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HYDROGEN: Fuel of the (near) Future

March 2003
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HYDROGEN

In the beginning, there is hydrogen, the first element, the simplest atom—one electron, one proton—that’s it. Hydrogen is the most plentiful and ubiquitous substance in the universe, representing about half of all matter, and it is everywhere—in the rocks and soil, in the air and especially in the water that covers three quarters of the globe. If God made light on the first day, he must have spent at least the whole morning of the second giving form to the void in the way of this prima materia. In fact, modern physics has discovered that hydrogen atoms apparently materialize spontaneously in space, curiously validating, after lo these many millennia, the words of Genesis. From some unknown void, perhaps the far side of a black hole, form is given.

Hydrogen is a gas at normal temperatures. It is highly reactive, combining readily with a number of elements and compounds, the most familiar example being oxygen to form water (H20). The 2H + O = H20 (hydrogen plus oxygen equals water) combustion reaction is highly charged, explosive, producing a great deal of heat as a by product, thus making hydrogen a true competitor with fossil fuels as a source of power.

The same reactive quality that makes hydrogen a good fuel source, however, also makes free hydrogen rare in nature—it is almost always found bound to other chemicals. One of the challenges, then, of moving to a hydrogen energy regime is to develop economical ways of freeing hydrogen from the chemicals to which it is bonded so it can be used as a fuel, then returned to nature.

While there are many compounds containing hydrogen and, thus, many methods for its extraction—too many to go into here—the ideal, and certainly most universally available source is water itself. Extracting hydrogen from water is simple enough, in principle, through a technique known as electrolysis in which an electrical current is passed through water breaking down its molecules into their component hydrogen and oxygen ions, both of which can be put to various uses.

The beauty of getting hydrogen from water is that, upon combustion (oxidation), it turns back into water. Only steam comes out of the tailpipe of a hydrogen combustion engine or fuel cell, steam that rejoins the planetary water cycle—there is no pollution and no net loss of resources. (Though our cities might get a little foggy, one observer quipped.)

The only problem with the water-to-water scenario is that electrolysis, at present, is expensive—hydrogen currently costs about three times as much as it’s fossil fuel competitors. This is mostly a problem of scale, however. As more and more hydrogen fuel applications come on line and the demand increases, mass produced hydrogen costs will drop. Another aspect of the problem, though, is that the cost of electricity for electrolysis is increasing, and most electricity, as discussed above, is produced by environmentally degrading technologies such as coal fired and nuclear power plants or hydroelectric dams.

Again, the solutions are at hand, and do not require any technological breakthroughs. Renewable electrical production through a widely distributed network of wind, photovoltaic, biomass and geothermal plants can eliminate most of the environmental hazards and, potentially, greatly reduce the costs of electricity. This same network would, ideally, meet the electrical needs of our built environment, using surplus power and power generated at off-peak hours to produce hydrogen. (Currently, many power plants are idle in the wee hours of the morning when electricity, which cannot be stored, is not being drawn through the grid. Firing up our existing plants during off hours would burn more fossil fuels creating more polution, of course, but there is no reason not to run wind or biomass generators twenty-four/seven.)

Hydrogen can be extracted from a variety of compounds other than water. Many organic compounds including fossil fuels (especially propane, or natural gas) are currently used as sources of industrial hydrogen. Methane (swamp gas) is produced by rotting vegetable matter, and is therefore renewable. Many farms compost their waste material such as corn stalks to produce methane in small but usable quantities. Methane, in turn, can be broken down for its hydrogen content. While organic compounds are not are as desirable as water, from a purely ecological point of view, they may provide technologically appropriate, practical, short-term sources of hydrogen for certain countries or communities.

Like any other volatile fuel, hydrogen must be safely stored once it is extracted. Novices to the hydrogen fuel field frequently allude to the explosion, in 1937, of the German airship Hindenberg. Newsreels of this horrific event left indelible images of a huge passenger balloon filled with a dangerous gas exploding spectacularly while docking in Lakehurst, New Jersey, after a trans-Atlantic flight. The hydrogen did indeed explode, once the burning skin of the balloon touched it off, and people naturally attributed the disaster to the volatile gas.

Investigating German scientists, however, concluded that the airship caught fire because of the powdered aluminum coating on its skin which attracted static sparks (from the landing tower) and was easily oxidized. Recently, American aerospace engineers have confirmed that conclusion. Even if the Hindenberg had been filled with inert, non-combustible helium, as most modern balloons are, it would have burned. And although hydrogen is potentially explosive, it dissipates quickly upon combustion, and is therefore not nearly as dangerous as an equivalent quantity of gasoline (for a fascinating discussion of the Hindenberg fire, see http://www.clean-air.org/hindenberg.htm).

Hydrogen may be stored as a gas in pressurized tanks, or may be cryogenically liquefied. It can also be rendered essentially inert by combining it with other elements to form hydride powders from which the hydrogen can later be easily released. Delivery systems for mass distribution would be similar to those used today for fossil fuels. Specialized trucks for delivery to fueling stations, pressurized canisters of varying capacity for storage and underground pipes similar to those used to deliver natural gas to homes must be designed, manufactured and installed on a massive scale.

Finally, for the hydrogen economy to grow, people must be retrained, if only slightly, to safely and properly handle this new fuel and the vehicles, machinery and homes that it powers. They must accept and understand hydrogen equipment, as they once learned to accept and, eventually, embrace the automobile. And they must be informed, and inform themselves, about the options for the development of the hydrogen economy, which will be paid for by their taxes and discretionary income, so they can vote and purchase wisely.

Prototype Hydrogen Fueling Station at the California Fuel Cells Partnership near Sacramento, California.

The primary barriers to the construction of a renewable energy infrastructure are political—we are still hung up on oil. But the fossil fuel era is clearly coming to an end. Also, the electrical infrastructure—power plants and grids—of America and most industrialized countries is aging and will need to be replaced in the coming decades. Practical considerations will dictate that it is at least partially replaced by renewable power facilities which can cleanly provide the electricity needed to produce hydrogen.

The hydrogen revolution is, at the moment, at a chicken-and-egg impasse. Other than a few well-developed, operating prototypes, there are practically no hydrogen powered vehicles, machinery or buildings. There is therefore little demand for hydrogen other than for industrial purposes, and it is not available to the average consumer. On the other hand, hydrogen powered equipment is not likely to appear until hydrogen for refueling is readily available. If someone gave you a hydrogen car, where would you fill it up?

The situation, however, is not dissimilar to that of a century ago at the birth of the automotive age. We had to simultaneously perfect and mass produce cars, build an infrastructure for extracting, refining and distributing gasoline and build a nation-wide road network capable of accommodating the new vehicles. A government-industrial partnership accomplished these goals in a couple of decades, even with last-century’s comparatively limited technology and capitalization.

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