The IGCSE Physics syllabus requires you to compare energy resources using a range of criteria. No single resource is best in every category; the choice depends on local conditions and priorities.
Comparison criteria
| Criterion | What to consider |
|---|---|
| Reliability | Can it provide power on demand, or is it intermittent? |
| Environmental impact | Greenhouse gases, pollution, land use, habitat disruption |
| Running cost | Fuel costs, maintenance, staffing |
| Initial cost | Construction of the power station or installation |
| Power output | How much electricity can it generate? |
| Location requirements | Does it need wind, sunlight, water, or a specific geography? |
| Fuel supply | Is the fuel finite or replenished? |
Summary comparison
| Resource | Reliable? | CO2 during operation | Power output | Fuel cost |
|---|---|---|---|---|
| Coal | Yes | High | High | Moderate |
| Natural gas | Yes | Moderate | High | Moderate |
| Nuclear | Yes | None | Very high | Low |
| Solar | No (intermittent) | None | Low per unit | None |
| Wind | No (intermittent) | None | Low per unit | None |
| Hydroelectric | Yes (if reservoir) | None | High | None |
| Geothermal | Yes | Very low | Moderate | None |
The role of energy mix
Most countries use a combination of resources (an energy mix) to balance reliability, cost and environmental impact. Renewable resources reduce carbon emissions but require backup from reliable sources when output is low.
Worked example
Explain why a country might choose to build both a gas-fired power station and a wind farm.
The gas-fired station provides reliable base-load power that is not affected by weather. The wind farm reduces the amount of fossil fuel burned and lowers overall carbon emissions. Together, they balance reliability with environmental responsibility.
Common errors and how to correct them
Stating that one resource is “the best” without qualification. Every resource has trade-offs. Always justify the comparison with specific criteria.
Using vague language like “bad for the environment” without explaining how. State the specific impact: carbon dioxide emissions cause climate change; sulfur dioxide causes acid rain; radioactive waste requires secure long-term storage.
How to apply this in an exam
Structure comparison answers by criterion. Use a table if space allows. Give specific advantages and disadvantages for each resource mentioned, not generic statements.
Need help with this concept?
A 0625 specialist can work through the student's current question and help identify whether the difficulty is the concept, the calculation or the exam technique.