- $20 per Gallon
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- Of Mileage and Markets - the Politics of Fuel Efficiency
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- Structural Nanotubes Now?
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- STATE OF THE INDUSTRY - PART II
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- Maritime Transport in an Energy Constrained Future
- Maritime Transport and Energy - Part II
- The Future of Aviation
Week of August 10
Submitted by Dan Sweeney on Tue, 2008-08-19 20:32.
Two IPOs and a Thermionic Revolution
The news that really caught my eyes this week in the alternative fuels space was an announcement on the part of Changing World Technologies of an impending IPO (initial public stock offering). Big IPOs were characteristic of the dotcoms and the telecom startups back in the late nineties, and a lot of people have been predicting them in the alternative energy sphere. But few have taken place thus far, and this will be the first big one involving a hot alternative fuel startup.
Frankly, I have no very good idea how this is going to play out. Some of the solar companies have done pretty well in the financial markets, but solar is a well established industry compared to alternative fuel. Corn based ethanol has primarily been positioned as a fuel additive not a primary liquid fuel, and biodiesel is having difficulty going forward due to rising commodity prices for oilseed crops. And the so-called second generation biofuels such as cellulosic ethanol, butanol, "green gasoline", and DME are at the earliest stage of commercial development or else pre-commercial, while experimental. alternative fuels based upon unconventional fossil fuels, are, with the exception of fuels from oil sands, pretty insignificant as well.
In short, the alternative fuels industries, which we cover so assiduously and believe in so passionately, are fuels of the future rather than fuels of the present. They are industries of promise and potential, but, unlike the tech plays of the nineties, they are not exploding.
Having said this, I would also state that I'm not surprised that the well publicized Changing World Technologies is making this play. They've been on the cover of "Discover" magazine, and they've got all kinds of other adulatory press coverage. And they've made big promises about making cheap synthetic hydrocarbons out of biomass and/or industrial wastes of various types.
Changing World uses a processing technology variously known as hydro-thermal upgrading or thermal de-polymerization. It is not, contrary to the many breathless accounts in the lay press, anything radically new, and was utilized for producing coal oil in the nineteenth and twentieth centuries and is used today experimentally to produce petroleum analogs from oil shale. Other companies with somewhat similar technologies include Hom-tov in Israel, Blue Ensign in Australia, General Atomics, Syntroleum, and Virent in the U.S., and Royal Dutch Shell in the Netherlands. The old Bergius direct liquefaction process for making gasoline out of a coal slurry is also within this family of techniques.
While the above mentioned techniques, are not identical, they all utilize a fundamentally similar approach. Instead of vaporizing or gasifying the feedstock, as in the more commonly used fast pyrolysis and gasification techniques, these methods heat feedstock but keep it in a supercritical liquid state under high pressure—in other words, there is no partial combustion and no vaporization. Most of them use lots of water, and often a simple hydrocarbon such as tolulene that serves as both a solvent and a hydrogen donor. In some cases gaseous hydrogen will be added as well.
The scientific and engineering papers on these techniques within the public domain, including a book length report from General Atomics, appear to indicate process economics that are somewhat superior to those for gasification despite the fact that these processes are endothermic, that is they require a significant thermal energy input. They do, however, require the use of highly corrosion resistant high pressure reactors which entail high overall capital costs. Their singular advantage is that the end product coming out of the reactor is a useful hydrocarbon requiring little upgrading.
Changing World, which has been mentioned previously in these pages, has been operating a small commercial facility using meat processing wastes, an especially rich feedstock that is not in plentiful supply and could not support massive production of liquid fuels.
Interestingly, Syntroleum, a publicly traded company which has focused on gas-to-liquids and coal-to-liquds in the past, has a joint venture underway with Tyson foods which will use a similar process to convert chicken waste fat into aviation fuel and synthetic diesel. That project, however, will not result in any production until 2010.
W2 Energy Announces an IPO as Well
Since I learned of the Changing World Technologies IPO, I was informed that W2 Energy, another startup would also be doing an IPO. This output has what I would term an enhanced gasification technology where a plasma ignition system known as a gliding arc tornado assists combustion and purportedly achieves superior economics.
I have tried to interview W2 principals in the past, but I've never received a response and so all I know about the company is what is available in print and online. The technology seems promising, and it is applicable to a wide range of feedstocks including municipal solid waste, biomass, low grade coal, and even peat. The question is who will license it and how will they fare in the marketplace. That will ultimately determine where the stock goes and how the owners of the stock options ultimately fare.
A Thermionic Revolution
My next item concerns an Australian inventor named Philip Hardcastle, who among other things, invented the pause function on the VCR, for which all of us will forever be grateful.
Now Mr. Hardcastle has announced an innovation of potentially somewhat greater import, if his claims are even approximately correct.
The device is a species of thermionic electrical generator, but so different from any I have encountered, I have had difficulty assessing its potential. I have a sufficient background in electronics and electricity to understand the principles of operation, but I cannot determine if the device will perform as advertised based upon the brief technical paper written by the author.
So here's the skinny, and I hope I'm accurate in my description.
Conventional thermionic generators produce an electrical current in the presence of a heat differential. A good example is the cathode or negative element in an old fashioned power vacuum tube of the sort still used in electric guitar amplifiers. The cathode consists of a metallic filament which is resistively heated either by an adjacent heating grid or by the direct application of electrical current. When the cathode is white hot, electrons literally boil off its surface and form a space charge around it. Conversely, electrons accumulate on an opposing positive element known as an anode. The space charge is modulated by another element called the grid which causes changes in voltage on the anode which in turn engenders current fluctuations in the output circuit.
This sort of thermionic circuit is massively inefficient, producing large amounts of waste heat. Relatively little of the thermal energy is converted into electrical energy. A related energy conversion device known as thermo-electric generator is just about as bad.
Generally, when you're looking at thermal energy to electrical energy converters, you're facing single digit conversion efficiencies. They're just not very practical.
Hardcastle claims better than 95% efficiency. That's highly significant. Even thirty percent efficiency would open up vast and lucrative markets provided the device could be inexpensively mass produced.
So how does this doohickey work?
The basic device is simplicity itself. It consists of a metallic ring or hoop with a very small gap. Rather curiously, the outer surface of the hoop is covered with a dense array of fine filaments—spines, if you will. These constitute an array of cathodes or negative electrical elements.
They receive their negative charge not by being brought to a white heat to the point where electrons boil off, but by an entirely different means. Hardcastle, by his own account, dug up some old scientific papers published in the teens of the last century in which experimenters reported that spinning metal hoops would accumulate negative electrical charges at the periphery when free electrons were flung into space by centrifugal force—which, as we all know, is not a primary force at all, but simply a form of acceleration.
The experimental hoops never accumulated charges of high potential, and Hardcastle indicates that rotational velocity necessary to achieve that goal would cause the hoop to fly apart. The filaments, however, by presenting narrowing pathways to electron flow would accumulate very high potentials at their tips and would thus allow the discharge of a very large number of electrons and the formation of a considerable space charge. That's the theory.
The hoop itself would take the form of a high velocity flywheel and would spin in a hard vacuum upon a frictionless magnetic, bearing and would be accelerated by means of inductive coupling or by a drive shaft. In the near absence of friction it would spin indefinitely once set in motion. The electrons leaving the surface of the hoop could be presumed to exhibit some slight tidal friction, but so negligible is their mass, that it would not be significant.
The electrons are ultimately returned to the inner surface of the hoop, the anode, if you will, to close the circuit. As they strike the inner surface, they generate heat and the hoop's temperature rises. Which intensifies the release of free electrons from the outer surface.
In this basic configuration the electrons in the system are performing no work beyond heating the hoop, and the system as such is merely the extension of a nearly century old experiment published in a forgotten journal. In other words, Hardcastle's first embellishment is not in itself very significant.
Hardcastle claims that the secret to making the device perform useful work is to make the hoop a homopolar motor, also known as a Faraday motor. While Hardcastle neglects to mention this in his paper, the hoop would have to be magnetized in order to function in this manner. The radial motion of electrons going through the hoop and out into the surrounding vacuum would generate a magnetic field that would react with field of the permanent magnet that is the hoop itself, and these counter forces would generate torque in the hoop causing it to spin faster.
Now here's where it really gets interesting. Hardcastle proposes to connect the spinning hoop to an external motor/generator via a driveshaft and use the homopolar motor, that is, the spinning hoop, to generate electricity by turning the generator.
The hoop loses both thermal, electrical, and ultimately mechanical energy to the generator, and, absent any external energy inputs, should decelerate and cool. But Hardcastle claims that if an external heat source communicates with the inner surface of the hoop, the velocity will be maintained. Heat will be efficiently converted into electricity though in a roundabout manner.
In principle it should work, but will it be close to 100% efficient? Hardcastle claims it will be because the effective work function of the outer surface of the hoop will be extremely low, the desideratum for any thermionic generator.
Work function refers to the susceptibility of a material to the thermionic or thermo-electric effects. That is, how easily does the substance give up electrons in the presence of heat? The lower the work function the better, but no known material has a low enough work function to provide good conversion efficiency. And, worse yet, the materials with the highest work functions also have the highest thermal conductivity, namely metals. They simply can't maintain the temperature differential to produce pronounced thermo-electric effects.
Tremendous amounts of money have been spent researching various exotic compounds known as "rattling lattices"—crystalline structures that are thermally resistive but have relatively low work functions. So far no one has identified a compound that is ideal, however.
Hardcaste's totally off-the-wall approach appeals to me on a certain level, but I've never read anything specific about the work function of rotating discs or hoops. One should be able to extrapolate from those ninety year old experiments, but it's probably better to repeat them.
So what's it all mean? And particularly what's it all mean for the alternative fuels business?
If his claims are true, and if Hardcastle can put together an effective company himself or sell the intellectual property to someone else who can, it could be fairly momentous. There are all sorts of sources of thermal power waiting to be tapped, and Hardcastle claims that by means of his device, which he calls a "rotating thermionic generator", appreciable amounts of electrical power can be generated with fairly low grade heat including the ambient air temperature. If that's true, one would expect such a device to make inroads into the markets for solar energy, and ultimately the small generator market based upon the burning of liquid fuels.
Here I would hasten to add that in the past two companies, ENECO and Cool Chips advanced similar claims of having developed ultra-efficient thermo-electric devices. Neither company has made any sales to date, though both have managed to attract lots of investment dollars.