Storm Watch

I found your editorial and articles on storm forecasting [“Modeling Toward Accurate Storm Forecasting,” and “It’s Hurricane Season: Do You Know Where Your Storm Is?” [August] very interesting. For a lot of weather forecasting, it’s a lack of data that limits accuracy more so than computing power. The hurricane article says, “Three things are going to foment this revolution in forecasting accuracy: supercomputers, satellites, and advances in the scientific understanding of how weather evolves.” More and improved data from aircraft sensors should also be listed here.

In the IEEE Spectrum’s June issue, [“ Troubled Weather Satellite Program,” News], I see that the estimated cost for the NPOESS satellite program has gone from $6.5 billion to more than $10 billion. Although they may be useful for hurricane forecasting, for everyday forecasting the return on investment for some of them is questionable. Sensors on aircraft, especially turboprops flying in the lower troposphere, are much cheaper to operate and give more accurate four-dimensional real-time data where it’s really needed.

Our company, AirDat, is deploying a sensor that measures winds, humidity, temperature, turbulence, and icing. Our TAMDAR sensor is currently installed and operating on the Mesaba turboprop fleet, which operates in the Great Lakes region. Its data has proven very useful to forecasters in making more accurate model predictions.

Daniel Mulally

IEEE Member

Evergreen, Colo.

The Hydrogen Economy

The item “Hydrogen on Track” [News, August] reported on some encouraging developments in mobile applications of fuel cells and wisely referred to the technology as hydrogen-fuel-cell propulsion. In the general debate on alternative fuels, one very simple and basic factor should always be borne in mind with regard to hydrogen, but it is all too frequently forgotten. Where does the hydrogen come from?

This confusion is exemplified in the article: “…railroads around the world are taking a serious look at alternatives to diesel because of skyrocketing fuel costs.” But to what extent is hydrogen, as such, an alternative? Hydrogen is highly reactive and all too anxious to oxidize. The only possible source of hydrogen as a primary fuel to replace oil and natural gas would be in the form of mineral hydrides. These are far too rare to be considered worth exploiting.

The most abundant source of hydrogen is water, hydrogen oxide. We have two ways of “de-oxidizing” the hydrogen (reducing the water), electrolysis and the most widely used method of producing hydrogen commercially, reduction with carbon. If all were perfect (which it never is), it would require exactly the same amount of energy to release a given mass of hydrogen from water as it would to oxidize that mass of hydrogen back to water in a fuel cell. The net energy produced is thus zero, and the hydrogen is simply an intermediate energy carrier for moving the point of use from one place to another—in the same way as electricity.

Reducing water to hydrogen with carbon produces carbon dioxide. Generating electricity for electrolysis usually produces carbon dioxide (from coal, oil, or gas). So the use of hydrogen fuel does not directly reduce the carbon dioxide footprint of the energy consumption in any way whatsoever, except insofar as the overall efficiency of the reduction-oxidation-consumption process is higher than that of other prime movers.

The key factor in the fuel-cell technology is the potential to reach much higher efficiencies than are possible with mobile internal combustion engines. As things stand, it appears that we can look for an efficiency savings of 2:1, halving the primary fuel consumption and the carbon dioxide footprint. Modifying internal combustion systems to approach the efficiency of fuel cells makes them unwieldy in both price and bulk, so the fuel-cell approach is clearly one that should be energetically explored.

As to alternatives to diesel, the use of the hydrogen intermediate enables us to use any primary energy source that may be available as an alternative to fossil fuel. The implication here, however, is that we need to convert our power stations to nonfossil fuel, generate more power from “renewable” sources (solar, wind, hydro, tidal, and so on) and use nonfossil carbon to produce hydrogen by thermochemical reduction. Oh, and by the way, dams are bad for the carbon cycle; they impair the deep ocean sequestration of carbon dioxide. So hydro, yes, but no more dams, please.

Peter Bissmire

Associate Member

Caerphilly, Wales

I read with interest about the new technologies in hydrogen-powered trains. As an engineer in traction power at Los Angeles Metro, I have seen many new technologies perform energy savings, and I wonder whether this new hydrogen methodology will take hold on TP substations as well.

I was talking with a manufacturer about a battery substation to collect energy from regenerative braking and prove voltage support and power support. I also discussed (with a manufacturer who already does what you say for windmill applications) an idea of using wayside fuel cells and doing what you indicate on the train by producing hydrogen by electrolysis.

Would it be better to apply this fuel-cell technology as a substation replacement system or addition, instead of using high-voltage power utilities, by providing gas to a fuel-cell substation rather than putting it on a train? Is this industry application coming soon?

Thomas Langer

IEEE Member

Burbank, Calif.

I am insulted by the news item on the “hydrogen-powered locomotive“ [August]. It indicated that in case of some natural disaster, such as Hurricane Katrina, you could just “drive it to wherever you need it, hook it up, and provide enough power....” Hook it up to what—your friendly neighborhood hydrogen fuel station? Not in Metairie or New Orleans. Nor in my town, nor yours.

If this thing can run at 1200 kilowatts output, it will need a lot of hydrogen, not easy for your neighborhood station to provide. And that “station” would need an input of several megawatts to generate that much hydrogen. I don’t know anybody who says that generating H2 is efficient or cheap. The caption on a photo says this machine can keep the lights on at a military base or hospital. Fine concept; now show me a military base (or hospital) that has a neighborhood hydrogen station. If you can’t run a hose over to such a station, this quickly turns into “The Little Engine That Couldn’t.”

The author quotes “experts” as saying that “railroads...are taking a serious look at alternatives to diesel because of skyrocketing fuel costs.” The next time you drop by your “friendly neighborhood hydrogen station,” check out the price of hydrogen. (That is a joke, because nobody—except maybe NASA—has one of them.) If somebody is not holding his thumb on the scale, you would see that the price of hydrogen will rise and fall just like the price of any other fuel, because energy is not cheap if it has to be generated by electricity or by fuels that compete in an open market.

I am not opposed to subsidies for experimental applications of energy, but somebody has to get serious about large-scale practical considerations. Hydrogen is not cheap and will not be cheap. Anybody who implies that it is, is being fooled by the same pseudoscientists who think that “hydrogen is cheap because water is plentiful.”

And if you want to ignore the minor purchase price of a new locomotive with fuel cells, and the little cost of its fuel, check out the recurring price of replacing the fuel cells when they poop out in a few months. Finite lifetime. That alone makes this an expensive proposition that could be cost-effective only on a NASA railroad on Mars.

I am sure the “fuel-cell locomotive” is an excellent piece of engineering, allowing for the minor little problems I have pointed out. It’s just the fuel-cell cost, and the hydrogen supplies, that are minor little problems. These problems were ignored in that article.

Robert A. Pease

IEEE Member

San Francisco

The author replies: The writer makes a valid point that we should have said more about how hydrogen will be carried onboard locomotives. In the mine locomotive described, the hydrogen is stored chemically as solid metal hydrides. Other proposed trains could carry their fuel either in metal-hydride form or as compressed gas, and be refueled at stations placed where hydrogen can be piped in or manufactured on-site.

For example, the Charlotte-Mooresville line mentioned in the article runs within a few kilometers of a colocated hydroelectric generating facility and a nuclear power plant. The plant’s electricity already powers a scrap iron smelting facility located a stone’s throw from the train tracks. A refueling station there would never want for electrolysis hydrogen. In an emergency, the military yard switcher-cum-generator would not rely on a local hydrogen refueling station. Once it reaches its destination and is linked to, say, a hospital’s electrical connection, it becomes, in essence, a stationary power plant to which hydrogen can be delivered by truck in high-pressure tanks.