Editorial Comment

	Vol. 226 No. 3
PERRY A. FISCHER, EDITOR

The hydrogen economy. The much ballyhooed hydrogen economy is a far-sighted product of dreamers. But it is possible that the dreamers can win. Achieving hydrogen as a preeminent energy carrier will require technology advances that cannot be counted on, certainly not predicted. It is completely logical yet, thus far, undoable on a large scale, because logic alone is not sufficient.

While I should be disappointed by misconceptions from what are otherwise well-educated, highly intelligent folks, my years behind both sides of a bar have taught me that the average man, regardless of background, often has strong feelings about a wide variety of subjects, as I have been on the listening end of many an alcohol-induced diatribe about plutonium, dioxin, meteorology, geology, animal husbandry, and the speed of light, even though the speaker may have spent his entire life mining peat moss.

To make hydrogen a commonly available fuel, you need engineers and scientists who can explain the problems dispassionately. But due to the difficulty of communicating to a harried and often poorly informed public, there is usually only time for sound bites and slogans from journalists and pundits echoing political drivel. Here, I’ll try to shed a bit more light on the road to that imagined, energy-rich, squeaky-clean future.

A hydrogen-based energy future begins with the observation, usually as a young student, that hydrogen sits at the top of the table of elements. Most of the logic driving its use is that it is the most abundant element, comprising 75% of the universe and is, thus, inexhaustible. The other logical part is the fact that it burns clean when combined with oxygen, giving off only heat and water. It is ideal for certain types of fuel cells.

On the downside, although it’s the most abundant element in the universe, that top position in the table of elements also means that it is highly reactive. This means that hydrogen is almost always bound with something, often carbon in the form of oil, gas and coal, or bound with oxygen in the form of water. So, depending on your hydrogen source, it is likely that, at least in the interim period, you will still have importers and exporters, and all the issues of security, economics, and conflict that go with uneven resource distribution.

While hydrogen has inherently less pollution potential than conventional fuels, because carbon and sulfur aren’t burned, if you burn hydrogen with ordinary air, it can cause some minor pollution in the form of oxides of nitrogen, because air is mostly nitrogen.

In addition, if the life cycle of producing and using hydrogen is considered, including emissions of carbon dioxide and methane related to extracting the raw materials to produce, process, refine, transport and distribute it, the net decrease of greenhouse gas emissions may be much less than hoped for, depending on the methods used to produce the hydrogen.

For instance, using present electricity sources to derive hydrogen from water, the net reduction in carbon dioxide emissions from fuel cells compared to conventional engines would be as little as 4%. Stripping hydrogen from gasoline through chemical reaction would lead to carbon dioxide reductions of about 22%. But natural gas derived hydrogen would cut emissions by about 72%.

Hydrogen is already a large and mature global industry, producing one-fourth as much volume of gas each year as the global natural gas industry. Worldwide, over 17 trillion cubic feet is provided each year. About 48% is reformed from natural gas, 30% from oil and 18% from coal. Only 4% comes from disassociating water. Expanding this industry to widespread hydrogen use is not as big an obstacle as you might have heard.

Natural gas is widely seen as the easiest fuel from which to derive hydrogen. Obviously, only considerable Arctic gas or a much larger LNG supply could meet the soaring gas demand this would eventually require for transportation.

To achieve the maximum benefit, hydrogen needs to be produced from water rather than from fossil fuel sources, but that would require some sort of breakthrough in electricity production costs, including renewable sources.

Other breakthroughs are needed. For transportation – which is key for a hydrogen economy – fuel cells need to deliver more power in a smaller package and at much lower cost. The fuel tank needs to store hydrogen as a solid, not as compressed gas, especially for range, although carbon-fiber tanks are being used successfully to store it as a compressed gas in the meantime, but take up four to five times as much room as a conventional fuel tank. Incidentally, visions of the Hindenburg are bogus, because, in the vast majority of cases, leaking hydrogen, if lit, will burn but not explode. Where it might explode, its theoretical explosive power per unit volume of gas is 22 times weaker than that of gasoline vapor. Truth is, we learned to use gasoline; we can learn to use hydrogen too.

Progress has been made on all of these fronts. For example, improvements have been made in the energy density of the solid hydrogen fuel tank, but the weight of the tank, and the energy cost to regenerate the fuel-absorbing material, still have a long way to go. Solar cells that are optimized for direct disassociation of water are making progress, but an area equal to about half the state of Nevada is needed to make a real impact. However, there are always rooftops.

It should also be noted that direct use of fuels such as methanol, natural gas and even gasoline in an internal combustion/ electric hybrid make good sense in their own right, certainly as a stop-gap measure, rather than trying to perfect the reforming/ fuel-cell route.

Finally, there are potential ancillary benefits, such as using the fuel cell in your car to provide electricity to the grid. These benefits could be huge.

Politicians are reluctant to place too big a bet on all of the required breakthroughs and changes. So, government investment remains relatively modest, and is spread among many future energy technologies. Part of the problem, as is often the case, lies in ourselves: deviating from a proven, comfortable status quo for a new paradigm does not happen easily.

Those who say a hydrogen-based economy will never happen are just as off-base as those who are certain that it will soon be a reality. In many ways, predicting the future of invention is much like deciding whether you are an optimist or a pessimist: you simply make the choice. But achieving a hydrogen-based economy is not as daunting a task as some would have you believe. I’m hoping we get lucky.