Question

1. Question #2 of Assignment 9 involved an electrical generation system including a generator with an efficiency of 98%, a transmission line with a 94% efficiency, and finally a light bulb with a 12% conversion efficiency. Suppose that instead of coal, the primary energy for the same system is provided by wind turbines that have a 45% efficiency, or solar cells with a 23% efficiency.

   a) Does the full energy conversion sequence using these renewable sources make significantly more efficient use of the primary energy available? Explain why or why not. [2 Marks]. b) For the fossil fuels, a consequence of low efficiency is that to provide a given amount of energy to customers much more energy, in the form of raw resources, has to be extracted from the ground. For example, to deliver 1000 MJ of electrical energy using coal requires an input of roughly 3000 MJ of primary energy in the form of coal. What is a practical consequence of lower efficiency for renewable resources like wind and solar? In other words, how might 1000 MJ of electrical energy be delivered to customers using wind or solar facilities? Explain. [2 Marks]

Answer 1