Two vehicles implement different approaches to using ethanol as a fuel.
One vehicle burns the ethanol in an internal combustion engine with an efficiency of 18% to convert the chemical energy in the ethanol to mechanical energy supplied to the vehicle's wheels. The second vehicle uses electricity to charge batteries to run electric motors to drive the wheels. The electricity is produced by burning the ethanol in a heat engine to drive a generator with a net efficiency of 38%. The batteries/electric motors are 89% efficient. (a) Compare the relative amounts of ethanol needed for the two vehicles to travel the same distance.
(b) Compare the relative net $\mathrm { CO } _ { 2 }$ emissions for the two vehicles.

Question

Quizplus · Accepted Answer

The Answer of Two vehicles implement different approaches to using ethanol as a fuel.
One vehicle burns the ethanol in an internal combustion engine with an efficiency of 18% to convert the chemical energy in the ethanol to mechanical energy supplied to the vehicle's wheels. The second vehicle uses electricity to charge batteries to run electric motors to drive the wheels. The electricity is produced by burning the ethanol in a heat engine to drive a generator with a net efficiency of 38%. The batteries/electric motors are 89% efficient. (a) Compare the relative amounts of ethanol needed for the two vehicles to travel the same distance.
(b) Compare the relative net $\mathrm { CO } _ { 2 }$ emissions for the two vehicles.

Two Vehicles Implement Different Approaches to Using Ethanol as a Fuel