I just ran across this spreadsheet/program which is free from Argonne
Labs that models the well to wheels efficiency along with greenhouse gas
emissions for various input parameters (fuel source, vehicle type,
etc.). As near as I can tell you can go in and compare, for example,
hydrogen fuel cell cars using hydrogen from renewable energy to hybrid
diesel using biodiesel from soybeans or any other combination.
Aside from an inordinate number of acronyms I think students could
probably use it without too much difficulty: