Edmonton Gas Variance

Anyone noticing an increasing discrepancy across the city for gas prices lately? I have lived in Edmonton a long time and have never seen such a wide difference for no apparent reason. My wife and I have taken to calling it the south side tax, as gas prices are regularly 10+ cents higher in this area than other parts of the city. 133.9 in the west end today, 147.9 by my house. Unfortunately this seems to be the new normal. Is there any reason for this beyond greed?