This essay addresses the following question: Can an auto mobile be built which will be energy efficient and pollution free? The answer to this question depends largely upon the definition of automobile, energy efficient, and pollution free. Depending upon the definitions of these terms, and how they are combined, the answer could correctly be yes, probably, perhaps, or never.
If pollution free, as an example, is defined literally to mean that the power plant of the vehicle emits no environmen tally harmful substances into the air in any quantities what ever, the answer would likely be never. If, on the other hand, pollution free is defined to mean that emissions would be con tained below the levels found to be a threat to human health, and below the levels found to be harmful to other forms of life, then the answer would be at least perhaps, and maybe even yes, depending upon the definitions applied to the terms energy efficient and automobile.
The term energy efficient may also be defined in several contexts. One way to approach the definition of energy effic ient is to develop a ratio of usable energy to the amount of the energy source consumed, and then to apply some arbitrary designation of what is and is not efficient. As an example, suppose that an automobile power plant could obtain an output of 80 percent of the amount of an energy source consumed as usable energy, and the arbitrary standard for energy efficiency was a ratio of 75 percent. One would then have an energy efficient automobile. If the efficiency standard were set at the 90 percent level, however, one would have an energy inef ficient automobile. Another approach to defining the term energy efficient is to arbitrarily establish an operational performance standard, in term of miles per gallon of fuel, as an example. Already on the market are automobiles powered with internal combustion engines which can deliver 50 miles per gal lon of gasoline in highw...