If you measure energy in British thermal units BTUs and if 1

If you measure energy in British thermal units (BTUs), and if 15,000 BTUs of fossil energy are used to produce corn ethanol, how many BTUs will the resulting corn ethanol contain? How many BTUs will cellulosic ethanol contain? How many kWh of energy does the corn ethanol contain? Refer to figure below:

Solution

FER = Energy Delivered To Customers / Fossil Energy Used

From the graph,

FER of Corn Ethanol = approx 1.5

FER of Cellulosic Ethanol = approx 5.1

Energy content or deliverable by corn ethanol = 1.5 x Fossil Energy Used

= 1.5 x 15000 BTU = 22,500 BTU

= 22500 x 1.05506 KJ = 23738.757 KJ

= 23738.757 / 3600 KWh = 6.5941 KWh

Energy content or enegy deliverable by Cellulosic Ethanol = 15000 x 5.1 BTU = 76500 BTU