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Die Wundervolle Welt des Wasserstoffs
By Twisted Rhodes
This past year gas prices in the Bay Area have shot up far above the average cost in the U.S., and thoughts about alternative fuels have once again entered into the collective consciousness. The most talked about fuel of the future is hydrogen. This month’s column is a direct result of a conversation I had with my brother-in-law while vacationing on Cape Cod (where the prices—even after the blackout, a busted pipeline in Arizona, and profit driven increase—at $1.95 a gallon for 93 Octane seemed cheap to me).
It must have been synchronicity because once I began this column on hydrogen, several things happened. Nightline dedicated its August 25th (2003) broadcast to the subject (“Little Black Box”). Then, before the flight home, I picked up a copy of Scientific American which just happened to have a pointer to an online article on a recent discovery related to hydrogen production. And I found an June issue of Business 2.0 which also featured an article on it (“Mary Tolan’s Modest Proposal”).
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BMW Clean Energy vehicle
Photo: bmw.com |
You may remember a while back that Roundel featured articles about BMW’s efforts to promote hydrogen combustion engines. BMW AG’s fleet of clean-burning cars have been shown at auto shows and have even made a trip to the U.N.
BMW is not alone in promoting hydrogen. General Motors is spending research dollars on hydrogen burning engines and President Bush has been touting hydrogen-based fuel cells as the best way to produce electricity to power the drive wheels of future automobiles.
So, if people from the Sierra Club, to our self-pro-claimed Friend-Of-The-Environment President, to the world’s largest gasoline combustion engine producer are behind it, then it must be good, right? Do a little research, and you’ll find that there’s a lot more to the story. Yes, most of the problems are technical, which are probably all solvable given enough time, money and sociopolitical determination (this is the key.) What is often not mentioned is that we are a lot farther away from making a Hydrogen Utopia happen than most people want to admit.
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General Motors Hy-Wire
A Proof-of-Concept fuel cell vehicle incorporating many of the features of the GM Autonomy concept. Unveiled in August 2002.
Photo: General Motors, 2002 |
First, the basics of why we want use it in the first place. Hydrogen is the most abundant element around (it makes up 90% of the entire universe by weight.) It powers stars which are massive fusion reactors that transform hydrogen into helium. Each molecule of water has two hydrogen atoms (H20). Every organic compound has hydrogen. When it burns, it combines with oxygen to produce heat and water. It sounds perfect; it’s everywhere and clean.
Today, the two sources of motivation for an automobile are internal combustion engines and electric motors. Using hydrogen to replace gasoline in an engine is not all that difficult. There aren’t a lot of modifications required to covert current designs for hydrogen use, so BMW’s expertise in motor technology will no doubt give us great performance. Fuel cells are ideal sources of power for electric automobiles because they use hydrogen and have a much better power-to-weight ratio than batteries (which also have a huge amount of pollutants in them and a finite life requiring disposal/recycling).
Hydrogen may be plentiful, but getting in a state where it’s ready to burn is not that simple. Right now, the primary sources being considered for production of quantities needed for use as a fuel are water and petroleum-based hydrocarbons.
Since water is the most common source on Earth, let’s start with there. Unfortunately, hydrogen really loves oxygen and it takes quite a bit of effort to liberate it from its bonds. It actually takes more energy to break the chemical bonds in water than to make it. About 1.2 kW of energy is required to produce enough hydrogen for 1.0 kW of power when it’s burned in a combustion engine. Since the most common sources of power for separating water into oxygen and hydrogen is coal, natural gas and oil, we gain no real benefit from wasting 20% of hydrocarbon fuel for hydrogen fuel. We could resort to nuclear fission reactors to power this process, but that’s not going to happen any time soon. (When was the last time you heard of a new nuclear power plant coming on line?) The other sources of clean power to produce hydrogen have all sorts of problems – mostly political – which hurts the overall potential for hydrogen production from water.
What about petroleum-based hydrocarbons? Well, hydrogen doesn’t have the same attraction to carbon as oxygen so it’s not as hard to set it free. As a result, the energy equation is a lot more favorable: it takes about 0.6 kW of power to produce 1.0 kW of hydrogen power. Even factoring in the energy used to find, acquire, refine and deliver the hydrocarbons needed for the source of the process, it’s still a net gain—0.8kW to produce 1.0 kW of hydrogen power. This process, called “reforming,” is well understood and has been around for many decades— another positive aspect.
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Shell Hydrogen station in Iceland
The station was opened in April 2003 and is located next to an existing Shell station in the east of the Icelandic capital.
Photo: Shell Hydrogen |
One downside to the reforming process, however, is oxygen’s fickle nature. Oxygen just happens to really love a lot of other elements, like iron. (Just ask any 2002 owner in the Northeast about the marriage of iron and oxygen). The reforming process divorces carbon atoms from hydrogen and get picked up by oxygen on the rebound to form CO and CO2.
Some people want you to believe that the process of reforming petroleum-based hydrocarbon yields less greenhouse gases than simply burning them directly. Not true—the total number of carbon atoms is the same for combustion and reforming and they all end up bound to oxygen as CO and CO2.
So far, things don’t look too bad, but “The Wonderful World of Hydrogen” has more issues the general public doesn’t know about. Is it a conspiracy? Stay tuned for part two to find out. 
TwistedRhodes@ggc-bmw-cca.org
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