A Franco-British publication contradicts American works published in 2003, in which such a transition would present a danger to the stratospheric ozone layer.
At maturity of a few decades, the depletion of fossil fuels, such as their impact on climate, should force manufacturers to find energy alternatives to oil, coal and natural gas.
The hydrogen through the fuel cell - which produces electricity and water from hydrogen and oxygen - is the alternative around which the broadest consensus has formed.
However, the climate impact of an economy based on this alternative energy is still debated.
According to a Franco-British study recently published by the Geophysical Research Letters, such a "hydrogen economy" would have little impact on the chemical equilibrium of the Earth's atmosphere. While they do not conflict with the consensus that has emerged around hydrogen as an energy alternative to oil, these results contradict work previously conducted by US researchers (Le Monde du 16 juin 2003).
In June 2003, the journal Science has published the findings of a simulation conducted by researchers at the Jet Propulsion Laboratory and the California Institute of Technology, in which the replacement of fossil fuels with hydrogen significantly degrade the layer stratospheric ozone.
The principle of the fuel cell was not challenged. But given the imperfections of production and delivery technologies light gases, the authors of the study assumed a loss of 10% to 20% of the hydrogen used in place of fossil fuels. The amounts of hydrogen and released into the atmosphere would represent between 60 and 120 million tonnes.
The authors of the study published by Science, such contributions would upset the chemical balance of the upper layers of the atmosphere, contributing to an increase in the concentration of stratospheric water vapor and cooling the higher regions of the terrestrial sky . Hence the reactions of transformation of inactive brominated and chlorinated compounds, molecules harmful to the ozone.
The publication of this work has caused controversy. The journal Science published in October 2003, several scientific correspondence calling to consider the results of this simulation with caution and criticizing the hypothesis of a leak rate between 10 20% and%.
Source: BBC, May 2004
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