Answer:
The energy yield for one gallon of ethanol is 2.473 %.
Explanation:
The net energy yield ([tex]\% e[/tex]), expressed in percentage for one gallon of ethanol is the percentage of the ratio of the difference of the provided energy ([tex]E_{g}[/tex]), measured in Btu, and the energy needed to produce the ethanol ([tex]E_{p}[/tex]), measured in Btu, divided by the energy needed to produce the ethanol. That is:
[tex]\% e =\frac{E_{g}-E_{p}}{E_{p}} \times 100\,\%[/tex] (1)
If we know that [tex]E_{g} = 76330\,Btu[/tex] and [tex]E_{p} = 74488\,Btu[/tex], then the net energy yield of 1 gallon of ethanol:
[tex]\%e = \frac{76330\,Btu-74488\,Btu}{74488\,Btu}\times 100\,\%[/tex]
[tex]\%e = 2.473\,\%[/tex]
The energy yield for one gallon of ethanol is 2.473 %.