Basically it is called Time to Market(TTM). You buy something at a $1 for a future delivery. So when you get the delivery you must charge at least $1.
Unlike electricity, the Oil that we buy has to be shipped to us, refined, and shipped to gas stations. That takes about 30-40 days depending on schedules and delays.
Now you can't take advantage of that fact on a stock exchange because of instantaneous communications (electricity, ie internet) but you can take of advantage of it through the physical product delivery.
And with the shelf life of Non-Ethonal gas at 180 days, and ethanol gas at 90 days. You can even wait for a peak or set margin before you sell.
Currently I am looking into it. I found a 400 Gallon approved container cheep. at 3.63 X 400 = 1448 now a little birdy I know tells me his next purchase is 8 cents more. But a bigger birdy tells me that gas will hit at least a 4.00 average within 60 days. That would be $1600 dollars or a $152 profit.
But I don't want to make money, I just want to Hedge the gas by buy low, and mitigating the costs while it rises by using my own fuel I purchase when it was lower. Not to mention, I get a built in emergency supply.
You are assuming that gas stations price their gas based on what they paid for it, rather than what the expect to pay for their next shipment. They have the same information as you.