
116 Principles of Sustainable Energy Systems
one unit of energy is used to decommission the system. The energy produced is 25 units,
and the net energy output for this system is 20 units. Thus, the EROI for this example is 5.
In Figure 2.8, the shaded area of energy input during the operational lifetime includes the
energy of the fuel input for a fossil or nuclear plant. If this were a renewable electricity gen-
eration plant that did not require energy fuel or decommissioning, the EROI would be 12.5.
A key difference between the EROI for fossil or nuclear generating systems and renew-
able technologies, such as solar or wind, is the fact that the ...