Site energy is what your utility meter would read -- it is the energy
used on the site.
Source energy takes into account energy loss for production and
transmission -- so it is the raw energy entering the power plant. Your
site to source conversion for electricity depends on your electrical
generation source. Recall that most thermal electric generating
stations are ~33% efficient ("Carnot efficient"?) in terms of
electricity out over fuel in.
Site energy is what your utility meter would read -- it is the energy
used on the site.
Source energy takes into account energy loss for production and
transmission -- so it is the raw energy entering the power plant. Your
site to source conversion for electricity depends on your electrical
generation source. Recall that most thermal electric generating
stations are ~33% efficient ("Carnot efficient"?) in terms of
electricity out over fuel in.
Portfolio Manager has great information on this. Brian is spot on in his
description. You can google Portfolio Manager and FAQs.