamp. As they sat deep underwater they could not completely rot, due to the lack of oxygen. They eventually built up to form a layer of peat. As time passes, the layer of peat become more and more, and eventually rock formed on top of them. Over time, the weight and pressure of the rocks on top combined with the heat from the earth gradually changed the peat into coal. 

Depending on whether the plants sat in water with large amounts of sulphur, or fresh water with low levels of sulphur, determines how much sulphur they release when they are burnt.

Coal is mined in open cut mines (if it’s close to the surface) or in underground mines.

Depending on the coal we burn, we can release large amounts of sulphur and carbon dioxide into their air as an air pollutant. This can contribute to acid rain and poor air quality. Burning coal also produces the largest amount of CO2 emissions of all fossil fuels.

The Yallourn Power Station is located in Latrobe valley and is a complex of 6 brown coal fuelled thermal power stations. Most of Victoria’s power is generated by power stations in the Latrobe valley.  Black coal resources are found near Sydney and central and eastern Queensland. To generate electricity we burn the fossil fuels and heat up water. We then use the steam produced to turn a turbine connected to a generator. 

Crude oil & gas

Crude oil and natural gas were created from organisms that lived in water and buried under the ocean or river sediment. Ancient rivers which were present millions of years ago have now dried up. Heat, pressure and bacteria combined and cooked the organic material under the earth. Closer to the surface Oil forms, but the deeper we go the hotter it gets and natural gas is formed. 

Over time the gas and oil rose, seeping through the earths crust, until it was eventually stopped by a thick layer called ‘Caprocks’.  In order to get crude oil or gas we need to drill deep into the ground and pump the liquid or gas out. Select the images below.

We can use crude oil to produce things like plastics, artificial food flavourings, heating oil, petrol, diesel, jet fuel, and propane. We can use natural gas to heat homes, gas ovens, grills and even your Bunsen burner.

Fossil fuel reserves

Select the ‘i’ icons to learn more about the fossil fuel reserves available in the world.  

Uranium and Nuclear power

In nuclear fission we start a chain reaction of splitting an atom. Uranium will continue to split until it becomes a stable element. Until that point it is giving out energy and heat. The heat energy given off is what we use to heat water. This creates steam which is pressurised to turn a turbine and generate electricity.

Nuclear reactors produce toxic waist. Although the waste isn’t emitted to the atmosphere it is still dangerous. The waist needs to be stored for hundreds or thousands of years before it becomes harmless. This means the waste has to be stored in remote area, far away from civilisation.

Pros
  • Unlike fossil fuels, nuclear fuels do not produce carbon dioxide or sulphur dioxide.
  • 1 kg of nuclear fuel produces millions of times more energy than 1 kg of coal.
Cons
  • It is a non-renewable resources.
  • If there is an accident, large amounts of radioactive material could be released into the environment.
  • Nuclear waste remains radioactive and is hazardous to health for thousands of years.

KEY POINTS

  • Fossil fuels & Nuclear resources are non-renewable
  • Fossil fuels, like coal, oil and gas, take millions of years to develop
  • Fossil fuels are burnt to generate heat, which in turn heats up water into steam to turn a turbine. Generating power. 
  • When fossil fuel is burnt, harmful toxins are released into the air
  • Nuclear power produces toxic waste that must be stored safely for many years. 

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