News and Views for the Week of May 4

Recently I've gotten a number of press releases from an organization called WorldAutoSteel which turns out to be a division within the International Steel Institute, a trade organization serving the steel industry. It seems that the Institute has its eye on the future, and it sees a world where two ton gas guzzlers may not be as welcome as they once were, but where the ultra light steel auto body, a concept being promoted by the Institute, might meet with a somewhat warmer reception.

So what is the ultra light steel auto body? It's just what you think it is, an approach to building light with traditional structural materials which will end up saving lots of fuel, or so the Institute maintains.

Today just about everyone subscribes to the notion that fuel economy has become a pressing issue because of the high degree of likelihood that high oil prices are here to stay. So if motor fuel is going to continue to be dearer than it was during the Clinton Administration, which appears to be the case, then motorcars are going to have to curb their appetites somewhat. Obviously one can accomplish that goal to some degree simply by changing their power plants, but one can further decrease fuel consumption by reducing moving mass, improving aerodynamics, and eliminating in so far as possible losses due to mechanical friction. And if all these measures are taken simultaneously, the greatest improvements in efficiency will be realized.

The power plant tends to get the most attention, probably because the public has been led to believe that miracles can be achieved by changing it. Auto makers are notably less likely to suggest that vehicle curb weights can be reduced because the manufacturers are not over eager to follow those proven procedures that will meet that objective, and because their own political lobbyists have succeeded in convincing the public that lightweight vehicles are inherently unsafe.

And yet the WorldAutoSteel organization has come along and stated that a safe, practical sedan auto body of normal proportions but weighing less than 200 kilograms exclusive of the doors can be constructed almost entirely of steel, the auto industry's material of choice for more than a hundred years. And they've issued technical papers to show exactly how it's done.

The design team hired by WorldAutoSteel has actually built prototypes, so they're not just blowing smoke. The whole project is a serious proof of concept demonstration. But how on earth do they manage to achieve an approximately 75% reduction in mass?

Well, a big part of the approach consists of utilizing some new ultra high strength steels as the basic structural materials, in other words, this isn't your father's steel unibody. Unfortunately, they're not saying just how much these new super steels cost compared to the old established alloys. Now there's a guy in Texas who sells a recreation of the famous Damascus steel from the Middle Ages for thousands of dollars per pound. Some steel costs as much as silver in fact. Now I would assume that because a number of major auto manufacturers are sponsoring this effort, the actual steel used in the prototypes is not some extravagantly priced "unobtainium". But we won't really know the bottom line until some auto manufacturer decides to take this or some parallel approach to reducing body mass.

I am convinced that some approach or approaches to making significantly lighter vehicles will become established in the mid term whether or not they are based on steel construction. Our own emphasis here is on alternative fuels as the solution to our transportation problems, but it seems likely that any alternative will be costly compared to Clinton era gasoline, and that consequently fuel economy will be of paramount importance. The question is how to maximize fuel efficiency within a cost effective consumer product, and how specifically will weight savings to that end be achieved?

Achieving a high degree of structural integrity while minimizing weight has always been the preoccupation of the aircraft industry, and has also obsessed the manufacturers of racing vehicles for terrestrial and marine use. So it's not as if we're lacking in prior art. The problem has been that airplanes, race cars, and race boats are essentially cost-is-no-object artifacts, and, on that basis, rather poor models for the automotive mass market to follow. Still, I believe, the basic overall design strategies utilized in these exorbitantly expensive vehicles can be instructive.

The Science of Strong Light Materials

Typical mass produced automobile bodies are made from a combination of heavy gauge sheet steel and thick, heavy structural steel girders that comprise the frame. Ordinary automotive grade steel is pretty cheap today and there's little incentive to scrimp especially when to do so may involve many additional expensive machining operations, which is why automobile bodies are so massive.

In high performance sportscars, where maintaining a favorable power to mass ratio is important, carbon fiber, sheet aluminum, and, in the past, fiberglass have been substituted for steel in a process termed "lightweighting" by Amory Lovins, a well known writer on energy topics and director of the Rocky Mountain Institute. (Lovins himself, who has had aspirations to be an auto maker, favors carbon fiber.)

But in fact no production passenger automobile made today is really optimized for practical weight savings. Even where the car is an expensive limited production item, as is the case with exotic sports cars, the cost constraints are generally more stringent than is the case with an airplane or luxury speedboat and thus the vehicle will have as many standard structural components as possible. Very seldom will the vehicle be designed from the ground up for lowest possible mass while maintaining structural strength and safety.

I have actually found that the most acute analyses of matters of structural strength, mass, and durability take place within a tiny and arcane sub-segment of the transportation industry, that cottage industry of impassioned obsessives concerned with the fabrication of custom bicycle framesets for road racing. The frame itself is a simple but elegant truss structure that has already been highly optimized for its function of mounting the drive train and steering mechanism and supporting the rider, and thus the only real design choices are in the wall thickness and cross sectional dimensions of tubular (or approximately tubular) members that go to make up the frame, and in the materials used to construct those members. Racing bike framesets have been constructed of steel, aircraft aluminum, carbon fiber, boron fiber, foamed aluminum sheets, titanium, magnesium, and even bamboo, and have even utilized fractal micro-trusses in place of thin walled tubes. The range of experimentation has been astonishing. So what can it tell us about the design of auto bodies and the future of structural steel within that industry? That's a topic for a future article, but for now I'll make one observation which generally holds true for virtually all approaches to "lightweighting" and which can be readily supported with examples from the bicycle industry. Successfully reducing mass while maintaining structural strength and durability is primarily accomplished by the artful distribution of stresses over the surface of the vehicle so as to marshal all or most of the structural material for the task of resisting mechanical forces that might cause vehicle to fail. It is also accomplished by minimizing the deployment of said structural materials within unstressed or lightly stressed members or locations. And if such strategies can be executed within micro-structures or nano structures, so much the better.

Carbon Sequestration Takes a Hit- Sort of

Last week the energy pubs also gave a lot of coverage to one Anders Hansson, a doctoral candidate in Linkoping University's Department of Technology and Social Change, who recently completed a dissertation devoted to the subject of carbon sequestration which we touch upon in this journal from time to time. Ordinarily, doctoral dissertations go unnoticed by the press, but Hansson is unusual in already having published several influential papers regarding energy and the environment as a graduate student and having achieved a reputation of sorts even before completing his professional credentials.

Hansson has not published the document as yet, nor has he defended it before his dissertation committee (an academic rite of passage in which the committee and the candidate often end up getting blind, stinking drunk), but he certainly has publicized it and its chief findings such as they are. "It's overly optimistic to place such great faith in it [carbon sequestration]," Hansson asserts. "In full scale this technology only exists in the imaginations of the people developing it."

And here we were looking to carbon sequestration as a solution to our global warming problems….

Actually, I'm eager to see the dissertation in order to determine if it contains any important new data concerning the subject. Hansson is right in stating that CO2 sequestration is not fully proven, especially as a carbon mitigation strategy, but in fact quite a bit of carbon dioxide has been stored for long periods of time in reservoirs in the western United Sates where it is kept on tap, so to speak, for use in enhanced oil recovery operations. This has been going on since the early seventies, and the data from the field indicates that the reservoirs are pretty stable.

CO2 storage specifically for the purpose of carbon abatement is quite rare, however, and only a handful of sites exist around the globe though several new ones are under construction.

The real problem as I see it is the scarcity of suitable sites. Only certain types of geological formations are good for this purpose, and they're not found everywhere and certainly not everywhere the biggest point source emitters are located. In order to store carbon dioxide safely underground we would have to construct vast, dedicated pipelines to transport the carbon dioxide from the places where it is being produced to the relatively few places where it can be stored safely.

Now as a matter of fact CO2 can also be stored in the depths of the ocean where it forms stable clathrates at abyssal depths, but advocates of this approach are predictably few since the mere mention of it arouses fears of global catastrophe among the environmental community. I am rather curious as to whether Mr. Hansson considers this approach in his tome.

At any rate, whether or not carbon sequestration is well considered, the pace with which it is being implemented today does not suggest that it will have any serious impact on CO2 concentrations in the atmosphere within the foreseeable future. It is one of those policy initiatives like promoting clean coal or cellulosic ethanol which simply aren't being embraced with any degree of seriousness. Something to calm an electorate concerned with climate change and high fuel prices, but not something to make any claims on the national treasure.

Indeed, I believe that there is an excellent chance that the U.S. will take no actions whatsoever to address CO2 buildup in the atmosphere in the years to come including putting in place a carbon sequestration policy. I am betting heavily that John McCain will win the Presidential election, and I am also betting that he will abandon his support for carbon caps. McCain recently indicated that former Defense Secretary James Schlesinger will be advising his campaign on energy issues, and Schlesinger is a notorious global warming denier. Furthermore, McCain has taken heat from the right wing punditocracy on his recent support for carbon mitigation measures, and has been accused of abandoning conservative principles by doing so. His policy in the past has been to capitulate to such opinion makers on every issue where he has previously expressed differences with the conservative mainstream. I would expect that a McCain Administration would follow an energy policy that is very similar to that of the Bush Administration, though he could prove more aggressive in appropriating the energy resources of occupied Iraq.

Doing nothing to address global climate change is actually a very safe policy to pursue in the near term, as it is unlikely that South Florida is going to be flooded in three or four years. High fuel prices are a different matter, however, and I am uncertain as to how McCain will confront that issue. We will simply have to wait and see.

A New DME Engine Design

If one were going to design a practical policy for liquid transportation fuels based upon existing technology rather than pipedreams, then that policy would probably favor di-methyl ether (DME), a simple carbohydrate with the same composition as ethanol but with a different molecular structure.

DME, especially when mixed with ethanol, works extremely well in high efficiency compression ignition engines, and produces less CO2 than any other liquid motor fuel. It can be easily and cheaply produced from coal by proven means, and can also be fairly inexpensively manufactured from natural gas and biomass. Better yet, it is entirely nontoxic and in fact is used as a propellant for aerosol sprays for administering medications.

DME's only real drawback is its energy density which is only about half that of diesel. While it is gaseous at ambient pressures it liquefies under moderate compression and is normally stored as a liquid. Obviously special fuel tanks are required for it. It can't simply be substituted for petroleum diesel as can biodiesel.

Last week the journal Energy & Fuels reported that a new type of engine for DME is under development at Sanghai Jiao Tong University. It uses a combination of port fuel aspiration as in an ordinary gasoline engine and direct injection like virtually all modern diesels. The engine is said to achieve homogenous charge combustion which means that the entirety of the air fuel mixture within the cylinder is ignited all at once rather than progressively by an advancing flame front. Homogenous charge combustion results in very low NOX emissions which are the bane of traditional compression ignition engines while still achieving excellent fuel efficiency.

From my perspective the claimed benefits of the technologies under development are of less interest than the fact that the Chinese government is sponsoring work in this area and allowing the results to be published. This, I warrant, is a signal that China may be seriously considering promoting DME as a transportation fuel. At the end of 2006 China began publishing standards for methanol motor fuel for use in spark ignition engines, and methanol, as it happens, is easily converted into DME. Both may be inexpensively manufactured from coal which China possesses in abundance, and the economics for either fuel are much better than is the case for Fischer-Tropsch synfuels or any other coal-to-liquids technologies of which I am aware. But DME would be ultimately a better choice than methanol because it is suited to compression ignition engines, with their superior efficiency, and because DME, unlike methanol, is nontoxic and does not constitute a spill hazard.

China has been promoting DME as a home heating fuel for some time, but not as a transportation fuel. Iran has been running a few experimental buses on DME but otherwise the chemical has been pretty much absent as real contender among alternative fuels. Princeton University has published a number of studies on DME touting its suitability for mass transport, but up until now it has lacked real advocacy. Now that may be changing.