I admit I am no engineer either. But as a practicing chemist and self-avowed "natural philosopher" (in the seventeenth-century sense) I am familiar with engineering principles.
I grant that diesel fuel in its current form and use is dirty. But I maintain that its unsurpassed energy density and ease of mechanical transduction (a Diesel engine is a pretty simple piece of equipment, once you allow for the industrial skill in its actual manufacture). I further believe (until convinced otherwise) that gas or diesel power can be easily matured to a very clean state.
I was not restricting myself to lead-acid batteries. Nickel metal hydride batteries, experimental sodium-sulfur batteries, etc. all rely on internally stored fuel and oxidizer to generate electrochemical energy. As a result, the laws of physics and chemistry restrict batteries to pretty low energy densities. This means that if you want one horsepower-hour of energy, you're gonna have to lug around a lot of pounds of battery to store it. All the technology in the world will only allow you to approach that energy density theory figure from below.
Flywheels and [ultra]capacitors have one fatal flaw imho. They cannot be proofed against instantaneous discharge. If the energy of one gallon of gas or diesel were instantaneously discharged (after admixing the right amount of air) the energy release would equal that of a fourfold weight of high explosive. That's fifteen kilos of plastique, and what that will do to a car and its surrounding twenty-meter radius... does not make a polite topic. They are potentially useful as short-distance drives (like a kilometer or less) but for a car or truck - I just don't see it.
I will further opine that the author's statement that alternative energy vehicles "are... ultimately the only potion" is not factual. In fact, it smells of politics to me. I have suggested that hydrocarbon vehicles can be made greenhouse neutral by recycling carbon-bearing fuel from the atmosphere. Plants can be conveniently used to bind solar energy (perhaps the ultimate "green power" source) in oil form. Veggie oil makes excellent diesel! As for non CO@ emissions - were already there with gas engines. The current Honda Accord four-cylinder is a practical, affordable car which passes muster as a Zero Emissions Vehicle. Of course its emissions aren't zero - but a poor diet by a passenger is liable to double them. :-)
I don't doubt that specialist electric cars have been built to go 600 miles on a charge. But I'll wager that the specific power requirement of such a car is very, very low. With such a low specific power requirement, a microdiesel could be built to the same weight and maybe do the NY-CA run. (I think the highest fuel mileage recorded from a specialty research car is better than 1300 mpg. But that is one of those one-man teardrops running on bicycle wheels - not exactly family fare.)
To me (jmho of course) the SciAm article proves one thing in spades. Electric and alternative-power vehicles are riding a wave of popularity out of proportion to their technical "executability". The story "between the lines" in this article is that to mature these technologies to an economic level may be impractical or just never happen. I place it on the same level as popular-science articles from my youth, some thirty years ago, which promised a car-sized personal aircraft in every garage in the near future. The exuberance of those authors, indeed the Sixties-innocent embracement of the mythos of technical Progress, was not yet subjected to the "reality check" of real-life physics and economics.
Those twin shoals will be a tough strait for E-cars to navigate. |
