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📖 Lesson 13 ⏱ ~30 min Year 9 · Unit 3 ⚡ +100 XP

Non-Renewable Energy Sources

In 2022, Australia exported 360 million tonnes of coal worth $112 billion, energy compressed from ancient plants over 300 million years, released in seconds.

Today's hook: In 2022, Australia's Department of Industry reported that Australia exported approximately 360 million tonnes of coal, earning $112 billion, the nation's largest single export earner. That coal contains chemical energy captured by ancient forests over 300 million years of photosynthesis, compressed and buried, and we release all of it in seconds when we burn it. What exactly are we burning, and what are the true environmental and energy costs?
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Warm-up
Think First
+5 XP each

Q1 · Coal is sometimes called "stored sunshine." Before reading, what do you think that phrase means, where did the energy in coal originally come from, and how did it get there?

Q2 · Australia still exports large amounts of coal and natural gas. If we know fossil fuels cause climate change, why do you think countries keep using them? What would have to change to stop?

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Learning objectives
What you'll master
3 areas

● Know

  • The main non-renewable sources: coal, oil, natural gas, nuclear
  • That fossil fuels formed from ancient organic matter over millions of years
  • The basic energy transformations in fossil fuel power generation

● Understand

  • Why non-renewable sources are finite and their extraction impacts
  • The relationship between burning fossil fuels and CO₂ emissions
  • How Australia's economy depends on fossil fuel exports

● Can do

  • Describe energy transformations in fossil fuel systems
  • Compare renewable and non-renewable sources using multiple criteria
  • Evaluate the environmental and economic trade-offs of energy choices
Cross-lesson links: The energy transformations in fossil fuel power stations connect back to the Sankey diagrams from Lesson 4, you can now draw the full chain from chemical energy in coal to electrical energy at the socket. In Lesson 14 you'll follow that electricity all the way along the transmission grid to your home.
Core learning
5
From the lesson
Energy Mix

🇦🇺 Australia's Electricity Mix, Non-Renewable Focus (2024)

Australia's Electricity Sources Coal 46% Renewables 37% Gas 16% Non-Renewable Facts ⚫ Coal: ~46% of grid 🔥 Gas: ~16% of grid 🛢️ Oil: ~1% (transport) ☢️ Nuclear: 0% in Australia Aus = #1 coal exporter globally Aus = #2 LNG exporter globally Source: AEMO, 2024 data
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⚫ Coal
The powerhouse of Australia's grid
+5 XP

Hold a lump of coal up to light, you are holding energy that travelled 150 million kilometres from the Sun, was captured by a fern leaf 300 million years ago, buried under sediment, compressed by geological pressure for millions of years, and is now waiting to be released in one brief flash of fire. Strike a match to it and all that ancient stored sunshine converts to heat, light, and carbon dioxide in seconds. Fossil fuels are called stored sunshine because they contain chemical energy captured by ancient plants and algae, later transformed by heat and pressure into coal, oil, and natural gas.

These fuels dominate global energy because they are energy-dense, easy to transport, and historically cheap to extract. However, burning them releases carbon dioxide, a greenhouse gas that drives climate change. They are also finite: while reserves may last decades to centuries, they will eventually be exhausted.

Example

A single litre of petrol contains about 34 megajoules of chemical energy, enough to move a car roughly 15 km. This incredible energy density is why liquid fuels remain essential for aviation and long-distance transport despite environmental concerns.

What to write in your book
  • Fossil fuels are ancient organic matter transformed by heat and pressure
  • Coal, oil and natural gas are the main fossil fuels
  • Burning fossil fuels releases stored chemical energy as heat
Flashcards+5 XP

Tap each card to flip. Mark Got it when you can recall the answer without flipping.

0 / 4 mastered
C tap to flip
Coal
When?
USE FOR
Formed from ancient swamp forests. Burns to release chemical energy. Dominant in Australia's grid but being phased out.
O tap to flip
Oil
When?
USE FOR
Formed from marine microorganisms. Used for transport fuels, plastics and chemicals. Highly energy-dense.
G tap to flip
Natural Gas
When?
USE FOR
Formed alongside oil and coal. Burns cleaner than coal. Used for heating, cooking and electricity generation.
N tap to flip
Nuclear
When?
USE FOR
Energy from splitting uranium atoms. No direct carbon emissions. Australia has no nuclear power stations.
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🔥 Natural Gas
Cleaner than coal, but still fossil
+5 XP

Photosynthesis is the original energy capture process. Plants convert sunlight, water and carbon dioxide into glucose, storing solar energy in chemical bonds. When those plants die and are buried, their chemical energy remains trapped. Over millions of years, heat and pressure concentrate that energy into fossil fuels.

So when you burn coal or petrol, you are really releasing solar energy that arrived on Earth hundreds of millions of years ago. The difference between fossil fuels and biofuels is simply the timescale: fossil fuels are ancient stored carbon, while biofuels are recently stored carbon.

Example

A piece of coal might contain energy from sunlight that fell on a Carboniferous swamp forest 300 million years ago. That energy has been locked in chemical bonds ever since, waiting to be released.

What to write in your book
  • Photosynthesis captures solar energy in chemical bonds
  • Buried organic matter transforms into fossil fuels over millions of years
  • Burning fossil fuels releases ancient stored solar energy
Why is coal called stored sunshine?
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🛢️ Oil (Petroleum)
The transport fuel that powers a nation
+5 XP

Not all fossil fuels are equally polluting. Natural gas produces roughly half the carbon dioxide of coal per unit of energy, which is why some countries have switched from coal to gas as a bridging fuel. However, gas is still a fossil fuel and still contributes to climate change.

Nuclear energy is often grouped with fossil fuels in policy discussions, but it is fundamentally different. Nuclear power uses fission of uranium atoms to release energy, producing no direct carbon emissions. The challenges are waste disposal, high capital costs, and public concern about accidents.

Example

France generates about 70% of its electricity from nuclear power, giving it one of the lowest carbon intensities of any major economy. Australia, despite having the world's largest uranium reserves, has never operated a nuclear power station.

Real-world anchor

The Australian Energy Council notes that coal still provides around 50% of Australia's electricity, but this share is declining as renewables and storage become cheaper. Natural gas provides flexible backup generation during peak demand.

What to write in your book
  • Natural gas produces less CO2 per unit energy than coal
  • Nuclear power has no direct carbon emissions but produces radioactive waste
  • Australia has significant reserves of coal, gas and uranium
Two are true, one is a lie. Pick the lie.
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☢️ Nuclear + Environmental Impact
The debate Australia avoids
+5 XP

While geological processes do continue to form fossil fuels, the rate is thousands of times slower than our consumption. We are effectively mining a stockpile that took hundreds of millions of years to accumulate. On any human-relevant timescale, fossil fuels are non-renewable.

Beyond scarcity, the climate impact of burning fossil fuels creates an even stronger imperative to transition. The carbon dioxide released was removed from the atmosphere over geological time; returning it over centuries disrupts the climate system.

Example

Global oil consumption is approximately 100 million barrels per day. No geological process can replenish that rate. Even if we discovered new reserves equal to everything we have ever found, we would still face the climate consequences of burning them.

What to write in your book
  • Fossil fuels form thousands of times slower than we consume them
  • Burning fossil fuels releases carbon dioxide that drives climate change
  • Transitioning away from fossil fuels is a scientific and policy priority
True or false?
Fossil fuels will last forever because Earth constantly produces new oil and coal.
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From the lesson
Interactive
Interactive, Carbon Calculator

🎮 Estimate your household's annual CO₂ from electricity

Monthly electricity bill ($) $ / month
Electricity cost per kWh $ / kWh
Grid carbon intensity
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From the lesson
Copy Into Your Books

Copy Into Your Books

▼

Coal

  • Chemical → Thermal → Kinetic → Electrical
  • ~33-40% efficient (brown coal lower)
  • ~0.85 kg CO₂ per kWh
  • Australia: #1 exporter globally

Natural Gas

  • Chemical → Thermal → Kinetic → Electrical
  • ~50-60% efficient (CCGT)
  • ~0.40 kg CO₂ per kWh
  • Australia: #2 LNG exporter globally

Oil (Petroleum)

  • Chemical → Thermal → Kinetic (transport)
  • ~20-45% efficient (vehicle engines)
  • ~0.25-0.27 kg CO₂ per kWh mechanical
  • Australia imports 80% of oil needs

Nuclear

  • Nuclear → Thermal → Kinetic → Electrical
  • ~33% efficient
  • Near-zero CO₂ during operation
  • Australia: largest uranium reserves, no nuclear power
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From the lesson
Activity 1
Identify + Apply

Energy Transformation Chains

For each non-renewable technology, write the complete energy transformation chain. Name the energy form at each stage and the object/substance that has it.

1 A coal-fired power station in the Latrobe Valley, Victoria.

✏️ Answer in your book.

2 A natural gas combined-cycle turbine at a power station in Queensland.

✏️ Answer in your book.

3 A petrol-powered car driving on the Hume Highway between Sydney and Melbourne.

✏️ Answer in your book.
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From the lesson
Activity 2
Evaluate + Recommend

The Transition Challenge

The town of Morwell in Victoria's Latrobe Valley has relied on coal for 100 years. The Hazelwood power station closed in 2017, and Loy Yang is scheduled to close by 2047. Using what you have learned about non-renewable and renewable energy sources, recommend an energy transition plan for Morwell. For each source you recommend, explain why it suits this location and describe the energy transformations involved. Consider: existing workforce skills, land availability, transmission infrastructure, and environmental impact.

✏️ Design and justify in your book.
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From the lesson
Additional content
Reflect
Revisit your thinking
reflect

At the start of this lesson you were told that coal is literally compressed ancient sunshine, photosynthesis captured solar energy hundreds of millions of years ago, and we release it all in seconds by burning it. Australia exports around 400 million tonnes of coal every year.

Now that you've explored the true costs of unleashing that stored energy, has your view on fossil fuels changed? What surprised you most about the environmental and economic trade-offs?

Interactive Tool, Renewable Energy Sources Open fullscreen ↗
Fossil fuels are non-renewable because they:
Quick check · multiple choice
1
Quick check
Which energy transformation chain correctly describes electricity generation at a coal-fired power station?
+10 XP
2
Quick check
A natural gas combined-cycle power station is approximately 60% efficient, while a coal power station is approximately 35% efficient. For the same electrical output, how much less CO₂ does the gas station produce per kWh compared to coal?
+10 XP
3
Quick check
Why is oil (petroleum) rarely used for electricity generation in Australia?
+10 XP
4
Quick check
Australia has the world's largest uranium reserves but no nuclear power stations. Which of the following best explains this situation?
+10 XP
5
Quick check
A family switches from a coal-heavy electricity grid (0.85 kg CO₂/kWh) to a renewable-dominated grid (0.05 kg CO₂/kWh). Their home uses 20 kWh per day. Approximately how much CO₂ do they save per year?
+10 XP
0
From the lesson
Short Answers
SA
Written Response

Short Answer Questions

Use clear scientific language. Check the model answers after attempting each question.

3 marks

Question 1. A coal power station burns 250 tonnes of black coal per hour to generate 500 MW of electricity. The coal contains 25 MJ of chemical energy per kilogram. Calculate the efficiency of the power station. Show all working and state the efficiency as a percentage.

✏️ Answer in your book.
Hint: Convert 250 tonnes to kilograms first. Calculate total input energy = mass × energy per kg. Calculate output energy = power × time. Efficiency = (output ÷ input) × 100.
4 marks

Question 2. A student claims: "Natural gas is the perfect solution because it produces half the CO₂ of coal and is very efficient. We should build more gas power stations and stop worrying about renewables." Evaluate this claim, providing at least one argument supporting the claim and at least two arguments challenging it. Use specific scientific evidence from this lesson.

✏️ Answer in your book.
Hint: Consider that gas is still a fossil fuel. What about methane leaks? What about the finite supply? Can gas stations run without fuel deliveries? What happens when gas runs out?
5 marks

Question 3. Australia is the world's largest coal exporter and second-largest LNG exporter, earning over $150 billion annually from fossil fuel exports. At the same time, Australia has committed to net-zero emissions by 2050. Explain the tension between Australia's economic dependence on fossil fuel exports and its climate commitments. Your answer should refer to specific energy transformations, efficiency differences between sources, and the concept of finite resources.

✏️ Answer in your book.
Hint: Think about the jobs and revenue from exports versus the emissions. Consider that renewable energy cannot be exported in the same way as coal or LNG (though hydrogen might change this). What happens to export revenue when other countries stop buying fossil fuels?
Model answers (click to reveal)

Model Answers

▼
Q1 (3 marks)
Step 1: Mass of coal = 250 tonnes = 250,000 kg. Energy per kg = 25 MJ. Total chemical energy input per hour = 250,000 × 25 = 6,250,000 MJ = 6.25 × 10⁶ MJ. (1 mark)
Step 2: Power output = 500 MW = 500 MJ/s. Time = 1 hour = 3,600 s. Electrical energy output per hour = 500 × 3,600 = 1,800,000 MJ = 1.8 × 10⁶ MJ. (1 mark)
Step 3: Efficiency = (1,800,000 ÷ 6,250,000) × 100 = 28.8% ≈ 29%. (1 mark)
Marking criteria: (1) Correctly calculates total chemical energy input (6.25 × 10⁶ MJ). (2) Correctly calculates electrical energy output (1.8 × 10⁶ MJ). (3) Correctly calculates and states efficiency (~29%).
Q2 (4 marks)
Supporting argument: Natural gas CCGT is approximately 60% efficient versus coal at 33–40%. Gas produces approximately 0.4 kg CO₂/kWh compared to coal's 0.85 kg CO₂/kWh. This represents a genuine emissions reduction. Gas plants can also start quickly, making them useful backup for intermittent renewables. (1 mark)
Challenge 1: Natural gas is still a fossil fuel. Methane (the main component) is itself a potent greenhouse gas, 80 times more powerful than CO₂ over a 20-year period. Leaks during extraction and transport can offset much of the combustion advantage. The Scarborough gas field alone would release 1.4 billion tonnes of CO₂ equivalent. (1 mark)
Challenge 2: Natural gas reserves are finite. Australia may have 300 years of coal but only 30–50 years of economically recoverable gas at current rates. Building new gas infrastructure locks in fossil fuel dependence for decades, delaying the transition to genuinely sustainable energy. When gas runs out, the infrastructure becomes stranded. (1 mark)
Conclusion: While gas is cleaner than coal, it is not a long-term solution. It may play a transitional role, but investment should prioritise renewables and storage rather than new fossil fuel infrastructure. (1 mark)
Marking criteria: (1) Valid supporting argument with efficiency/CO₂ data. (2) Challenge 1 (methane leaks or finite supply). (3) Challenge 2 (different challenge with evidence). (4) Balanced conclusion recognising transitional role only.
Q3 (5 marks)
Economic dependence: Australia's fossil fuel exports earned over $150 billion in 2023, coal ($65 billion) and LNG ($90 billion). These exports support 150,000 direct jobs and fund government services. The Bowen Basin, Hunter Valley, and North West Shelf are economic heartlands. Transitioning away threatens regional economies. (1 mark)
Climate commitments: Australia has committed to net-zero by 2050. Coal produces 0.85 kg CO₂/kWh; LNG produces 0.4 kg CO₂/kWh. Australia's domestic emissions are approximately 400 million tonnes annually, with coal responsible for the largest share. Export emissions (when coal/LNG are burned overseas) are not counted in Australia's domestic total but contribute to global climate change. (1 mark)
Energy transformation differences: Coal: chemical → thermal → kinetic → electrical at 33–40% efficiency, with 60–67% waste thermal + CO₂. Gas CCGT: same chain but 50–60% efficient with less CO₂. Renewables (solar/wind): bypass combustion entirely, light/kinetic → electrical directly. This fundamental difference means renewables have near-zero operational emissions regardless of efficiency. (1 mark)
Finite resource challenge: Coal and gas formed over 300 million years from ancient organic matter. Current extraction rates deplete reserves in decades to centuries. Unlike renewable sources (solar, wind) that are naturally replenished, fossil fuels cannot be replaced on human timescales. Australia's economic model relies on selling a finite resource that the world is trying to stop using. (1 mark)
Conclusion: The tension is genuine and complex. Australia's economy depends on exporting fossil fuels, but climate science demands their phase-out. The transition requires new export industries (green hydrogen, critical minerals, renewable technology) and support for affected communities. Delaying transition increases both economic and climate risk. (1 mark)
Marking criteria: (1) Explains economic dependence with specific data. (2) Explains climate commitments with emissions data. (3) Compares energy transformations and efficiency. (4) Explains finite resource challenge. (5) Balanced conclusion recognising complexity.
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From the lesson
Additional content
Quick-fire challenge
Game time
+25 XP
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From the lesson
📚 Revisit the Content

📚 Revisit the Content

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Energy Mix Coal Natural Gas Oil Nuclear Carbon Calculator
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