nope, if you do not pay for electricity either than you can claim PUE of infinity... Google, Facebook, Yahoo, M$, Sun, SGI and others will be green with envy 
Well, you can claim an impossible PUE of 0 :-)
PUE = facility power / equipment power
If you don't pay, it is as if you provide zero power to the facility, but somehow your equipment gets power anyway... magic yay!