Evaluating energy sources
Big idea: No energy source is perfect. Choosing an energy mix requires balancing multiple factors: environmental impact, reliability, cost, scalability, and social acceptance.
Evaluation criteria
- GHG emissions: Lifecycle carbon footprint (extraction → use → disposal)
- Air pollution: SO₂, NOₓ, particulates, mercury
- Water use: Cooling, extraction, processing
- Land use: Footprint per unit energy produced
- Reliability: Baseload capability, intermittency, capacity factor
- Cost: Levelized cost of electricity (LCOE)
- Scalability: Can it meet large-scale demand?
- Energy return on investment (EROI): Energy output ÷ energy input
Comparing sources
- Fossil fuels: Reliable, cheap, scalable — but high emissions, pollution, finite
- Nuclear: Low carbon, reliable, high density — but waste, safety, cost concerns
- Solar/wind: Low emissions, decreasing cost — but intermittent, need storage
- Hydro: Reliable, controllable — but site-limited, ecosystem impacts
- Geothermal: Reliable baseload — but geographically limited
Exam tip: The energy essay is highly predictable. Prepare a table comparing at least 4 sources across 5+ criteria. Practice writing balanced evaluations with clear conclusions.
Energy transitions and EVSs
Big idea: Different environmental value systems (EVSs) lead to different energy preferences — from technocentric faith in nuclear and CCS to ecocentric emphasis on efficiency and demand reduction.
EVS perspectives on energy
Technocentric approaches
- Nuclear power as climate solution
- Carbon capture and storage (CCS)
- Large-scale renewable projects
- Continued economic growth possible
- Technology will solve problems
Ecocentric approaches
- Demand reduction and efficiency
- Small-scale, distributed renewables
- Opposition to nuclear (waste/risk)
- Question growth model
- Lifestyle and system change needed
The energy transition
- Current status: Fossil fuels still ~80% of global energy; renewables growing rapidly
- Challenges: Intermittency, storage, grid infrastructure, stranded assets, political resistance
- Opportunities: Falling renewable costs, climate urgency, air quality co-benefits, energy independence
- Policy tools: Carbon pricing, renewable targets, fossil fuel subsidy reform, R&D investment
The energy transition is not just technical — its also economic, political, and social. Vested interests, infrastructure lock-in, and lifestyle expectations all create barriers.
Exam tip: Link energy choices to EVSs explicitly. E.g., A cornucopian would support nuclear expansion, believing technology can manage waste safely.