A tidal barrage produces an average power output of 240 MW240\ \text{MW}240 MW.
A company wants to build a wind farm to produce the same average power output.
Each wind turbine has a maximum power output of 3.0 MW3.0\ \text{MW}3.0 MW. On average, each wind turbine produces only 35% of its maximum power output.
Calculate the number of wind turbines needed.
Explain why a tidal barrage is a more reliable energy resource than a wind farm.
Even if enough wind turbines are built, a gas-fired power station is still needed.
Explain why.
Give one environmental disadvantage of building a tidal barrage.
16 exam-style questions on OCR GCSE Physics 8.2 Powering Earth, covering 8.2.1 Renewable and non-renewable energy resources, 8.2.2 Patterns and trends in energy use, 8.2.3 The national grid, 8.2.4 Step-up and step-down transformers, 8.2.5 Efficiency of the national grid, 8.2.6 Transformers and power transmission at high voltage, 8.2.7 The UK domestic supply, 8.2.8 Direct and alternating potential difference, 8.2.9 Live, neutral and earth wires, and 8.2.10 Dangers of mains electricity. Each one has a worked solution and a mark scheme showing where the marks go.