Question 1: Define renewable energy and give two examples of renewable energy sources.

Answer: Renewable energy is energy from sources that are naturally replenished on a human timescale, such as solar and wind energy.

Question 2: Explain how solar panels convert sunlight into electricity.

Answer: Solar panels use photovoltaic cells to convert sunlight into electrical energy through the photoelectric effect.

Question 1: A solar panel has an area of 2 m² and receives an average solar irradiance of 1000 W/m². If the panel has an efficiency of 15%, calculate the maximum power it can generate.

Answer: Power = Area × Irradiance × Efficiency = 2 m² × 1000 W/m² × 0.15 = 300 W

Question 2: A wind turbine has a swept area of 2000 m². If the average wind speed is 12 m/s and the air density is 1.225 kg/m³, calculate the theoretical maximum power extractable from the wind using the formula: Power = 0.5 × air density × swept area × wind speed³. (Use SI units).

Answer: Power = 0.5 × 1.225 kg/m³ × 2000 m² × (12 m/s)³ = 0.5 × 1.225 × 2000 × 1728 ≈ 2,119,680 W or approximately 2.12 MW

Question 1: Describe two safety precautions that should be taken when installing a wind turbine.

Answer: Ensuring proper grounding to prevent electrical hazards and installing safety barriers to prevent falls during maintenance.

Question 2: Identify one variable that could affect the efficiency of a solar thermal system and suggest a method to optimise it.

Answer: Variable: Angle of the solar collector; optimisation: adjust the angle seasonally to maximise sunlight absorption.

Question 1: A community installed solar panels with a total capacity of 150 kW. Over a sunny day, they produce an average of 600 kWh. Calculate the average power output during daylight hours and comment on the efficiency if the sunlight was available for 8 hours.

Answer: Average power = Total energy / hours = 600 kWh / 8 hours = 75 kW. The system's efficiency depends on the incident sunlight and actual panel performance, but assuming maximum capacity is 150 kW, the average output is 50% of maximum.

Question 1: Explain how offshore wind farms benefit from stronger and more consistent wind speeds compared to onshore wind farms.

Answer: Offshore wind farms benefit from stronger and more consistent wind speeds because open sea areas experience less turbulence and higher wind velocities, leading to increased energy generation and improved efficiency.

Question 2: Discuss two advantages and one challenge of using bioenergy as a renewable resource.

Answer: Advantages include the ability to produce energy from waste materials and carbon neutrality, as the CO₂ released is balanced by the CO₂ absorbed during plant growth. A challenge is the land use requirement, which can compete with food production and lead to deforestation if not managed sustainably.