ES220719 theoretical test

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POWER PRODUCTION FROM RENEWABLE ENERGY AY 2021-22 19th July 2022 Prof. Paolo Silva Time: 1 hour Instructions for the examination: 1) Clearly indicate your name on all the sheets you will deliver. 2) Give a synthetic and clear answer to as many questions as possible. The final score will be normalized according to the average results. 3) Talk with colleagues and / or cheating will cause the cancellation of the exam. 1. Consider a three-bladed, horizontal-axis wind turbine whose regulation strategy is designed to operate at sea level according to the only measured value of undisturbed wind speed. How would the power curve change if the same turbine is installed at 4000 m asl respectively (i) with no adjustment of the regulation strategy and (ii) with adjustments? 2. Consider a direct geothermal plant exploiting a liquid-dominant source. Explain the reasons why a lamination valve before the demister can be convenient by an energy point of view, despite the irreversibility introduced. 3a. ENERGY AND MECHANICAL ENGINEER- ING STUDENTS: Consider a multi-string PV plant affected by the event depicted in the following picture, where a single panel was displaced by wind whereas the electrical connection is still working. Explain the ex- pected effects in terms of performance and list the single causes of loss originated by the new situation. 3b. MANAGEMENT ENGINEERING STUDENTS: Provide a definition of the Levelized Cost of Elec- tricity (LCOE) for renewable power plants. How is it affected by the availability of the renewable source? What are the other parameters affecting LCOE? 4a: ENERGY ENGINEERING STUDENTS : Consider a medium -head hydro power plant whose flowrate allows the adoption of either a Kaplan or a Francis turbine. Explain the aspects that must be considered to…