Gas pumpEnlarge Photo
Natural gas probably has the most potential beyond electricity, since it's widely used and there is at least some household availability in some regions. Building natural-gas fueling stations with any kind of comprehensive coverage, however, would be a major challenge.
Some analysts expect NGVs to be limited to certain duty cycles: Long-haul truckers who can fill up at regularly spaced Interstate rest stops, for example, or local commuter vehicles in areas like the LA Basin.
Ethanol tough, hydrogen very tough
Ethanol in its most concentrated E85 form cannot be distributed through the current gasoline system (it eats rubber seals and other components, as it does in engines that aren't designed for Flex-Fuel use) so it must be carried in separate trucks, kept in separate tanks, etc.
That's one reason it's much easier to distribute ethanol blended into gasoline (as E10 or the upcoming E15 that the EPA has just approved for certain models) than as E85. (The number after the "E" indicates the overall percentage of ethanol in the liquid.)
Honda Solar Hydrogen Station prototype with 2010 Honda FCX Clarity hydrogen fuel-cell vehicleEnlarge Photo
And hydrogen, though energy-dense and emissions-free, has the worst distribution problems of all. General Motors found that it took more than 2 years and close to $2 million to get permission to build a single hydrogen fueling station in White Plains, NY.
Multiply that by the 15,000 stations you'd need for minimal national coverage, and you're getting into the tens of billions of dollars--without even asking where the hydrogen might come from.
In other words, nothing's easy.
Which wins on price?
It's almost impossible to predict the relative costs of driving a mile on gasoline, a gas-ethanol blend, natural gas, or grid power 10 years hence. That's because it largely depends on the price of oil, which will make the default fuel--gasoline--more or less attractive.
In the short term, government subsidies play a large role in kick-starting sales of alt-fuel vehicles. The Bush and Obama Administrations have instituted various programs of low-interest loans and grants to encourage investment in fuel-efficiency and lithium-ion cell technology.
There are also tax credits up to $7,500 for buyers of plug-in cars, and state, regional, and corporate entities offer various additional incentives on top of those.
gas PricesEnlarge Photo
If oil rises gradually but steadily, there may be less desire by consumers to switch than if it spikes as it did in 2008, then collapses. Some evidence indicates that the volatility of oil-price change is more important than the actual level. Think of it as the "frog in a pot of cold water" theory.
No energy plan
In the U.S., what's lacking is a long-term vision on how we can reduce our dependence on oil for transportation. Decades from now, for example, oil may have higher and better uses (like being made into plastics) than being burned for vehicle fuel.
Right now, ethanol backers (largely Midwestern agricultural interests) have one vision, natural-gas backers (e.g. T. Boone Pickens) have another, the growing electric-vehicle lobby has a third, and no coherent policy exists to coordinate it.
We have no national goal, no space-shot effort, no pledge to cut energy use 5 percent in one year and 30 percent in a decade. The best time for such a goal--when the nation was willing to do anything in the weeks after 9/11--was utterly wasted by an administration that urged its citizens only to resume shopping as normal.
Perhaps the free market will sort it out in the end. But that would be easier with accepted metrics to evaluate the results of tests, new technologies, and incentives. If policymakers and the public could weigh the efficiency of alternatives, look at results, compare and weigh the costs, results, and prognoses, we might make progress quicker.
Toyota Prius at US Capitol, by Flickr user IzikEnlarge Photo
But the current political climate in the U.S. would seem to preclude enactment of a comprehensive long-term energy plan. Instead, we now have various mandates (e.g. the ethanol requirement), subsidies (e.g. the plug-in tax rebates), research programs, and other Federal and state regulations.
Instead, we're likely to see a slow evolution to more efficient gasoline vehicles. Plug-ins will increase in numbers, reaching noticeable percentages by the end of the decade, and natural-gas may be an option for some buyers. But if you're an average U.S. driver, don't expect to give your gas station a miss any time soon.