The Science issue for August 13 2004 includes a special section "Toward a Hydrogen Economy". I was tempted to call it "The Hydrogen Mirage", until I saw the story in the New York Times (11/11/04) about a gas station that actually dispenses both liquid and gaseous hydrogen to the six GM cars that can run on it. (There are now about 70 prototype vehicles worldwide.)
The introduction is entitled "Not so Simple", which makes it self-explanatory. It is followed by four News articles, a "Review", which is the heart and the most interesting part of the section, and two "Viewpoints".
The first piece is called "The Hydrogen Backlash". It describes one of the GM minivans that run on fuel cells, and goes on to say that "current hydrogen programs fall pitifully short".
It describes, although not as clearly as I would have liked to see it, that hydrogen is not a primary fuel, but rather an energy carrier, like an energy distribution system. It is a storage system, like a battery. If fossil fuels are used to produce the hydrogen, either by electrolysis or from natural gas, that only shifts the accompanying CO2 emission and other pollution from the point of use, as is true for the generation of electricity. At present using natural gas is the cheapest way to get hydrogen, at about $5.- for the equivalent of a gallon of gasoline. As for other processes "years of research...have yet to yield decisive progress." The necessary storage volume will be four to eight times as large as for gasoline.
The second article is called : "The Carbon Conundrum". "Coal is not going away", and the "sequestration" of CO2 may give us "time to develop 22nd century energy sources." Next, "Fire and ICE" refers to one of the large number of maddening acronyms (Internal Combustion Engine). Fuel cells may come eventually, but ICE is here.
"Will the Future Dawn in the North" talks about Iceland, where geothermal and hydroelectric sources could bring energy independence. Today it still imports 30% of its energy as oil for transportation. Three fuel cell buses point to the future. There is also the tantalizing suggestion that this model shows that the developing world may be able to skip the petroleum era altogether.
S. Pacala and R. Socolow of Princeton University have the major and the most hopeful contribution: "Stabilization Wedges: Solving the Climate Problem for the next 50 Years with Current Technologies." It considers only the problem of CO2 emissions, and contrasts the probably disastrous "BAU" (business-as-usual) with 15 "wedge" options, which, in some combination, can see us through the next half century.
There are several categories, with "Efficiency and Conservation" ranking first. Improved fuel economy, reduced reliance on cars, more efficient buildings, and improved power-plant efficiency could take care of about half of what is needed. The second category, "Decarbonization", includes substituting natural gas for coal, carbon sequestration, fission, wind, photovoltaic, and biomass energy. Finally, the natural CO2 sinks of forests and agricultural soils could be enhanced. The authors end by saying that "none of the options is a pipe dream or an unproven idea...Every one of these options is already implemented at an industrial scale and could be scaled up further over 50 years".
Next come the two Viewpoints. The first, "Sustainable Hydrogen Production", by John A. Turner, goes into some detail on hydrogen production, putting it into the 75 to 100 year time frame.
Finally, "Hybrid Cars Now, Fuel Cell Cars Later", by N. Demirdoven and John Deutch, comes to the conclusion that fuel cell cars are not likely to be more efficient than hybrid cars, which makes me wonder why they would even be an option "later". They strongly advocate that present hybrid technology be expanded.
Together these articles deal with much more than a futuristic hydrogen economy. They go into quantitative detail on the various alternatives. They leave us with the positive and hopeful outlook that we can use present technologies wisely, and prepare for the future that is to follow.