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Hydrogen utilization dangerous for climate?
Wishful thinking instead of sound analysis
Hydrogen is a clean fuel. Its use is not associated with local emissions like carbon dioxide, soot, methane, other hydrocarbons, etc. But could its large scale use, together with corresponding releases to the atmosphere, somehow harm the environment in an indirect way? Indeed, is the message of a paper in the acknowledged Science magazine (Tromp et al., 300 (2003) 1740ff). The authors assume that all processes based on fossil fuels will be replaced by ones using hydrogen, combine this with assumptions about the release of hydrogen to the atmosphere by leaks and other losses, and calculate values for the concentration of hydrogen near the earth surface. Using methods from climate research they find that this would enhance the water content of the stratosphere, which in turn would cool the latter and slow down the closing of the ozone holes. There is no discussion that every fuel must be investigated for its complete ecological impact. Unfortunately DWV finds that this has not been done in a sound way in the Science paper mentioned. Here a few detail comments:
- Hydrogen technology has been here for more than a century, namely in the chemical industry. The amounts associated with the energetic use of hydrogen will for many years remain below those generated and consumed in the industry. So why do we not find the predicted concentrations now? It is neither likely nor even desirable that all fossil fuels will be simply replaced by hydrogen. Direct use of sustainable energy and new processes with higher efficiency would in many cases eliminate the need for a fuel like hydrogen. Combustion of fossil fuels leads to the generation of hydrogen as well. One source is the photochemical decomposition of methane (natural gas) released to the atmosphere, another are reactions of carbon monoxide generated in incomplete combustions with water. Direct use of hydrogen would eliminate these sources. Losses of 10 to 20 % in handling hydrogen are taken from thin air, both for present and for future applications. The literature given as proof has been quoted in a distorted way; sometimes the sources say rather the contrary of what they are used for.
- The conclusion from the (doubtful) emissions to the concentrations in the atmosphere is simplistic and thus unfounded. The authors admit that a number of other important factors have not been taken into account, such as the decomposition rates which increase with emission, the hydrogen intake of the soil, and other atmospheric processes.
A more detailed analysis of the paper mentioned above can be found on the website of our member company L-B-Systemtechnik GmbH (www.hyweb.de). But the above comments do show that the paper is no useful contribution to scientific discussion. We hear that a comment on this will appear in the next issue of Science. DWV regrets that a chance has been wasted. It remains a fact that neither science nor general reason contradict these fundamental statements:
- Decreasing our energy consumption, starting with the biggest consumers, enhancing efficiencies, and above all the transition from fossil fuels to renewable primary energies are mandatory for securing our future. Hydrogen offers a means to store and transport energy wherever this can not be done using electricity. The latter will remain our most important energy for the foreseeable future. Hydrogen is clean and safe.
- Fuel cells are not only clean and quiet, but their high efficiency contributes to the reasonable use of our resources.
The obstacles on the way to hydrogen energy are mainly economical and political in nature, not scientific or technical.
Published by the German Hydrogen and Fuel Cell Association (DWV), Berlin
V. i. S. d. P.: Dr. Ulrich Schmidtchen, Berlin
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16 June 2003
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