Posted on 09/23/2005 2:19:38 PM PDT by newgeezer
Funny thing about hydrogen cars: If we were all driving them now, the President's FreedomCAR initiative would be anteing up its $1.8 billion to invent the gasoline engine. Freeing us from hydrogen would be "the moral equivalent of war," to use the words of a long-past energy-crisis president. Gasoline would be the miracle fuel. It would save money by the Fort Knoxful. It would save energy by the Saudi Arabiaful.
To see why this is so, let's look at the numbers. And for once, we're talking about a miracle fuel without speculation. We can see exactly how the "gasoline economy" would work by looking back to a year that's already happened. In 2000, gasoline consumption averaged 8.47 million barrels per day. Gas contains 5.15 million British thermal units of energy per barrel. For big numbers like this, it's customary to think in "quads," or quadrillion BTUs. So the gasoline energy used by motor vehicles in the year 2000 worked out to 16 quads.
Now let's do the same driving in hydrogen cars. Hydrogen is the most plentiful element on earth, but there's no underground pool of it we can drill into. All of nature's hydrogen atoms come married to other atoms in earnestly stable relationships. It takes an industrial process to break apart those marriages to obtain pure hydrogen in a form that can be used by fuel cells.
Think of fuel cells as black boxes into which we put hydrogen on one side and oxygen from the atmosphere on the other. Out the bottom come water and a small electrical current. There is no such thing as free power, of course. If you get power out when you let hydrogen and oxygen get married in a fuel cell, then you must put power into the process of divorcing them.
The industrial divorcing of water molecules is known as electrolysis. This is fuel by immaculate conception, according to most greenies. To make the chemistry work, you must put in 39.4 kilowatt-hours of energy for each kilogram of hydrogen you expect to liberate. Unfortunately, the electrolysis process is only 70 percent efficient. So the total energy input must be 56.3 kilowatt-hours per kilogram of hydrogen.
This energy to be added must come from somewhere. The U.S. has an excellent supply of coal. Coal-fired powerplants are about 40 percent efficient, so 140.8 kilowatt-hours of coal energy are required to net the 56.3 kilowatt-hours of electricity to produce our one kilogram of hydrogen.
My source for these calculations is Donald Anthrop, Ph.D., professor emeritus of environmental studies at San Jose State University, in a Cato Institute report.
In a perfect world, the fuel cell in our car would produce 33.4 kilowatt-hours of useful energy from each kilogram of hydrogen, and 6.0 kilowatt-hours would go to water vapor, giving you back your net investment of 39.4 kilowatt-hours at the electrolysis plant. But the world is not perfect, and the best fuel cells are only about 70 percent efficient. So the energy yield is 23.3 kilowatt-hours.
One more loss must be reckoned with. Hydrogen is a gas. It's lighter than air. Remember, it was the stuffing for the airship Hindenburg. Hydrogen gas (at atmospheric pressure and room temperature) containing the same energy as a gallon of gasoline takes up 3107 gallons of space. To make a useful auto fuel, Anthrop says it must be compressed to at least 4000 psi (Honda uses 5000 psi in the FCX; GM is trying for 10,000). The energy required to do that further trims the yield to 17.4 kilowatt-hours. Pressures higher than 4000 would increase miles available from each fill but cost more energy for compression. Liquefying hydrogen, which BMW advocates, costs upward of 40 percent of hydrogen's energy content.
So far, the numbers say this: Starting with 140.8 kilowatt-hours of energy from coal gives you 17.4 kilowatt-hours of electrical power from the fuel cell to propel the car, or an energy efficiency of 12 percent.
Anthrop goes on to estimate the fuel-cell power needed for the 2.526 billion miles driven in the U.S. in 2000. According to Southern California Edison, the electricity needed per mile for passenger cars is at least 0.46 kilowatt-hour. For the whole U.S. vehicle fleet, that works out to 1.16 trillion kilowatt-hours. You'll need 32 quads of coal, which is twice the energy actually consumed in 2000 with gasoline.
As for global-warming implications, the use of hydrogen from coal instead of gasoline would produce a 2.7-fold increase in carbon emissions.
Of course, all of today's electricity doesn't come from coal. But even with the current mix of sources, including natural gas, nuclear, hydro, solar, and wind, that much hydrogen would raise our carbon output to about twice the 2000 level.
The enviros like to talk about renewable energy. Anthrop has done those calculations as well. Hydro power is our largest source of green electricity, but it would take 15 times the current amount for an all-hydrogen vehicle fleet. Given the pressure to remove existing dams, it's unlikely we'll have any additional hydroelectricity.
Photovoltaic cells? Anthrop says it takes about eight years of cell output to make back the electrical power originally consumed in manufacturing the cell.
Wind power? It defies calculation, in part because wind blows only intermittently.
Virtually all the hydrogen produced today, about 50 million tons worldwide, comes from natural gas. The process, called "steam reforming," is only about 30 percent efficient, much less, he says, "than if the natural gas were simply burned" in the generating plant.
Producing enough hydrogen to replace gasoline by reforming natural gas would increase our gas consumption by 66 percent over 2002's usage. And don't forget the carbon emissions.
That leaves the unspeakable—nukes.
Presumably, BMW knows all of this, yet it has been thumping the tub for hydrogen since the 1970s. Along with hundreds of other invitees, I attended BMW's hydrogen hootenanny at Paramount Pictures in 2001. Mostly, it amounted to a day of corporate preening before California's greenies. Still, BMW is famously brave in confronting technology. Does it have a plan? I summed up the science of this column, in writing, and passed it up through BMW's official channels, along with the obvious question: Where will the necessary quads and quads of energy come from for hydrogen cars? That was nearly two years ago. BMW has not answered.
No answer, of course, is the anwer.
With all its inefficiencies, the only real advantage of using hydrogen as a fuel source is that it can be burned without producing waste carbon to eneter the atmosphere. But extracting hyrogen directly from coal, by any process and regardless of other coproducts, still releases trapped carbon. And that defeats the only real point of moving to a "hydrogen economy".
The other stated purpose of the "hydrogen economy", energy independence, simply doesn't make sense for coal sourced hydrogen. Again, hydrogen's inefficiencies mean it would make more sense to make cars that burn coal directly. A coal driven car would release less carbon and yield more usefull energy than a car fueled by coal sourced hydrogen.
Bad as it paints the picture, it leaves out another dirty little secret. Hydrogen oxygen fuel cells depend on a platinum catalyst. Platinum is rarer then gold and more expensive. There is no domestic source of platinum, we'd have to buy it on the world market.
More food for thought!
Regards,
GtG
It costs about $30/barrel to make gasoline from coal!
http://www.newton.dep.anl.gov/askasci/chem03/chem03328.htm
Back in 1949, the Bureau of the Mines in Louisville, Missouri put together a demonstration plant to produce gasoline from coal. Raw coal was first crushed to about 3/4 inch size and then pulverized in a ball-mill to less than 60 mesh, then dried to 1 or 2 percent moisture content. This is mixed with a small quantity of catalyst, such as iron oxide or tin oxalate, and with a heavy oil into a paste containing about 47 percent solids. Steam-driven pumps at 10,000 psi force this paste into a radiant-type heater in which the high pressure tubing is protected
by a superheated jacket. The plant was designed to work at 700 atmospheres or over 10,000 lb. pressure, in two major steps. This liquifies the coal and produces gasoline and its by-products. The output of the plant was from 300 barrels of gasoline per day depending on the coal used and the catalyst used.
Taken from ENCARTA 2004 by Microsoft.
That's not the point. The energy used to refine gasoline comes from the oil itself. Gasoline doesn't hold all the energy from the oil consumed to produce it, but it's still a positive net energy transfer from the well to your fuel tank.
Producing hydrogen, by any method, requires an external energy source. Unless someone figures out a way to get energy from the water used to produce hydrogen by electrolysis, hydrogen production is a net energy sink. The last time I checked, such an energy source (nuclear fusion) was still many many decades away. And has been many decades away for decades now.
Look toward Purdue University the brains of the country...
Yes, hydrogen is a way of making nuclear power portable. But the article errs in writing off fitful, opportunistic sources of energy (wind, wave action, etc. If a safe way can be found to bottle hydrogen between energy source and automobile, any of these sources can also be used to store energy as hydrogen. If the wind blows hard enough for one month of the year somewhere, that's still a valid source of hydrogen.
Not entirely a valid point. Traditional fuel cells do use platinum as a catalyst. But then so does the catalytic converter on your car's tail pipe. A hydrogen fueled vehicle wouldn't need a catalytic converter to convert unburned hydrocarbons in the exhaust. So essentially it would just move the platinum from one end of the engine to the other.
I do have to give the hydrogen fuel cell pushers a little credit here. Most of the fuel cell research these days has gone into developing efficient membranes that do not contain platinum or other rare materials.
The fuel cells themselves are not really an issue in the hypothetical "hydrogen economy". Especially when there are so many problems with using hydrogen at the hydrogen production end.
Really? Well you must know something that everyone else here doesn't. Please, share your knowledge.
You'll need wheels and wheel bearings. Even the diesel-electric locomotive has wheels.
From the sun .... solar water splitting. Think of it this way .... how much energy does it take to power all the vehicles in the world compared to how much energy it takes to warm and sustain a sphere 25,000 miles in diameter 93 million miles away? The answer cannot be expressed in 'quads' if it is to be meaningful. The answer is 'a hell of a lot'. We have the sun ... we have the water (70% of the earth) ... we have only to learn how to take advantage of the obvious.
This seems to be a level-handed, hard-hitting analysis of the fallacy of running a car on hydrogen anytime soon.
And yet still, the Stupid idiot of a Governor in california.
Big doofus Arnold, says we must invest in Hydrogen as the next Fuell for cars...California's next Disaster.
He will probably be reelected.
Would that be with the classic hyperbolic cooling tower in the back?
Yes, it is the sports model, two seats.
The eight year estimate for solar panels producing the energy required to produce them is a little optimistic. Most estimates I've seen is ten to fifteen years. Solar panels, for the first decade they're used, are not so much an energy source but rather a way to pay for ten years of electricity up front. They are simply not efficient enough or cheap enough to be a viable means for efficient hydrogen production from electrolysis.
how much energy does it take to power all the vehicles in the world compared to how much energy it takes to warm and sustain a sphere 25,000 miles in diameter 93 million miles away?
But that's not the point. Yes, a lot of energy come to the earth from the sun every day. But how is that energy going to be collected, stored and transported? The real issues with energy use are always issues of collection, storage, and transportation. Why do you think we use fossil oil and coal? Because the energy in the fossil fuels has already been collected by plants over billions of years and stored by them in an easy to transport form that we can go out and dig out of the ground.
we have only to learn how to take advantage of the obvious.
But the "obvious" comes with a plethora of not so obvious pitfalls and technical hurdles for us to overcome. If a solar powered hydrogen economy were really so obvious and simple, we'd be running one right now.
I want to be the first one on my block to drive a coal-powered car. Very cool.
Up to now cheap oil has been selling for $20-25 per barrel. This will not be the situation in the future because demand will exceed supply ..... India and China have joined the demand side of the equation. Until now hydrogen was not economically competitive so capital was diverted to oil exploration, etc. This will not be the case in the future. Oil will be around for a long time but it will slowly be replaced by hydrogen and nuclear energy.
While looking for a photo of post war Japan with cars using hot coal vapor (they had a large bladder on the roof) I found some helpful tidbits.
Drive a Coal Powered Car
PROS: Uses cheap, clean coal.
CONS: Shoveling coal while driving is almost as distracting as talking on the phone. With the open flame there, you made need a drink to calm your nerves.
http://www.imao.us/archives/001506.html
ROPER, SYLVESTER HOWARD
Sylvester Howard Roper (1823-1896) was an American inventor from New Hampshire and Massachusetts. Roper developed a coal-powered, two-cylinder, steam-driven wooden motorcycle in 1867. Roper also developed a steam-driven car. Roper died at the age of 73 while testing a new motorcycle.
http://www.enchantedlearning.com/inventors/transportation.shtml
LoL
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