What does “net energy” mean as it pertains to ethanol production?
The term “net energy” is used extensively by both advocates for and opponents against ethanol production. It has become a simplified way to express whether the energy produced by burning ethanol is greater or less than the energy of all the inputs required to produce the ethanol. If the net energy number is positive, it suggests that the ethanol produces more energy than it took to produce it and vice versa. The reason there are such a wide range of opinions on this number is related to the inputs used in the equation. Energy numbers can vary substantially for such things as plant efficiency and design, chemical fertilizer production, farm equipment and practices, and the values assigned to co-products. The baseline net energy number for gasoline from crude oil is generally accepted to be 4.52, while gasoline from oil sands is 1.69. The net energy for ethanol produced from corn is 1.56. A study recently completed by the company publishing these net energy numbers assigns a net energy o
