Answer to Question #275182 in Electrical Engineering for Kedi

Question

1.1 Medupi power station uses coal of calorific value of 5880 kcal/kg to generate electricity. They use 14.3 tonnes of coal every 25 minutes to generate the maximum demand of the power station. The thermal and electrical efficiency of the power station are 24.2% and 81.1%, respectively. The cost of purchasing the coal is R800 per tonne.

1. Determine the overall efficiency of the power station (%). 

Answer 1

The overall efficiency of the power station:

$$\eta=\eta_t\eta_e=0.242·0.811=0.196,\text{ or 19.6\%}.$$