An engineer is planning the electricity supply for an isolated city. She wants to make the system as energyefficient and environmentally friendly as possible, but her options are limited. The two options she isconsidering are as follows.
Option 1: coal-burning power station on a coal field approximately 300 km from the city, with high-voltage transmission lines between them. Option 2: diesel power station in the city, generating power at the desired voltage (250 V AC)In Option 1, the efficiency of the various stages in the process is as follows.
• efficiency of the generating plant (coal to electricity) - 60%
• efficiency of the long-distance, high-voltage transmission lines - 90%
• efficiency of the transformers to convert high voltage to 250 V in the city - 90%
In Option 2, the diesel power station is approximately 60% efficient (oil fuel to electricity, ready to use). What percentage of the coal's energy reaches the city?