Energy Diagram for Propane I've been unable to find an energy diagram for propane either in my book or online via Google. So I resorted to making my own. I suspect that propane isn't covered because it's essentially the same deal as ethane - we can have one staggered conformation and one eclipsed conformation (only in propane it's a methyl eclipsing a hydrogen, not hydrogens eclipsing each other). 

So I drew the Newman projections and an energy diagram.
Your diagram is correct.  Here is a link to an on-line energy diagram for propane and here is the diagram itself