Q6 — Evaluate replacing a gas-fired power station with a wind farm

A coastal town's gas-fired power station is being decommissioned. The local council is considering replacing it with an offshore wind farm.

Evaluate this decision, considering environmental, economic and reliability factors. Use data where appropriate.

Mark scheme (6 marks — Level of Response):

Level 3 (5–6 marks): Detailed evaluation with balanced advantages AND disadvantages. Includes: zero CO₂ during generation, reduced contribution to climate change / net-zero 2050 target; intermittency (no electricity when wind is too low/too high); higher initial capital cost but lower running cost; decommissioning of turbines and embodied carbon of manufacture; impact on marine ecology and bird populations; comparison of capacity factor (offshore wind ~40%, gas ~85%); reaches a justified conclusion supported by reasoning.

Level 2 (3–4 marks): Some advantages and disadvantages discussed but unbalanced or lacks detail. Limited use of scientific terminology. Conclusion partially supported.

Level 1 (1–2 marks): Simple statements (e.g. "wind is renewable, gas is not"); no real evaluation; no conclusion or unsupported.

0 marks: No relevant content.

Indicative content includes: power output (MW), CO₂ emissions (gCO₂/kWh — gas ~450, wind ~11), variability/storage need, grid balancing, jobs, public perception, planning/visual impact.