Non-Renewable Energy Sources

Coal is a sedimentary rock formed from the compressed remains of ancient swamp plants that lived 300 million years ago. Over geological time, heat and pressure transformed plant matter into peat, then lignite (brown coal), then bituminous coal (black coal), and finally anthracite — the highest grade.

Australia has vast coal reserves — approximately 147 billion tonnes, enough to last over 300 years at current production rates. The Bowen Basin in Queensland and the Hunter Valley in NSW are Australia's coal heartlands. In 2023, Australia exported 185 million tonnes of metallurgical coal (for steelmaking) and 190 million tonnes of thermal coal (for electricity). These exports earned $65 billion, making coal Australia's second-largest export after iron ore.

Coal power stations are approximately 33–40% efficient. A typical 1,000 MW station burns 300 tonnes of coal per hour — equivalent to the weight of 50 African elephants. The energy transformation chain is: chemical → thermal → kinetic → electrical. The remaining 60–67% becomes waste thermal energy (heating cooling water) and CO₂ emissions. A 1,000 MW coal station emits about 8 million tonnes of CO₂ annually — equivalent to the emissions of 1.7 million cars.

Natural gas is primarily methane (CH₄), formed from the remains of marine microorganisms that settled on ancient seabeds. Over millions of years, heat and pressure transformed this organic matter into natural gas trapped in underground rock formations.

Natural gas power stations are significantly more efficient than coal stations. A modern combined-cycle gas turbine (CCGT) reaches 60% efficiency — almost double that of coal. Gas also produces about half the CO₂ per kilowatt-hour: approximately 0.4 kg/kWh for gas versus 0.9 kg/kWh for coal. This is why gas is often described as a "transition fuel" — it can replace coal while renewables scale up.

Australia is the world's second-largest exporter of liquefied natural gas (LNG), after Qatar. The North West Shelf project off Western Australia has been operating since 1989 and remains one of the largest LNG facilities in the world. In 2023, Australia exported 81 million tonnes of LNG, earning $90 billion — surpassing coal as Australia's most valuable energy export. The gas is cooled to −162°C, where it becomes liquid and shrinks to 1/600th of its volume, enabling economical transport by specialised tanker ships to Japan, South Korea, and China.

Crude oil is a liquid fossil fuel formed from ancient marine organisms. Like natural gas, it formed under heat and pressure over millions of years. Oil is rarely used for electricity generation in Australia — instead, it dominates transport: cars, trucks, ships, and aircraft.

Refineries process crude oil into useful products through fractional distillation. The different hydrocarbon molecules in crude oil have different boiling points. When heated, they separate into fractions: petrol (C₅–C₁₂, boils at 40–180°C), diesel (C₁₂–C₂₀, boils at 180–370°C), kerosene (jet fuel), and heavy fuel oil for ships. A typical barrel of crude oil (159 litres) yields approximately 72 litres of petrol, 32 litres of diesel, and smaller amounts of other products.

Australia's oil production has declined dramatically. In 2000, Australia produced 85% of its oil needs domestically. By 2023, that figure had fallen to 20%. The Bass Strait fields — which powered Australian transport for 50 years — are now nearly depleted. Today, Australia imports 80% of its oil, mostly from Singapore, Malaysia, and the Middle East. This creates a significant energy security risk: Australia holds only 60 days of oil reserves, well below the International Energy Agency's recommended 90 days.

Nuclear energy generates electricity through nuclear fission: splitting uranium-235 atoms releases enormous heat energy with no direct CO₂ emissions. A single uranium fuel pellet the size of a fingertip contains as much energy as 1 tonne of coal. Nuclear power stations are approximately 33% efficient, similar to coal, but their emissions are negligible during operation.

Australia has the world's largest known uranium reserves — 1.7 million tonnes, about one-third of global resources. The Olympic Dam mine in South Australia is the world's largest uranium deposit. However, Australia has never operated a nuclear power station. The Nuclear Non-Proliferation Treaty and domestic policy have prevented nuclear power development. The debate resurfaces periodically: proponents argue nuclear could provide reliable, zero-carbon baseload power; opponents cite high costs (nuclear plants cost $10–15 billion each), long construction times (10–15 years), and the challenge of radioactive waste storage.