(FORTUNE Magazine) – Zooming gas prices, plus the usual bad news from the Middle East, naturally raise the question: What else can we do? Quite a lot, actually. And if the price of oil sticks above $40 a barrel, the dynamics change. The analysts at Cambridge Energy Research Associates think that unconventional oils (like the sands) could account for one-third of supply by 2020, vs. 22% today. The unconventional category also includes oil harvested by ultra-deep-water offshore platforms (2,500 feet plus) and drilling ships that can operate at ocean depths as great as two miles in the Gulf of Mexico and elsewhere.

Then there is shale oil, a crude obtained from oil shale by heating and distillation. It's been the stuff of dreams for decades, and at today's prices, could finally make economic sense. World reserves are estimated at 2.6 trillion barrels--two trillion located in the good old U.S.A., though Australia has gone the furthest in tapping the resource. And the natural-gas boom is resulting in increasing supplies of liquid fuels known as natural-gas liquids or condensates, which are separated from natural gas at processing plants. One of these, propane, can fuel vehicles in place of gasoline.

For those looking to replace oil, not just to find more of it in odder places, ethanol and other biofuels are getting new attention. Although in the U.S. ethanol from corn has a reputation both for draining energy and being corporate welfare, high oil prices make it more interesting. The recent energy bill provided a guaranteed market for 7½ billion gallons by 2012. This ugly duckling may yet become a swan.

Unsubsidized producers in Brazil are already making oceans of biofuel from sugar cane. An energy-equivalent quantity of ethanol brewed there sells for less than half the price of crude oil. More than half the new cars sold in Brazil can run on fuels ranging from straight gasoline to straight ethanol. And researchers around the world are experimenting with all sorts of plant oils--including canola, soybean, and palm--to fuel diesels, which can't burn ethanol.

Bottom line: The service station of the future is going to have a menu of options. Oil made from garbage, anyone?