DAR
It seems to me that there is an amazing hoax going on. Hydrogen fuel cell cars. Scientific American had an excellent article on this some time back but I can't find it online. The following article makes a similar case. Why on earth are the wasting time with these ridiculous hydrogen cars?
***
The case for nuke cars—it's called 'hydrogen.'
BY PATRICK BEDARD, October 2005
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.
***
Car and Driver
Another good, short article can be found here.
