Posted on 01/25/2002 12:12:08 PM PST by John Jamieson
John R Jamieson MIT67, NASA67-94 retired
It seems like a great idea at first glance. Hydrogen is one of the most abundant elements on earth and burns very cleanly. It contains more energy per pound than any other fuel.
At second glance, things are a little less encouraging. Most of the hydrogen on earth is already burned! The oceans are the ashes of billions of years of hydrogen fires. The hydrogen is tightly bound to oxygen atoms and must be separated from those atoms before it can be used again. Using electrolysis, the hydrogen can be separated from the oxygen by putting in exactly the same amount of energy that will later be retrieved when the hydrogen is burned. Hydrogen, made from water, is thus an energy storage media like a battery, not an energy source. Neither the separation nor the recombination of this reversible process can happen at 100% efficiency. Waste heat is generated during each process. Because most of our electricity is generated by hydrocarbons, we would still be using hydrocarbons to run our cars. The inherent efficiency of the electrical energy generation process (about 40%) times the expected efficiency of the electrolysis process (about 50%) would indicate a hydrogen fuel price of about 5 times the price of fossil fuels.
The second major source of hydrogen is directly from hydrocarbons. Hydrocarbons contain both hydrogen and carbon; about twice as many hydrogen atoms than carbon atoms, but since a carbon atom weights 14 times more than a hydrogen atom, much more carbon by weight. When we drive our cars today, we burn about 5.3 pounds of carbon and .7 pound of hydrogen per gallon of gasoline. Hydrogen plus oxygen equals water, good; carbon plus oxygen equals carbon dioxide, bad (the same stuff we exhale!). If we could breakdown natural gas, methane, gasoline, or fuel oil to separate the hydrogen from the nasty carbon (on which all life is based) and sell the huge piles of carbon for enough to pay for the separation, about 3 gallons of liquid or an equivalent weight of gas (about 18 pounds) would yield about 2 pounds of hydrogen, which is the energy equivalent of 1 gallon of gasoline or 6 pounds of natural gas. Remember that burning the carbon would not be allowed. We could make diamonds with it. The net result is that hydrogen fuel cannot, ever, be made for less than 3 times the price of fossil fuels.
OK, what if we just ignore that fact that we can’t make hydrogen economically. What do we do with it in an automobile? The logical answer is we burn it, in the same cars we’re driving today. Internal combustion engines basically don’t care what provides the heat. There are a few minor problems: How do you seal up the leakiest substance known to man? How do you store enough in the car to go 300 miles? What happens in a freeway crash? Etc. But, these little issues can all be solved. IC engines will need water injection to lower peak cylinder temps so we don’t make nasty NOX, but that technology is pretty well understood. Oh, but wait a minute, IC engines are nasty and unacceptable! Enter the miracle solution: FUEL CELLS!
FUEL CELLS work! There is about a $100,000,000 worth of them on each Space Shuttle generating the equivalent of almost 36 horsepower. Coleman just announced a real commercial home power generator that puts out 1.2 kilowatts for only $7,995 (Plus $100 per hydrogen canister that lasts for a few hours). GM just drove its latest fuel cell vehicle “Hydrogen1” on an “endurance test”, 230 miles from LA to Los Vegas. They only had to stop 7 times for more hydrogen. Many other companies built fuel cell cars and tried to go along, but didn’t make it. Zero to 50 was only 18 seconds.
The US department of energy recently set a goal of only $400 per kilowatt (about a horsepower, figuring electrical controller and motor efficiencies) for STATIONARY APPLICATIONS BY 2015. Won’t they be surprised that Detroit is planning affordable family fuel cell automobiles by 2010! If Detroit gets to magic $400 per horsepower five years early, and makes it small enough and light enough to go in a family car, you too, could be driving a 200 horsepower family car for a little over $100,000 that “burns” hydrogen costing you $5 a “gallon”. What a deal! You’ll drive it with pride knowing that your leaving no bad stuff in the air of your immediate area, while increasing the pollution of the poor people that live next to the power plant outside of town by a factor of 3 and increasing the importation (and probably the price) of Arab oil by a factor of three.
All this negativity aside, there is one and only one way to cheap automotive fuel, clean air and energy independence for this country. The answer is a massive, nuclear energy economy, probably fusion (hydrogen) powered. Hydrogen used for fusion generates power thousands of times more effectively than burning it with oxygen. A national effort equal to the Manhattan project or the Apollo program could develop fusion-powered electricity (and cheap hydrogen for automotive fuel) within 25 years. Then, we can truly say, we’re driving clean, fusion-powered cars. Electricity could be as cheap as 2 cents per kilowatt-hour and hydrogen for our cars, 40 cents per “gallon”. It is the only solution to the problem that has any economic, political, or engineering viability.
In the meantime, burn all the cheap Arab oil you can get and keep supporting the development our own fossil fuel sources for the day when we decide to shut the Arabs off!
If the fuel cell is so impossible, why is a Saudi prince telling his country that they need to diversify their economy? ;)
THE key point that you fail to consider and the real limiting problem with vehicular fuel cell technology has been that the amount of platinum catalyst needed to build the cells was simply too high (those NASA fuel cells are OLD OLD technology and use LOTS of platinum). That problem has been whipped, and the needed amounts of catalyst reduced by at least one order of magnitude. Another was that the efficiency dropped off drastically when using air as the oxidant (the NASA cells used pure oxygen). Ballard has whipped that problem on their PEM fuel cells, and current cells are as efficient on air as older cells were on pure oxygen.
REALLY??? Then the cost of diamond jewelry must have dropped a lot lately.
You do know who to listen to, and you know who you are listening to. You are way ahead of most people, and in the right place [FR].
http://www.academicpress.com/epst/biomass.pdf
Of particular interest is the conclusion regarding ethanol production from corn:
"Assuming a net production of 433 liters of fuel per corn hectare and if all automobiles in the United States were fueled with ethanol, then a total of approximately 900 million hectares of cropland would be required to provide the corn feedstock for production. This amount of cropland would equal nearly the total land area of the United States."
"Brazil has been a large producer of ethanol, but has abandoned subsidizing it. Without the subsidy, economic ethanol production is impossible."
So the good news is that we could do it, the bad news is that we would all starve.
Pound for pound, not counting substrate, just active ingredients. $5 per watt for a microscopic layer of silicon is priced beyond my means.
No--these would be for central power and possible home use. SOFC are too thermal shock sensitive for use in vehicles. The PEM fuel cell is the one of choice for vehicular.
Not in our or our childrens lifetime. There have been predictions of fossil fuel shortages since the teens. Nada. More or less, every year known reserves increase faster than demand. Productions costs continue to decrease over time. Sorry.
Actually, your 92 octane is far more dangerous than hydrogen. Also, BTW--the Hindenburg catastrophe was caused by a lightening strike igniting the metallic aluminum and dope coated fabric of the Zeppelin's skin (see "solid rocket fuel"). The burning fabric then ruptured and ignited the hydrogen lift cells. There is a good web article about it.
Nope, but when I fully retire and move to the backwoods, I very likely will. Of course, I am really waiting for the combined electrolyer/fuel-cell/tank unit that can be coupled to solar cells to replace the battery bank.
Ethanol from corn was a crackpot idea from the start. It was pushed to try to do something with all the surplus corn stacking up in Iowa.
The REAL alcohol of choice is methanol, which can be VERY easily produced from natural gas, agricultural waste, coal gasification, and a whole host of other carbon sources. It can be burned in today's IC engines with only minor modifications, and will also work directly in fuel cells (see "direct methanol fuel cell"). It is the REAL liquid fuel of choice.
About a thousand years ago, there was a book titled Common Sense in Nuclear Energy written by Fred & Geoffrey Hoyle. It was good then and it's still good today. Find it and read it.
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