Unit 4 Area of Study 2 of VCE Environmental Science requires students to compare energy sources across multiple dimensions: environmental impact, reliability, economic cost, energy density and sustainability.
Global energy use drives:
- ~75% of global greenhouse gas emissions
- Significant land, water and material resource consumption
- Air and water pollution affecting human health and ecosystems
- Geopolitical tensions over resource control
The transition from fossil fuels to lower-emission alternatives is central to both climate mitigation and achieving sustainability principles.
When comparing energy sources, consider:
| Dimension | Description |
|---|---|
| Greenhouse gas emissions | CO$_2$e per kWh generated (lifecycle) |
| Energy density | Energy content per unit mass or volume |
| Reliability/dispatchability | Can supply be controlled and matched to demand? |
| Land use | Area required per unit energy generated |
| Water use | Cooling water and process water requirements |
| Resource depletion | Are inputs renewable or finite? |
| Pollution | Air, water, soil, thermal impacts |
| Cost | Capital, operating and decommissioning costs |
| Social impacts | Jobs, health, community acceptance |
| Feature | Non-Renewable (fossil fuels) | Renewable |
|---|---|---|
| Resource finite? | Yes | No (within human timescales) |
| GHG emissions | High (coal > oil > gas) | Low to zero (operational) |
| Energy density | High (reliable) | Variable (depends on source) |
| Dispatchability | High (on-demand) | Variable (solar, wind) or high (hydro, biomass) |
| Land use per kWh | Relatively low (excluding mining) | Generally higher (solar, wind) |
| Waste issues | CO$_2$, SO$_2$, particulates; nuclear waste | Limited (depends on source) |
Australia’s electricity grid is rapidly transitioning:
- Coal still generates a large share of electricity (declining)
- Renewable energy capacity (solar and wind) increasing rapidly
- Natural gas provides intermediate load and backup
- Rooftop solar: Australia has among the highest per capita rooftop solar installation globally
Sustainability challenge: Maintaining grid reliability as variable renewable sources increase their share requires storage (batteries, pumped hydro) and grid management investment.
STUDY HINT: When comparing energy sources in VCAA exams, use a clear structure: name the source, describe how it generates electricity, identify its key advantages and disadvantages, and evaluate it against relevant sustainability principles. Always include both ecological and economic dimensions.
