Cars can't run on grit that would be at home on sandpaper, right? They need something that's easy to light and can be sprayed into a combustion chamber. If huge fireballs cannot erupt when tankers carrying it crash, is it really fuel? Yes it is, and this leads to an interesting question.

The blue car shown below in the foreground runs entirely on electricity. As presently delivered by domestic 110-volt wall sockets, electricity can make no huge fireballs, but the plugin time for a complete refuelling is about 32 hours. The vehicle can then go 70 mi/h for 2.6 hours, or 60 mi/h for 3.6 hours.

Montage, foreground Roadster, background Avalanche
Tesla Roadster (foreground) and Chevrolet Avalanche, photoshopped to the same scale

The Roadster is based on a gasoline-burning car, the Lotus Elise. Production has been limited to 2500 by the availability of only that many engineless, fuel-tankless Elises. The electrified version has rocketlike acceleration, and in February 2012 all or nearly all had been sold at a premium, compared to the Elise, of two times its price.

Dividing the extra two Elise prices by the gasoline burned by one Elise in a 200,000-km lifetime, at 35 miles per gallon, yields an estimate of the premium per gasoline-gallon-equivalent: $24.

"Roadsterizing" the Avalanche would reduce its highway run time from about ten hours to three, same as with the Elise, but the corresponding plugin time, for three hours of punching that big a hole through the air, would be 100 hours.

Same range reduction, even slower refuelling. But what if we just reduce normal-sized cars' emissions to zero, without those extras?

No reduction in highway speed and endurance, no loss of independence from electrical outlets, refuelling as quick as ever? Optionally, refuelling at home, since the major side effect we do get is no longer being implicated in fuel tanker fire disasters*?

What per-gallon-equivalent premium would that fetch? That is the interesting question.

Help me download non-free scientific papers (typically about $30), or make the day's rent ($20), or just buy me a beer. Thank you.

Perhaps my prescriptions for the world's problems would be more quickly filled if they were not free. One of these problems is airliners' stratospheric emissions of kerosene-derived oxides: carbon dioxide and water vapour.

The CO2 emissions are a smallish part of total fossil-fuel-derived CO2 emissions, but developing a new generation of airliners fuelled with straight hydrogen wouldn't just solve that relatively small problem. It would also allow faster flights and/or farther ones, because an airliner that, as it takes off, is 40 percent liquid hydrogen by mass has as much energy as one that is 100 percent kerosene. The tanks are larger, but this could be made into an advantage: they could occupy the upper part of the fuselage, so that their contents would shield passengers and crew from cosmic radiation.

None of that is new, and it doesn't solve the problem of high-up water vapour emissions. Water vapour is a greenhouse gas. When our fossil fuel burners emit it, this usually doesn't matter, because they emit it in the troposphere, down where water always promptly rains or snows out, no matter whether it evaporated naturally or was put there by us. It is about as hard to humidify the troposphere by burning hydrocarbons as to make the Zambezi River deeper, just upstream of Victoria Falls, by stationing a firetruck at the base of the cataract and having it drive the flow back up. Stratospheric emissions, though, do not immediately fall back out, and airliners can and do make a lasting difference.

A online auction of an idea for a good solution closed after seven days with no bids. The solution would enable an airliner to take off and land on pure hydrogen, leaving a trail of briefly increased humidity, but once up in the stratosphere, if it flew a route that is already well-travelled, its trail would be one of reduced wetness.

Maybe it's obvious enough that someone else who can work out the details will do so, and disclose them freely. If you want or need to know them, but are not certain that will happen, let me know what opening bid you will put in if I reinstate the auction.

More free stuff: a short 2001 conference paper, and the original web page on boron for surface vehicles, occasionally updated over the past ten years, for instance to discuss related subjects such as VB2-air batteries.

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* If enough fuel to keep a car going for several months or years cannot burn when spilled on the highway, it also cannot burn when stored out back on the driver's property. So refuelling from home might be an attractive option.