 by Preston MacDougall April 08, 2005
If my family and I were on one of our numerous cross-country treks, such a question would normally come from somewhere in the back. Lately, however, it is more likely to come from the bookkeeper in the family, seated in the front passenger seat. And the setting isn't likely to be a jam-packed interstate, but rather a local gas station, as I, the chauffeur in the family, pump away. Meanwhile, the numbered wheels in the "THIS SALE" window are spinning at rpm's that I normally associate with a one-armed bandit in Las Vegas.
It could be worse, and probably will be. At least gas is still cheaper than milk, by the gallon, at most places in the US. But the big oil fat cats are quickly catching up to Old McDonald's Jersey cows. Gas has already passed the three-dollar mark at some places in California, which is also where you are more likely to hear, and read, about the so-called "hydrogen economy". Last year, the National Academy of Engineering recently published a comprehensive report entitled "The Hydrogen Economy: Opportunities, Costs, Barriers and R&D Needs." Five of the fifteen members of the committee are from the Golden State. Readers who have come to dread the needle falling below the E can access this book online, for free. Go to books.nap.edu and enter "hydrogen economy" in their search engine. Don't expect much relief, however, unless you suffer from insomnia. Hydrogen is the lightest element, but there is a ton of thermodynamics in this report. Around the same time that the committee issued their report, one of my Honors Chemistry students, Sarah McCormick, delighted me with a collection of Haikus of the Periodic Table. Befitting its place at the head of the table, the first one was titled "Hydrogen." It's the smallest element. It is number one! She might have used her poetic license regarding hydrogen's size, since, unless it is excited, an atom of helium is slightly smaller than an atom of hydrogen. It may sound strange to talk of atoms getting excited, but that is the proper term when energy is absorbed form the environment. During an MRI scan, it is the nuclei of the hydrogen atoms in bodily fluids and tissues that absorb and emit radio waves, which are what is being monitored. The atoms do this constantly, whether we are dead or alive. The big magnet that patients are placed within merely amplifies the signal and allows for better contrast in the image between healthy versus cancerous tissue, for instance. Basically, the hydrogen atoms, which are very small magnets themselves, have resonances at different radio frequencies when situated in these different environments. The electrons in atoms can
also absorb and emit radiation, and this is often in the visible
part of the spectrum. For example, the electrons in neon atoms
give rise to a neon red glow when electricity is passed through
neon gas. A similar set-up, but with hydrogen gas, glows with
a beautiful mauve color. Depending on what a hydrogen atom is bonded to, the electrons making up the bond can be relatively high or low, energetically. In the case of carbon, as with the hydrocarbon molecules in your gas tank, the electrons have a high energy. In the case of oxygen, as with the water molecules coming out your car's tailpipe, the electrons have a low energy. According to the First Law of Thermodynamics, which states that the total amount of energy is conserved, the drop in energy between gas tank and tailpipe, experienced by the electrons in the hydrogen atoms and their bonding partners, must be balanced by a gain in energy somewhere else. The drop can occur during a combustion reaction, or an electrochemical one in a fuel-cell. It is the job of engineers to efficiently employ the energy gain. So, from the perspective of a chemical eye, we already have a hydrogen economy, partly. The remaining task is to chemically, and efficiently, obtain the hydrogen atoms from renewable sources, instead of from oil in the Middle East, or the Arctic, or anywhere else. If a research effort comparable
to the Manhattan Project were devoted to this problem, I imagine
that four-wheeled "Hydrogen Bombers" would soon be
flying off showroom floors.
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