A sustainable energy future must meet three criteria simultaneously: lower greenhouse gas emissions (for climate), reliability (security of supply) and affordability (accessible to all). VCE Environmental Science identifies four key strategies.
Current global energy systems face a structural problem:
- ~80% of energy comes from fossil fuels
- These fuels generate ~75% of global GHG emissions
- Maintaining reliability during transition to renewables is technically and economically complex
- Energy access is unequal — billions lack reliable energy
What it means: Getting more economic output or human well-being from each unit of energy consumed.
Examples:
- Industrial processes: Combined heat and power (cogeneration) captures waste heat for industrial heating — improves overall efficiency from ~35% to ~80%
- Buildings: Improved insulation, double glazing, thermal mass reduce heating and cooling energy demand
- Smart grids: Match supply and demand in real time, reducing wastage and grid losses
- Urban design: Compact cities with efficient public transport reduce per capita energy use for transport
- Agricultural efficiency: Precision irrigation and fertiliser application reduce energy inputs per unit food produced
Sustainability connection:
- Efficiency of resource use principle: directly satisfied
- Reduces total resource extraction and associated environmental impacts
- Cost-effective — often the cheapest ‘source’ of new energy is energy saved
What it means: Using technology to convert energy with less waste at each step.
| Device | Old Efficiency | New/Best Available | Improvement |
|---|---|---|---|
| Incandescent bulb | ~5% (light:input) | LED: ~20–30% | 4–6× |
| Simple steam turbine | ~25–35% | Combined-cycle gas: ~60% | 2× |
| Electric motor (old) | ~80% | High-efficiency motor: ~95% | |
| Petrol car engine | ~20–25% | Best ICE: ~40% | 2× |
| Solar panel (1980s) | ~10% | Commercial 2024: ~22–25% | 2.5× |
Key technologies:
- LED lighting — most cost-effective efficiency improvement globally; 90%+ of countries now transitioning
- Heat pumps — use electricity to move heat (rather than generate it); effective efficiency (COP) of 2–5 means 200–500% conversion efficiency
- High-efficiency electric motors — industrial motors are the largest single electricity-consuming technology globally
Sustainability connection:
- Reduces total fuel combustion and associated GHG emissions per unit of energy service
- Applies first and second law of thermodynamics — minimises entropy losses
What it means: Transitioning electricity generation, heating, transport and industry from fossil fuels to renewable and nuclear sources.
What it means: Behavioural and lifestyle changes that reduce individual energy demand.
Examples:
- Transport: Cycling, walking, carpooling, public transport instead of private car
- Dietary choices: Plant-based diets require 2–10× less energy than meat-heavy diets
- Home energy: Turn off standby appliances; use cold water washing; reduce unnecessary air conditioning
- Consumer choices: Buy fewer goods; choose durable products; repair rather than replace
- Flying less: Long-haul aviation is difficult to decarbonise; reducing air travel is one of the highest-impact individual actions
Co-benefits: Many personal consumption reductions also improve health (active transport, plant-based diet) and reduce costs.
Limits: Individual action alone cannot decarbonise the global economy — systemic changes in energy infrastructure, urban design and industrial processes are also required.
| Strategy | Reduces emissions? | Improves reliability? | Reduces cost? |
|---|---|---|---|
| Resource efficiency | Yes (less fuel needed) | Yes (less demand to supply) | Yes (less energy to buy) |
| Conversion efficiency | Yes | Indirectly | Yes (less fuel per kWh) |
| Fuel switching (renewables) | Yes | Depends on storage/grid | Increasingly yes |
| Personal consumption reduction | Yes | Yes (less load) | Yes |
A comprehensive sustainable energy transition deploys all four strategies simultaneously.
EXAM TIP: VCAA may ask you to evaluate one or more of these strategies in terms of feasibility, sustainability principles, and stakeholder trade-offs. Structure your answer: describe the strategy → link to a sustainability principle → identify limitations or trade-offs → suggest complementary strategies.
