Why are gas prices so different at Calgary gas stations right now?

A recent surge in gas prices on the Prairies was largely unrelated to the gas tax. Instead, a refinery shutdown in Joliet, Illinois led to a shortage of gas and diesel in the US Midwest, prompting people to import more fuel from Alberta via the Enbridge mainline. This situation resolved itself when the refinery restarted mid-last week, causing gas prices to decline in the region. Gas stations typically purchase fuel in advance, so they may try to sell existing inventory at a higher price to maintain their profit margins.

A 30-cent price difference within a single city is indeed remarkable. While I don't usually shop around for gas, a 75% cost savings by driving ten minutes to fill up is a compelling reason to make the trip.