why is gas cheaper in Alberta?

07.11.11: We just returned from the stampede yesterday and I couldn't help but wonder why gas was approx 18% cheaper in Calgary (same for other Alta cities).
The current price is approx $1.07 ... confirmed with my iPhone GasBuddy app just now.


Did a quick google search - to no avail.


Anyone know if it is just provincial taxes or what other variables are involved?


p.s. Hard to talk about global warming - or reducing dependency on fossil fuels - with Albertans ...