Earth's resources - renewable & non-renewable

What you will learn

the difference between renewable and non-renewable resources,
major examples used in Australia and worldwide,
how resources are extracted (mining, drilling, harvesting),
benefits and risks of fossil fuels, nuclear, and renewable energy,
what “sustainability” means and how it is measured.

Worked example 0 Real-world example: the family home

A household gets its hot water from a gas heater, its electricity from the grid (mostly coal in Victoria), and its cooking gas from natural gas. Classify each energy source and suggest one renewable replacement for each.

Gas hot water: natural gas — non-renewable fossil fuel. Replace with a solar hot-water system or a heat pump powered by renewable electricity.
Grid electricity from coal: non-renewable. Replace with solar PV on the roof or a green-power plan (wind/solar from the grid).
Gas cooking: non-renewable. Replace with an electric induction cooktop powered by renewable electricity.

Key idea: any fossil fuel is non-renewable on human timescales because it takes millions of years to form.

1. Renewable vs non-renewable

A renewable resource replenishes quickly enough (at human timescales) to keep up with use, if we manage it well.

Solar, wind, hydroelectric, tidal, geothermal.
Biomass (wood, crops) — renewable if replanted as fast as harvested.
Water (in a properly managed catchment).

A non-renewable resource exists in a fixed or very slowly replenished amount. Once used, it is effectively gone.

Fossil fuels: coal, oil, natural gas (formed over hundreds of millions of years from ancient living things).
Nuclear fuels: uranium (a limited ore in the Earth’s crust).
Metals and minerals: iron, aluminium, copper, gold (though many can be recycled).

2. How resources are extracted

Different resources need different extraction methods. Each involves benefits (useful material) and risks (environmental cost).

Resource	Extraction method	Example location	Main risk
Coal	Open-cut or underground mining	Latrobe Valley (VIC), Hunter Valley (NSW)	CO $_2$ emissions, habitat loss
Iron ore	Open-cut mining	Pilbara (WA)	Dust, landscape destruction
Natural gas	Drilling (onshore or offshore)	Bass Strait (VIC)	Methane leaks, ocean pollution
Uranium	Hard-rock or in-situ leaching	Olympic Dam (SA)	Radioactive waste
Timber	Logging	Tasmania, Victorian Central Highlands	Deforestation, biodiversity loss
Wind energy	Wind turbines	Macarthur Wind Farm (VIC)	Visual impact, some bird strikes
Solar energy	Solar PV panels	Rooftops, Bungala (SA) solar farm	Land use, panel disposal

3. Energy production: benefits and risks

Coal-fired power

Benefits: cheap at scale, reliable 24/7, large existing workforce.
Risks: high CO $_2$ emissions (climate change), air pollution, mining impacts, cannot be “refilled.”

Natural gas

Benefits: cleaner-burning than coal, quick to switch on.
Risks: still a fossil fuel; methane leaks are a strong greenhouse gas.

Nuclear

Benefits: almost no CO $_2$ at the point of power generation; a small amount of fuel releases huge energy.
Risks: radioactive waste (tens of thousands of years); rare but severe accidents; high build cost.

Solar / Wind

Benefits: no direct emissions; fuel is free; modular (scales from rooftop to grid).
Risks: variable (depends on sun/wind); storage or backup needed; manufacturing uses mined materials.

Hydroelectric

Benefits: reliable, long-lasting, can store energy by pumping.
Risks: dams flood habitats; affect fish migration.

Worked example 1 Comparing choices

A new power station is planned. Option A is a coal plant; option B is a solar farm with battery storage. List two advantages and two disadvantages of each.

Option A (coal). Advantages: delivers power day and night; uses established technology. Disadvantages: high CO $_2$ emissions; coal runs out; air pollution.
Option B (solar + battery). Advantages: no emissions during operation; fuel (sunlight) is free. Disadvantages: depends on sunny weather; batteries and panels need minerals that are mined.

Key idea: “best” is rarely one-sided. Decisions trade off climate impact, cost, reliability, and land use.

4. Sustainability

Sustainability means meeting today’s needs without preventing future generations from meeting theirs.

Three key ideas:

Rate of use $\leq$ rate of renewal (for renewable resources).
Reduce, reuse, recycle to stretch non-renewable resources.
Replace high-impact resources with lower-impact alternatives wherever possible.

Worked example 2 A sustainability audit

A school uses 30 000 kWh of electricity from coal-based grid power and throws away 2 tonnes of paper per year. Suggest three sustainability improvements and justify each.

Install rooftop solar to replace a share of grid electricity — reduces fossil fuel use and bills.
Set printers to double-sided by default — roughly halves paper use (reduce).
Run a paper-recycling program — paper becomes pulp for new paper, cutting new-tree demand.

Key idea: sustainability is usually achieved by many small changes that add up, not one big fix.

5. Recycling and the circular economy

Metals such as aluminium and copper can be melted down and reused indefinitely. Recycling aluminium uses about 5% of the energy needed to make it from bauxite ore. A circular economy tries to keep materials in use rather than sending them to landfill, effectively turning non-renewable materials into much longer-lasting resources.

Worked example 3 Energy saved by recycling

Making aluminium from ore uses about $200$ MJ per kg. Recycling uses about $10$ MJ per kg. Estimate the energy saved per kilogram recycled, and the percentage saving.

Energy saved $= 200 - 10 = 190$ MJ/kg.
Percentage saving $= \dfrac{190}{200} \times 100\% = 95\%$ .
Recycling aluminium saves roughly $95\%$ of the energy compared with making it new.

Practice: Year 8

Fluency

Classifying resources

Classify each as renewable or non-renewable: (a) wind, (b) coal, (c) uranium, (d) solar, (e) timber (managed forest), (f) natural gas.
Name two fossil fuels.
Give an Australian example of a coal mine, an iron-ore mine, and a solar farm.
What is the main greenhouse gas released by burning fossil fuels?
Why are metals sometimes called “recyclable” rather than renewable?

Fluency

Extraction and production

What method is used to extract coal? Iron ore? Natural gas?
State one benefit and one risk of nuclear power.
Why are wind and solar described as variable energy sources?
Explain how a hydroelectric dam generates electricity.
List two environmental risks of open-cut mining.

Reasoning

Explain and evaluate

Explain why fossil fuels are classed as non-renewable even though new oil is still occasionally discovered.
A politician says “nuclear is clean because there is no smoke.” Evaluate this claim.
Describe two reasons replanting trees after logging is important for sustainability.
Compare coal and solar on three criteria: CO $_2$ emissions, fuel cost, and reliability.

Problem solving

Applied contexts

A family uses 6500 kWh of electricity per year. A 5 kW rooftop solar system produces about 7000 kWh per year in Victoria. Would this cover their usage? What other factor matters?
A mining company wants to open an iron-ore mine next to a river. List two environmental impacts they should plan to manage.
A community is choosing between adding a new coal generator or a wind farm. Suggest three questions the community should ask before deciding.
Explain, using the idea of a circular economy, why placing aluminium cans in the yellow bin reduces demand for bauxite mining.

Challenge

Reasoning

Harder reasoning

A country’s electricity mix is $70\%$ coal, $20\%$ gas, $10\%$ renewables. A new target is $50\%$ renewables within 10 years. Suggest three policies that would help reach this target and predict one challenge each might create.
Groundwater is a renewable resource, but only if used sustainably. Explain why overuse can cause permanent damage to an aquifer even if some rain still recharges it.
A lifecycle assessment of a product tracks its impacts from raw-material extraction to disposal. Explain why comparing only “running” emissions of two cars (e.g. petrol vs electric) can be misleading.
“Non-renewable” is defined relative to a human timescale. Use this idea to explain why uranium, which is found in tiny amounts throughout Earth’s crust, is still called non-renewable.