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S6 Geography Energy Resource Management Paper 4: Error Review
S6 Geography Energy Resource Management Paper 4: Error Review
Ten original error-review items, each with an answer and a one-line explanation.
Direct answers Items 1-3 revisit energy mix shares and per-capita use, 4-6 cover capacity factor, wind output and emissions, 7-9 apply avoided emissions, payback and import dependence, and item 10 separates percentage points from relative change. Cover the answers first, then check each note.
01 Paper details (check answers afterwards)
| Item | Detail |
|---|---|
| Questions | 10 |
| Suggested time | 20 |
| Difficulty mix | Foundation 3 · Intermediate 3 · Challenge 3 · Error redo 1 |
| Chapter | Chapter: S6 Geography: Energy Resource Management |
| Level | S6 |
02 Questions (10 items)
- FoundationError review: an energy mix is coal 40%, gas 25%, nuclear 15% and renewables 20%. What do the shares add up to?
- FoundationError review: a city uses 120 000 GWh a year with a population of 6 million. What is consumption per person in kWh?
- FoundationError review: the renewable share rises from 8% to 22%. By how many percentage points did it rise?
- IntermediateError review: a wind farm could generate 8 760 MWh a year in theory but delivers 2 190 MWh. What is its capacity factor?
- IntermediateError review: a 2 MW turbine runs effectively for 2 000 hours a year. What is its annual output in MWh?
- IntermediateError review: coal emits 0.90 tonnes of carbon dioxide per MWh. How much is emitted for 500 000 MWh?
- ChallengeError review: if 20% of that 500 000 MWh came from zero-carbon sources, how many tonnes of carbon dioxide would be avoided?
- ChallengeError review: a solar system costs 60 000 dollars and saves 5 000 dollars a year. What is the payback period?
- ChallengeError review: a country uses 400 TWh a year and imports 70% of it. How much is imported?
- Error redoError review: a pupil writes that a share rising from 15% to 20% is a rise of 5%. What is wrong and what is the correct wording?
03 Answers and one-line notes
| # | Answer | One-line note |
|---|---|---|
| 1 | 100% | 40 + 25 + 15 + 20 = 100; the shares of an energy mix must total 100. |
| 2 | 20000 kWh | 120 000 GWh is 1.2 x 10^11 kWh, and dividing by 6 million gives 20000 kWh; GWh and kWh differ by a factor of a million. |
| 3 | 14 percentage points | 22 – 8 = 14 percentage points; saying it rose by 14% confuses points with relative change. |
| 4 | 25% | 2 190 / 8 760 x 100 = 25%, and a low capacity factor is a typical limit of wind power. |
| 5 | 4000 MWh | 2 MW x 2 000 h = 4000 MWh; using 8 760 hours would assume full output all year. |
| 6 | 450000 tonnes | 0.90 x 500 000 = 450000 tonnes; multiplying by a further 1 000 mixes tonnes with kilograms. |
| 7 | 90000 tonnes | 100 000 MWh is replaced, so 0.90 x 100 000 = 90000 tonnes avoided; using the full 500 000 MWh overstates it. |
| 8 | 12 years | 60 000 / 5 000 = 12 years; ignoring maintenance and efficiency loss, the real period is usually longer. |
| 9 | 280 TWh | 400 x 70% = 280 TWh, and a high import share means weaker energy security. |
| 10 | a rise of 5 percentage points | 20 – 15 = 5 percentage points; the relative increase is 5 / 15, about 33 per cent, and the two must not be mixed. |
04 What to do after marking
- After marking, redo only the wrong items and write down which step went wrong (formula, unit, or misread number).
- Repeat the same item two days later; move to the next paper only when both attempts are correct.
- Parents only need the answer and note columns; there is no need to explain every item.
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