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!
The direct methanol fuel cell is a real item and still developing. It's here now, it will get better with time.
Finding a way to contain a plasma at 25,000 degrees for starters. It's way more than your average thermos can handle.
Quick explanation. A large electricity plant, of whatever kind, cannot be shut down for so short a period as overnight. So electricity companies have for years been selling cities "street lights" in an attempt to get a few bucks out of this otherwise wasted energy.
I live in a city that has basically banned street lights. It's one of the safest cities in the area (so much for the "security" part of lights). And its wonderful because you can see the stars at night.
So, shut off the street lights. Generate the hydrogen. And at whatever ineficiency that might be, its still better than totally wasting the energy.
EBUCK
Using any form of energy you can think of kills people.
Since I've never seen the scrutiny of energy like the anal exam of nuclear (what was the cost, $10 billion, just spent so far on one silly mountian in NV for studies. And they want to continue studies another 10 years!) I'll just assume that these other forms are just as dangerous. But they're just not quite as politically incorrect.
You process them to recover unused fuel and to recover plutonium to make more fuel. You then exercise good engineering judgement and manage the remaining high-level wastes where they will not get loose in the environment.
You also quit wetting your pants worrying whether someone will steal them and put them in the mashed potatoes in school lunchrooms.
It is until you start looking at the acreage required to supply the equivalent of 30 billion gallons of diesel per year. Even if biodiesel made up 2% of the total, it's tens of millions of acres.
It is until you start looking at the acreage required to supply the equivalent of 30 billion gallons of diesel per year. Even if biodiesel made up 2% of the total, it's tens of millions of acres.
Did you send your 5 clams?
EBUCK
Hey there all eco-freaks! Take Physics 101! Reality is a bitch - get educated or shut up.
The only way that hydrogen gereration is possible as an economic alternative to natural gas is to use solar cells by the ocean for its generation. I doubt that it would ever be cheaper than bio-mass sources of methane.
Besides, your exhaust smells like popcorn!
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