solved!

big news!  worked out a stupid problem that i have been staring at for days!  finally just wussed out and broke the equation into pieces - and it got rid of the 3-orders-of-magnitude issue.  i was feeling like an idiot - but it turns out that while my ideas were correct, my equation editing is apparently subpar (will have to hire people for that bit, i suppose).  yes, yes, yes - checked it against similar data, and it's dead on.  i kinda thought it would be difficult to get 800 kilos of CO2 out of one kilo of natural gas. 

huge geek.  most exciting thing i've done in days.