11. Answer ALL parts of this question. (a) Describe the theory of the formation of geothermal reservoirs. List two main features of geothermal systems for renewable energy production. (4 marks) (b) The power of radiation emitted by the Sun is 3.8 1026 W spread in all directions. A solar observation satellite orbits the Sun at a distance of 70 x 108 km from the Sun and requires 1500 W to operate. Calculate: 0 The irradiance on the satellite's sun-facing side along its orbit around the Sun in W m2 (6) The surface area of solar panels required by the satellite to produce all its power, assuming 20% efficiency. (5 marks) (c) Briefly describe, with appropriate examples, the process of doping materials to make n-type and p-type semiconductors. (4 marks) (d) A parabolic trough collector power station A parabolic trough collector power station has the following characteristics: heat transfer fluid temperature = 400 C, condenser temperature = 30 C, solar concentration ratio = 80, emissivity (8) = 0.2 (thermal), absorptivity (A) = 0.9 (optical). Draw a labelled diagram to illustrate the power balance around the solar collector and calculate the maximum efficiency of the power station under AM1.5. (5 marks) (e) A wind turbine has the features shown in FIGURE Q1e. Thrust, Rotor diameter 6m 434ms! V. -4ms FIGURE Q1e Density of air is 1.25 kg m?. Using information from FIGURE Q1e and the relevant formulae in the APPENDIX, calculate: 0 The air velocity at the rotor, U2 ) The axial induction factor (a) for this turbine c) The pressure at either side of the rotor (P2 and Pa) (iv) The power output from the turbine. (7 marks)