Hydrogen as a Fuel for Automobiles and Other Vehicles

On first glance, Hydrogen seems to be the ideal fuel for automobiles and other vehicles. It doesn't seem like one could get any cleaner burning, since hydrogen burns (oxidizes) to form simply water vapor. Nothing else! No pollution! What a seemingly incredible advancement over our current internal combustion engines that put thousands of tons of pollutants into the Earth's atmosphere, and many other environmental problems. Did you know that EVERY gallon of gasoline you burn up sends around 18 pounds of carbon dioxide into the atmosphere?^{note 1}

Hydrogen (H₂) plus Oxygen (O) makes H₂O, water, or actually, water vapor, at higher temperatures. And Hydrogen is actually capable of NEARLY meeting those high expectations.

And there is even a concept, and somewhat of a device, called a Fuel Cell (originally conceptualized in the 1830s), which can use this chemical reaction to generate electricity. During the 1960s, NASA developed Fuel Cells which produced electricity for spacecraft. They worked reliably and fine, but they were horrendously expensive. There have been people trying to make inexpensive versions ever since! In the early 1990s, some breakthroughs were found. The concept of a Fuel Cell is actually pretty simple. You provide a supply of hydrogen gas and oxygen gas (which is usually from the air) which are separate, with a unique barrier between them. The simplest version of a Fuel Cell is to allow the NUCLEUS of the hydrogen atom to pass through the barrier while not allowing the electron to also pass through. The electron is then caused to follow some DIFFERENT path to eventually get to where the nucleus had gone to, where the end result will be water molecules. The electrons are negatively charged, and when they are forced to follow that alternate path, they are MOVING CHARGES which is the same as an electric current. In words, it therefore seems quite simple to have a Fuel Cell produce electricity. However, in practical terms, there are lots of complications! It may still be ten or twenty years before any reliable technology will exist which has tolerable cost.

And WHY is a Fuel Cell such an attractive thing? Why not simply try to BURN the Hydrogen in a conventional engine? There are actually two major reasons. The central one is that modern internal combustion engines only have an overall efficiency of around 21% (up from around 15% in the 1970s), while the fuel cell process has the THEORETICAL CAPABILITY of being nearly 100% efficient (although existing ones are generally around 40% efficient). The second reason is that Fuel Cells provide a CONTROLLED OUTPUT of power. In an internal combustion engine, the oxidation of Hydrogen can and does occur in two VERY different ways! The desired on is by combustion (technically, conflagration), where the laminar flame front speed is around 8 feet per second at standard temperature and pressure. The undesired one is by explosion (technically, detonation), where the flame speed is over 9,000 feet per second, many times the speed of sound and incredibly dangerous! You might notice that NO experts really ever talk about using Hydrogen as an actual FUEL for existing engines (although there are many less educated people who talk about that a lot!) These are the reasons for that! (A few experimental vehicles HAVE been built to burn Hydrogen in a modified internal combustion engine, but they have not really impressed anyone.)

But Hydrogen itself has an ENORMOUS disadvantage, as well as many smaller ones. It cannot really be considered a "fuel" at all! Yes, it IS, but it isn't! It IS because of the exothermic chemical reaction described here. It ISN'T, because it does not occur naturally. We have such an attachment to petroleum and natural gas and coal and uranium BECAUSE they exist naturally. We actually have the technology to manufacture petroleum, but it would be so involved and expensive to do that it would never be worth it. Hydrogen is very different. It is so chemically reactive that it IMMEDIATELY combines with nearly any other atom (ion, actually) that happens to be near it. So there is NO natural supply of Hydrogen, anywhere on Earth. There cannot be!

This really changes the equation A LOT! Essentially, Hydrogen should be considered to be similar to a battery, where electricity is produced somewhere else and then STORED in it. And it turns out that the chemical properties of Hydrogen are such that it is rather difficult to pull hydrogen atoms out of any of the molecules that it exists in. That means that a lot of power is needed to separate out the hydrogen. In a sense, that is a reason why it is attractive! If a LOT of energy is needed to separate it out, then the SAME LOT OF ENERGY will get released when it is able to recombine. (The Conservation of Energy is involved here.)

It turns out that there are ways that methane gas can be combined with very high temperature steam, with a special catalyst, where Hydrogen is produced. THAT is the process by which around 95% of American Industrial Hydrogen is produced. Unfortunately, it not only uses the fossil fuel methane as chemical stock material, but the process required very high temperatures, which uses up even more fossil fuels. For each pound of Hydrogen produced from methane, over 9 pounds of carbon dioxide is created and released into the atmosphere. Since around two pounds of Hydrogen gas is needed to equal the energy in a gallon of gasoline, this means that the process for creating Hydrogen from methane gas produces roughly the SAME amount of Global Warming carbon dioxide as did the gallon of gasoline being replaced! That is NOT Green!

One obvious primary source of Hydrogen is water. That process does NOT give off any carbon dioxide. However, it requires really large amounts of electricity to drive the process, and the creation of that electricity in a distant powerplant (usually by burning coal) gives off a lot of carbon dioxide as well. These concepts that are allegedly so Green, really are not!

Here is part of a paragraph from the Grolier Encyclopedia:

Electrolysis is an energy-consuming process. To obtain 2 grams of hydrogen and 16 grams of oxygen by the electrolysis of 18 grams of water, the equivalent of 68,300 calories of electrical energy must be supplied. This same quantity of energy, however, can then be recovered from the hydrogen and oxygen, either suddenly in an explosion or slowly if they are brought together in a FUEL CELL.

Two grams of Hydrogen is only 1/227 pound, so the electrical energy actually required to produce a pound of Hydrogen is therefore 68,300 * 227 or 15,500,000 calories of electrical energy! This can be converted into 18,000 watt-hours or 18 kWh. As noted below, the existing technologies to create Hydrogen by electrolysis are all around 20% efficient, which means that around 100 kWh of electricity is used up to produce a single pound of Hydrogen gas. If a house's current 15-cent per kilowatt of electricity is used, that therefore would require at least $15 of house electricity to be used up to create that single pound of hydrogen gas! We will see below that one pound of hydrogen gas contains just under half of the chemical energy of a single gallon of gasoline, so, even if everything else was perfect, more than $30 of modern house electricity would be required to simply PRODUCE an equivalent amount of Hydrogen gas to one gallon of gasoline! And then that gas would have to be ferociously compressed and all the rest.

Down below, we will see that the lowest quality of Industrial Hydrogen was sold for around $42 per K-tank (per pound) in 2003, which actually represents a fairly attractive pricing! (Note that meant that in 2003, the two pounds of Hydrogen necessary to have the same amount of chemical energy (126,000 Btus) as one gallon of gasoline would have cost around $85!) In 2006, the price was still about the same for a K-tank of compressed Hydrogen. This price is in a DELIVERED form, of standard high-pressure tanks, called K-size tanks, which is how one can buy one pound of Hydrogen gas at a time. However, in really large quantity, such as full (very high pressure) tanker truckloads, the recent price publicized is generally around $3 to $5 per CCF (hundred cubic feet) of Hydrogen, but that price is FOB, meaning that the cost of freight shipment in such a truck is added on. The point here is that there is an extremely wide range of possible costs for Hydrogen gas! Proponents of Hydrogen always cite the $3 to $5 per CCF, which means $6 to $10 per pound of compressed Hydrogen gas, or $12 to $20 for enough Hydrogen gas to contain the equal energy as one gallon of gasoline. But after the freight is added, and then the handling and storage charges of a local industrial warehouse, even under these BEST conditions, the final price of the Hydrogen to the customer seems certain to be at least $40 (for enough Hydrogen to equal the energy in one gallon of gasoline.) The promoters and salespeople never seem to mention this, but even if relatively few middlemen try to profit from handling the Hydrogen, it is hard to see why many vehicle owners would be willing to pay $40 or $85 to buy enough Hydrogen to replace a single gallon of gasoline.

And even these prices do not actually include all the final costs to a vehicle owner. K-size industrial tanks are NOT owned by the user, but instead RENTED, such that the tank owner can do the regular required testing to ensure that the tank has not deteriorated to a point of not being safe. It figures that the US government would require MASSIVE testing of any 3,000 PSI tanks which are inside of vehicles on public highways!

In any case, we KNOW that you CAN get compressed Hydrogen locally from an Industrial Gas supplier, at roughly that $42 per full K-tank (which is one pound of Hydrogen gas at 3,000 PSI pressure). Should it turn out that you can obtain highly compressed Hydrogen gas at lower cost, it seems unlikely that you will ever get the full taker truckload price, but you would be free to try to find the best price you can. This presentation is simply describing known facts. This presentation will continue with the KNOWN price which you are likely to be able to buy compressed Hydrogen gas for, the $42 per K-tank (which is produced from the fossil fuel methane gas).

Because of the problems of storage and transport of Hydrogen gas, around 95% of the Hydrogen that is currently produced, is USED right at that same location! Most of the remaining 5% is compressed or liquified down to near absolute zero, for transport to use at other locations. Much of the glowing reports that keep getting into the news are SPECULATIONS regarding future hopes, rather than any actual reality!

As with nearly all other subjects on the Internet, there are plenty of web-sites that present information which might APPEAR to be extremely attractive! One even claims to provide a GALLON of compressed hydrogen for less than a gallon of gasoline costs! Quite amusing. I wonder what their price is for "a gallon of dynamite" or "a gallon of Uranium"! But they are counting on the public to not be able to know that a GALLON of a COMPRESSED GAS is a meaningless concept! And they seem to also overlook the FACT that it requires a K-tank weighing close to 100 pounds to provide the necessary strength to contain even ONE POUND of Hydrogen gas compressed to 200 atmospheres (3,000 PSI)! A GALLON indeed! Such statements are only made by people who are ignorant of the actual scientific facts! The sad thing is that there are a LOT of people who will read their stuff and believe that they actually know what they are talking about, and will give them money so that they could "improve" their products! It is too bad that the word SCAM cannot automatically appear in such web-sites!

Peak Power Rating vs. Average Power Rating You may drive a car which was advertised as having a 495 horsepower engine, and that may have even affected whether you bought that specific car. That engine rating can be called a PEAK POWER RATING, being the greatest amount of power that it is capable of producing. When creating that enormous amount of power, it is realistic to expect to get around one or two MPG gas mileage. But for AVERAGE driving on an Interstate Highway, your engine only produces around 40 horsepower, during which you may get 25 miles per gallon gas mileage. This AVERAGE situation is a far more accurate description of what YOU CAN ACTUALLY EXPECT, such as regarding gas mileage. Both situations are true, but they are extremely different. One is a situation which sounds very impressive, but which you will likely NEVER actually experience, except possibly rarely for a second or two at a stoplight! The other is a situation which you may experience every day of driving! IF you were only given ONE of the numbers, which would you consider more important to know? Whenever electricity ratings are given for alternative energy devices, they seem to always be PEAK POWER RATINGS, meaning the greatest amount of electricity or power which can be created. That is entirely different than ratings for AVERAGE USAGE CONDITIONS, which would be realistic numbers of amounts of electricity or power which might NORMALLY be expected to be provided. The discussion and calculations included here will indicate that OFTEN the realistically expectable amounts of electricity or power is only around ONE-TENTH that of the PEAK POWER RATINGS. But no one bothers to mention this important fact! So advertising makes claims of spectacular performance numbers for photovoltaic solar-electric panels, and for solar roof panels, and for electric vehicles, and for Hybrid vehicles, and for windmill-electricity-generation, and even for FUTURE giant windmills and hydrogen as a fuel. They invariably state PEAK POWER RATINGS, like that 495 horsepower engine in the car, numbers that may be technically true but are extremely misleading.

You can look up something called the Electrochemical Equivalent of Hydrogen in many Reference books. It is the amount of electrical energy that exists in the chemical bonding of Hydrogen atoms inside of the molecules it exists in, such as water, H₂O. Those Reference books show that 12,062.183 ampere-hours of electrical energy is required to release a single pound of Hydrogen from any chemical compound. This is a LOT of energy! It turns out that there are no "perfect" devices to do this, and the best tend to be around 20% efficient at getting the Hydrogen released, regarding the electricity used. So we actually need to use up around 60,000 ampere-hours of electrical energy in order to get one pound of Hydrogen released (and therefore available as a fuel). That is a LOT of electricity! Your kitchen toaster uses around 15 amps of electricity, for maybe 30 seconds. Here, we are talking about 100 amperes of electricity being used continuously for 600 hours or 25 days!

So, proponents of "the coming Hydrogen economy" brag about the fact that Hydrogen CAN be produced by electrolyzing water to separate it into Hydrogen and Oxygen gases. Then they brag about the fact that when Hydrogen burns, it combines with Oxygen to create "lots of power, and just water vapor". Those statements are totally true, and nearly everyone seems to totally trust the people pushing Hydrogen and Fuel Cells, without asking the next, VERY IMPORTANT, question! Didn't the First Law of Thermodynamics prove to us that we cannot have energy simply appear? That there is a Conservation of Energy? So, if we have to SEPARATE the Hydrogen from the water to start with, doesn't it seem obvious that it has to require AT LEAST AS MUCH energy as will later be released when the Hydrogen again winds up as part of water? How come nobody asks this really obvious question???

In fact, there is another closely related Law of Nature, regarding something called Entropy, where NO actual process can be 100% efficient. So, as discussed below, to provide all that electricity needed to release Hydrogen from any chemical compound: (1) coal must first get burned in a power plant; (2) it must heat water into steam; (3) that steam must drive high speed turbines; (4) the turbines must drive alternators; (5) the electricity must then travel through wires and transformers to get to your house; (6) an electrolysis apparatus must use (a LOT of) electricity to produce Hydrogen gas; (7) that gas must be tremendously compressed to be of manageable size; (8) THEN you finally get to the Fuel Cell technologies that are still being developed!

The result of this is that Hydrogen power for vehicles might SOUND amazingly Green, but the reality is that the power consumed (at that distant electric power plant that you never see) to create the Hydrogen is at least six times the amount of power associated with a gallon of gasoline! This results in that distant electric power plant burning around six times as much coal and converting it into carbon dioxide as when a vehicle simply burned gasoline in its engine! (Linked web-pages to this one give the specifics where a gallon of gasoline burned in a vehicle produces around 18.3 pounds of carbon dioxide which gets released into the atmosphere. Due to those steps enumerated above, around 37 pounds of coal must be burned in an electric power plant, which releases around 108 pounds of carbon dioxide, to produce enough electricity to provide enough electric power to match the performance of one gallon of gasoline. Currently, producing Hydrogen is even worse than this, because current technlolgies to decompose water are nowhere near being efficient! So at the very BEST, these supposedly GREEN technologies cause AT LEAST SIX TIMES AS MUCH carbon dioxide to be released (at that distant power plant) than if the original gallon of gasoline was burned as always!

For now, no one seems willing to tell the public these things, because they REALLY want to get the public to eventually buy a zillion Hydrogen powered vehicles! This exact same situation occurred some years back (in the 1980s and 1990s) when Battery-powered vehicles were supposed to be the FUTURE! Battery power is GREAT, IF you only consider the vehicle itself. It gives off ZERO pollution! But these same issues regarding the massive amount of electricity needed to re-charge those batteries (even for golf carts) already costs about as much as what the equivalent amount of gasoline would have cost! And at the distant power plant where that electricity was produced, a LOT of pollution, MANY TIMES MORE, carbon dioxide and atmospheric heat was created and released. You just don't see it! Ditto, with Hydrogen!

It seems fascinating that two technologies that are promoted as GREEN, are each horrendous when the whole picture is examined, because that distant power plant has to burn ferocious amounts of coal to produce that much electricity! And the many people who optimistically think that they will be able to use a few solar panels or a small windmill to produce a hundred amperes of electricity for 25 constant days to generate one pound of Hydrogen? I have a Brooklyn Bridge that I think you may want to buy!

Faraday

There is a more technical name for this relationship. It is called the Electrochemical Equivalent. For hydrogen, one can look up that value in many reference books, as being 12,062.183 ampere-hours per pound. One can easily see that at a rate of ten amps, the 1206 hours is slightly over 50 days, as noted just above. With actual existing equipment, around 250 days of continuous use and consumption of a lot of electricity, just to produce that one pound of Hydrogen.

People who promote hydrogen seem to imply that by simply snapping one's fingers, all sorts of hydrogen can be obtained! Note that many of these comments and calculations just above had assumed that all equipment was perfectly efficient, which is never even close to being true in real life. YES, they are technically correct that you could take a glass of water from your kitchen tap and generate hydrogen gas from it by electrolysis, which might then be used as fuel in a vehicle. But see that they have sort of left a LOT of important details out?

In principle, they could also have said that that same glass of water could provide most of the power needed by the entire United States if it was processed in a Fusion Reactor (the way the Sun operates, but which appears to be far beyond anything we can build). Such statements are technically true, but incredibly misleading because of the many practical matters which were not mentioned!

Environmental Impact

In addition to NO_x production, if the device in which the burning occurs has any lubricants, like oil, there are also oxidation products of the Carbon in them, which can contain CO, carbon monoxide. When Hydrogen is burned in a decently designed (laboratory) device, these environmental problems are fairly minor and they are rarely considered to be any great danger.

I said laboratory here because the great difficulty and expense of generating significant amounts of hydrogen seems to have limited such experiments to laboratories so far. I am not aware of any actual products that use Hydrogen as the primary energy source, and it seems unlikely that any will exist until Fuel Cells are fully refined.

Logistics

However, a pound of gaseous Hydrogen is HUGE! At standard atmospheric pressure and temperature, it takes up around 190 cubic feet of space. In contrast, that pound of gasoline only takes up about 1/45 of a cubic foot. Hydrogen gas takes up around 9,000 times the space that the same weight of gasoline does!

For the record, we are NOT suggesting that gasoline is any great fuel source. It IS convenient, and compact, true. But it causes pollution of many sorts, including adding large amounts of carbon dioxide to the atmosphere which directly contributes to global warming. So this is NOT a fan letter for gasoline! It is instead intended to present an accurate scientific discussion of Hydrogen as a fuel, where all the press reports we hear in the news seem to always leave some really important stuff out!

Consider a mid-sized car, traveling at 60 mph down an Interstate Highway. It is well known (and easy to calculate) that roughly 40 actual horsepower is needed to maintain a constant speed. A horsepower is equal to 2544 Btu/hr, so we are talking about 102,000 Btu/hr of "actual" energy/work. For an hour's driving, we would therefore need 102,000 Btu of output energy, to ACTUALLY MOVE THE CAR THROUGH THE AIR AND WITH TIRE RESISTANCE. (A gasoline engine would use maybe 3 gallons of gasoline during that hour's driving [20 miles/gallon] which actually contained about 378,000 Btu of energy, but the engine/car efficiency is only roughly 25% to create the 102,000 Btu of output work.)

Consider now that a cubic foot of Hydrogen (not compressed) only contains 319 Btu per cubic foot. That hour of driving would therefore require (102,000 / 319) over 300 cubic feet of the Hydrogen! Notice that this does NOT refer at all to any engine or drive system, and is instead simply considering the Aerodynamic Drag of the vehicle pushing its way through the air at 60 mph and the Tire Resistance Drag due to the tire sidewalls flexing each time the tires rotate. The ACTUAL efficiency of existing vehicles being around 21% means that IF Hydrogen was burned as fuel in a vehicle, we would need to duplicate that actual 378,000 Btu of source chemical energy, and we would therefore need to use up (378,000 / 319) around 1200 cubic feet of Hydrogen for that hour trip. In case you are curious, a 10 foot by 15 foot living room, with an 8-foot ceiling, contains around 1200 cubic feet. THAT much Hydrogen would be necessary to be consumed for that single hour of driving!

We can say this same thing in terms of "gallons". A gallon of gasoline contains around 6 pounds, and has 126,000 Btus of energy in it. A "gallon" of hydrogen (gas) only contains around 40 Btus in it. Quite a difference! Instead of a two cubic foot gasoline tank (15 gallons) in your car, you would need a tank more than 3,000 times bigger, over 6,000 cubic feet, for the equivalent Hydrogen! That's a little more than TWO standard semi trailers (8'wide x 8'high x 45' long or 2900 cubic feet each). Pretty big gas tank!

Well, that is obviously not going to happen! So, the many ongoing explorations into using Hydrogen as a fuel always involve carrying HIGHLY COMPRESSED Hydrogen in very thick, heavy tanks. If you have ever seen the kinds of tanks used for the Oxygen for a worker's oxyacetylene cutting torch, that's the kind. Such tanks can hold Hydrogen at around 200 times atmospheric pressure, or 3,000 PSI, an extremely high pressure. When Industrial Hydrogen is purchased, it is bought in tanks like that.

Well, at 3,000 PSI, or 200 times atmospheric pressure, the Ideal Gas Law tells us that the Hydrogen (equivalent to a 15 gallon gasoline tank) would now only take up 6000/200 or 30 cubic feet. That works out to around 30 of those (fairly large) high pressure storage tanks (again, to match the effective capacity of the 15 gallon gasoline tank.) Each of those tanks (called K tanks) actually contain a maximum of about one pound of Hydrogen gas. Each tank is very massive to withstand the extremely high pressure, and each weighs nearly 100 pounds empty. (And around 1 pound more when filled with Hydrogen!) So the normal American car which presently weighs around 2800 pounds would have to have around an extra 3,000 pounds of those 30 high-pressure tanks added, so the vehicle would now weigh more than twice as much as current cars! (This tremendously affects acceleration, handling and other performance, and it would be like that car forever pulling a huge 3,000 pound trailer behind it.

Safety Considerations

Those 30 very high pressure tanks present another complication. If industrial workers ignore proper safety rules when working with a high pressure Oxygen tank (at 1500 PSI pressure), it could fall over. As the hundred-pound tank falls over, it quickly develops a lot of momentum. If there should happen to be something in the way on the floor, where the neck and valve of the tank hit it, the neck and/or valve has been found to tend to just snap off. Suddenly, 1500 PSI of compressed gas has an easy way out, and it all goes out almost immediately. Isaac Newton told us about the Law of Action and equal Reaction. The hundred pound body of the tank then zooms off like a rocket at extremely high speed in the other direction. There have been many industrial accidents where such Oxygen tanks flew many hundreds of feet through the air and passed completely through concrete walls!

Most suppliers of compressed industrial gases display photographs of vehicles where ONE such compressed gas tank had not been strapped down properly and the neck wound up snapping off. Usually, the vehicles shown in those pictures are hard to tell as being vehicles, except for maybe a tire somewhere in the picture. The results of that carcass of a hundred-pound oxygen tank zooming off like a rocket pretty much passes through whatever had been in its way. If the vehicle had been traveling at highway speed, it suddenly no longer has enough parts to continue as a vehicle!

Get the point? Imagine having 30 such tanks in a car. If even ONE vibrates loose from its clamps, or the guy who last replaced them didn't strap them all down properly, or an accident occurs where you hit another vehicle or a tree? If even one of those tanks ruptures, REALLY bad things would result. Given that Hydrogen tanks contain TWICE the pressure of Oxygen tanks, the effects of a tank neck snapping off is both more likely and also potentially more destructive. And have you ever even seen what happens to any NORMAL car when a semi hits it? Imagine if that target car had 30 tanks inside it which each were simply waiting to become unguided missiles!

Notice that this issue is not actually related to any hazard of Hydrogen itself, but rather the fact that it would have to be stored at extremely high pressures due to its very low density. Whether it was a high-pressure Oxygen tank or an even higher-pressure Hydrogen tank, this danger is virtually the same, and is entirely due to the pressure that the gas is compressed to.

Because of this extraordinary safety hazard, which is only due to the very high pressures involved and really has nothing to do with the Hydrogen itself, there is no imaginable way that the US Government would ever allow such vehicles to be generally licensed. It would conceivably be a lot safer to drive a dynamite truck!

Cost Considerations

Such equipment is difficult enough to operate when the gas being compressed is Nitrogen or Oxygen or Carbon Dioxide. But when it is also a potentially explosive gas such as Hydrogen, safety issues multiply. Imagine having the necessary compressor and pipes and tanks in a garage, and a tiny leak appears in one of the pipes. A spark or someone with a cigarette? Poof, no garage! Ever seen the Hindenburg disaster movie?

However, even if there was some way to do all that compression, it takes a good amount of electricity for the compressor motor to drive the compressor. A significant cost would be involved for that compression, even if you somehow had your own compressor.

In addition, free Hydrogen does not exist. All of the Hydrogen that might be collected is now in various compounds. The simplest to deal with is water. If you had Chemistry in High School, then you hooked up some electricity to an apparatus that contained water, and you saw little bubbles of Hydrogen form in one upside down test tube and Oxygen form in the other. That is called Electrolysis, or the Dissociation of water. It is obviously pretty easy to do.

But those are just little bubbles of Hydrogen that you collect. After a minute or two of such an experiment, you had a half-finger-sized bubble of Hydrogen gas in a test tube. A spark or flame, and POP, it exploded! And everyone laughed! But remember now that you are going to need an amount of Hydrogen that would more than completely fill two semi trailers, to just equal one tank of gasoline! It is possible to calculate the amount of electricity needed for that, but you must get the idea that it is a LOT of electricity! (We discussed some of that up above) So, you get to pay your electric company for that, too.

So, you would wind up paying for the electricity to Dissociate the water in the first place, plus the cost of the electricity needed for the extreme compression. Of course, all of this would be after you bought the necessary equipment! We discussed above that this will increase your electric bill by at least $30 (and likely much more) for the equivalent of one gallon of gasoline. Also, roughly 36 pounds of coal have to be burned at a distant electric power plant to produce that same energy that a single gallon of gasoline contains. Which causes roughly SIX TIMES the amount of global warming carbon dioxide (107 pounds) to be produced at that power plant than if you had simply kept driving the gasoline powered vehicle (18 pounds)! (See the Battery-powered vehicle presentation linked at the bottom of this page for the complete details on that.)

An alternative, of course, would be to buy (rent actually) tanks of industrial Hydrogen that is already compressed. Current prices (2003) for Industrial Hydrogen (the lowest purity available) are around $42 for a standard K cylinder, a very high pressure tank which contains 197 standard cubic feet of Hydrogen, plus a monthly rental fee for the tank. The 6,000 cubic feet that we had earlier determined were equal to one 15 gallon tank of gasoline, would therefore be around 30 of these tanks, which would cost around $1260 for (one gasoline tankfull!) the compressed Hydrogen PLUS the monthly rental of at least $300 for the tanks themselves. (Using the single gallon of gasoline scale we discussed above, you would need to buy/rent only two K-sized tanks, for around $85 plus cylinder rental costs, for the equivalent to that single gallon of gasoline.)

We complain today at paying $3 per gallon for gasoline, which would be $45 for our 15 gallon tank. How many people would be willing to pay $1260 and more for the same driving distance, using bought Hydrogen?

Flame Speed

(NOTE: There does not appear to be available any data regarding flame-front speed for Hydrogen gas when compressed as in a car engine. Therefore, we add the following discussion, which also shows the sort of far more comprehensive Physics research that is the basis for essentially all the statements made in this presentation.)

First, everyone is taught in school that Hydrogen "simply" combines with Oxygen in the familiar (2) H2 + O2 ↔ (2) H2O. That turns out to be an enormous simplification! There are actually 19 different reactions that can and do happen! Each releases different amounts of energy (with two of them even REQUIRING energy to occur!). In general, two or more of these reactions occur in rapid succession, with the end result of the familiar reaction. Physicists and Chemists analyze ALL of those 19 unique reactions, in order to better understand exactly what is going on and why. In fact, the overall reaction of Hydrogen with Oxygen can occur in two VERY different ways! The DESIRED one is by burning (conflagration) which has the flame-front speed indicated, around 8 feet/second in the atmosphere. The UNDESIRED one is by explosion (detonation) which has a flame-front speed of 2,821 meters/second or 9,255 feet/second! That is around EIGHT TIMES the speed of sound and many times faster than the fastest rifle bullet travels! It is incredibly dangerous when Hydrogen decides to detonate, and science does not yet have a very complete understanding of why it sometimes does! Our discussion will be about the DESIRED laminar flame-front process. Next, the velocity of the (laminar) flame-front is known to be very dependent on many different variables. Here is an equation that gives the flame-front velocity (speed): (There are actually three different theories which exist to explain the motion of flame-front travel and this equation happens to be from the one that seems to be the best. Many of the equations involved are far more complex than this one. They were generally developed during the 1980s.) If a number of reasonable assumptions are made, this can be greatly simplified into: The exponents are different for each type of fuel gas, and for Hydrogen they have been experimentally determined (Milton and Keck 1984) to be a is 1.26 and b is 0.26 Note that all of this is based on ideal conditions; the perfect proportion of fuel and oxygen; perfect mixing; etc, and that real conditions are often not ideal. If we assume that an engine has an (actual) compression ratio of 8:1, the pressure increase factor therefore would be 80.26 which is 1.717. The natural flame-front speed of 8 feet/second would therefore increase to 8 * 1.717 or 13.7 feet/second. We note that some 2004 research in Bergen, Norway shows a maximum atmospheric flame-front speed for Hydrogen as 2.8 meters/second, which is slightly higher than the 8 ft/sec cited above at 9.2 ft/second. This is still far slower than the measured flame-front speeds inside gasoline-fired internal combustion engines (which is generally at least 90 feet/second during most driving). However, the dependence on temperature causes some improvement in this situation. Hydrogen burns at 2,755°C or 4,991°F. The heating of the gas occurs gradually during the process of the combustion, but if we assumed that the hydrogen got up to that temperature, the temperature dependence factor in the equation above would be around 18 to one. This implies that the COMBINATION of the higher pressure and the higher temperature MIGHT cause a flame-front speed which is comparable to that known to be in gasoline-fired internal combustion engines. But it does not appear that anyone has yet actually done such experiments to validate that statement.

Consider the inside of an engine cylinder in a normal car engine traveling down the highway. The engine may be rotating at 2,000 rpm, or 33 revolutions per second. The piston must therefore move upward and downward 33 times every second, and its (maximum) speed in the middle of its stroke is around 45 feet/second. If a fuel burning in the cylinder is to actually push down on the piston, in order to do actual work in propelling the vehicle, the fuel-air mixture needs to burn at a speed FASTER than the piston is moving! Otherwise, the slow-burning mixture would actually act to SLOW DOWN the piston! It would not only not do productive work, but it would require work FROM the piston.

The ACTUAL flame-front speed inside an ICE might be sufficient for conventional burning as in current ICE engines, but someone needs to do the experiments to confirm that! But it suggests that yet another hurdle might lie in front of Hydrogen ever becoming a common motor fuel.

By the way, the INTENDED usage of Hydrogen in vehicles is quite different from this! The much-publicized Fuel Cell is a device which converts the energy in a fuel like Hydrogen DIRECTLY INTO ELECTRICITY. The premise for future vehicles is that they might use Fuel Cells to provide electricity for electric motor drive systems. Which means that Mortuary Services will soon be appropriate for the Internal Combustion Engine! But it may be another ten or twenty years before fuel-cell technology has developed to the point of that becoming realistic.

As an additional note here, when you see impressive demos on TV or in a video regarding Hydrogen being used as a fuel for a vehicle, try to check to see the source of that Hydrogen! In general, such demos use LIQUID Hydrogen (which is necessarily refrigerated to incredibly cold temperature, within a few degrees of Absolute Zero!) LIQUID Hydrogen does not have the problem of the huge volume of Hydrogen as a gas (where one pound takes up around 200 cubic feet) (one pound of liquid hydrogen takes up less than 1/4 cubic foot, almost 1,000 times smaller). Where we have discussed that one cubic foot of Hydrogen gas only contains around 360 Btus of chemical energy, one cubic foot of Liquid Hydrogen contains around 300,000 Btus of chemical energy in it, relatively comparable to the energy concentration of gasoline (about half of it). So, for demonstration purposes, a fairly small amount of LIQUID Hydrogen contains spectacular amounts of energy in it! Which then gives impressive performance by the demo vehicle. However, IF they used LIQUID Hydrogen, that (small) amount for the demo quite possibly cost them tens of thousands of dollars to buy!

OK. Finally, there are all kinds of hucksters who are trying to sell all manner of products that they claim will give you tremendous improvements in the gas mileage of your vehicle by somehow injecting Hydrogen into the engine. This is really sad regarding how deceptive their presentations are. Again, if you would inject LIQUID hydrogen into any engine, you COULD add a large amount of additional CHEMICAL ENERGY into the engine to be burned. However, what they try to sell are tiny devices which they claim are hydrogen generators. You should realize from this presentation that even if you could generate a cubic foot of hydrogen each minute (which is extremely difficult to do AND would require many horsepower from the engine to generate the needed electricity to do it), that would only be adding around 360 Btus of chemical energy in the hydrogen into the engine (where a gallon of gasoline contains 126,000 Btus of chemical energy in it). A demo where LIQUID hydrogen was injected COULD show measurable improvement, but any device that tries to generate GASEOUS hydrogen to be injected is simply an expensive joke!

Scale of the Need

Sadly, most actual demos of Hydrogen always use BOUGHT tanks of compressed hydrogen gas, which thereby bypasses many of the difficulties of the technology.

So, even ignoring the problems discussed above regarding having to compress the Hydrogen to actually be able to use it, we now have somehow created maybe 100 cubic feet of Hydrogen. (That is a volume of five feet by five feet by four feet.) We noted above that each cubic foot contains 319 Btu of chemical energy. So we have 31,900 Btu of energy available. Maybe that sounds good, but your house furnace probably uses up 125,000 Btu/hr in the winter, so that amount of Hydrogen gas would only provide heat for a single house for around 15 minutes! But if we look at the energy consumption of the whole United States, each year, it is a little over 100,000,000,000,000,000 Btu.

Our energy amount above (the 100 cubic feet of Hydrogen gas) is equivalent to around 31 cubic feet of natural gas (at a little over 1,000 Btu/cubic foot). But each year, the US consumes around 30,000,000,000,000 cubic feet of natural gas!

See the problem? Even if the Hydrogen techlology could be scaled up by a factor of a MILLION (extremely hard to do!), it would then still only represent one one-millionth of our gaseous energy needs! (We have another web-page in this Domain that presents government and industry data on energy supplies and consumption rates, and it shows that, without imports, the US would completely run out of natural gas in a little over EIGHT years!) So that NEED for a gaseous fuel will certainly exist. But it is hard to see how Hydrogen could provide but the tiniest amount of that need.

Yes, I realize that the public and politicians seem fascinated with Hydrogen as the "answer to all the energy problems", but it is really hard to see how that could realistically happen. We humans have gotten spoiled by being able to consume and waste unbelievable amounts of coal, oil, natural gas and uranium. There seems to be no care at all regarding what people of 20 years from now will do! Some people say that "science will find solutions" but I ask that you note that I AM a Nuclear Physicist! If the US is not able to rely on friendly countries for Uranium, oil, and natural gas, we may all wind up in a Medieval United States! We already used essentially all the Uranium that was under the US, nearly all the oil (4.3 years supply left), and nearly all the natural gas (8+ years supply left). This is bad. Very, very bad. But I truly doubt that Hydrogen can provide any significant alternate source, mostly because our total energy consumption has been so amazingly high!

Another politically popular "energy solution", wind-generating of electricity, has many problems of its own, primarily transporting the electricity hundreds or thousands of miles, because very little actually gets to the end of those very long lines! Even with impressive government funding of wind-generation, it seems very unlikely that such systems can realistically provide more than the tiniest part of the US electricity usage. But it seems likely that politicians will go crazy and authorize a thousand times as many windmills than already exist. And the windmills will soon after be discovered to cause weather changes in the climate, because so much wind is slowed down such that normal weather patterns cannot occur.

The amount of power in wind energy seems impressive during hurricanes and tornadoes, true. But in NORMAL winds, which tend to average around 10 or 11 mph in many areas, the actual amount of electricity which can be produced from wind is not remotely comparable to our amazing consumption of electricity and other energy. Yes, when demonstration projects build hundreds of giant wind turbines (for billions of taxpayer dollars!), it CAN be shown to produce the electricity needed by some SMALL local town. And everyone celebrates as though they have found magical solutions! But they haven't! If we were in 1890, where there was extremely minimal usage of electricity, yes, those wind farms would be great! But our current usage of electricity is so many millions of times larger than what wind could provide, it turns out to just be a "wonderful idea"l which will not pan out as needed.

So the rather casual comments that "our technology will find ecologically sound ways to make electricity in the future" as the future source of the power to drive Hydrogen generation, is pretty close to Easter Bunny and Santa Claus sort of stuff.

It is really hard to see how the US will be anything other than a total-coal powered country within a few decades. We DO have a lot of coal!

Conclusion

Yes, Hydrogen can be demonstrated in experimental vehicles, and they can have impressive acceleration and speed. But that's with a rather small (BOUGHT!) Hydrogen tank aboard. If you ever see an impressive demonstration like that of a Hydrogen-powered vehicle, make sure to ask how long that vehicle could continue to perform like that. The answer is certain to be no more than a few minutes at most. So, as a demonstration, Hydrogen can seem quite impressive, because it is! But in actual practical applications, the details probably make it never to be usable in our vehicles.

In other words, one of the resulting products is the carbon dioxide that is blamed for much of global warming. But that is really NOT a fault IF the methane is PRODUCED as on a farm, as in that case both the production and oxidation of the methane is part of the natural Carbon Cycle. It is ONLY if the methane being burned had been brought up from being stored underground for millions of years. In THAT case, when it is burned, it releases NEW carbon dioxide into the atmosphere that had been removed millions of years ago.

It sure seems to me that methane is a FAR more attractive possibility regarding solving future energy needs than Hydrogen has any chance of accomplishing.

By the way, chemically, Methane is CH₄. Another immensely popular concept (but an incredibly expensive and foolish idea!) these days is Ethanol (or Ethyl Alcohol or Grain Alcohol) which is C₂H₅OH. Methane (gas) and Methanol (CH₃OH) (liquid) and Ethane (C₂H₆ (gas) and Ethanol (or wood alcohol) (liquid) are therefore similar chemically, all simple hydrocarbons, where a Hydrogen atom is in an (ane) is replaced by an Hydroxyl ion in the (anol). Some uses benefit from a gaseous fuel, while others benefit from a liquid fuel.

(Ethanol requires not only immense amounts of corn to be grown, at the expense of food crops, which has already [2007] caused grocery prices to rise tremendously, but it requires the heating and fermentation processes of a still and some other processes, and then has to be trucked around, together USING UP about as much (fossil fuel) energy that the Ethanol can eventually provide! AT BEST, we are simply WASTING all those millions of acres of corn crops! Interesting, huh?

Footnotes

Combustion of Gasoline

Automotive-related presentations in this Domain

Energy-Related presentations in this Domain:

( http://mb-soft.com/index.html )

C Johnson, Physicist, Physics Degree from Univ of Chicago