Combustible hydrogène

In the 19th century, the advent of the steam engine led to a remarkable expansion of transport and industry. This steam, capable of directly supplying mechanical energy but which does not exist as such in nature – has to be produced by heating water – was, in a way, the first energy vector. Then, at the end of the same century, everything accelerated again with the advent of the internal combustion engine and electricity. The former made it possible to obtain mechanical energy from liquid fuels derived from naturally occurring petroleum. The latter, based on the properties of the constituents of matter, was a new energy vector with almost infinite possibilities, whose most advanced and promising extensions we are now familiar with through electronics and its applications. In the twentieth century, there was no human activity that was not revolutionized by the impact of these two technical revolutions. The world entered the "industrial age" and the "civilization of the automobile", both of which were responsible for profound economic and social transformations. But to fuel the extraordinary development that followed, we needed – and still need – more and more energy, which is why our planet's resources have been exploited without limit: coal, oil, natural gas, hydropower and energy from the fission of nuclear fuels. Today, we can measure the consequences of this excess: the risk of depleting fossil resources, the accumulation of nuclear waste, air pollution threatening public health and the additional greenhouse effect contributing to global warming. And yet, this energy-hungry trend continues, fuelling permanent growth that goes hand in hand with the emergence of developing countries and the increase in the world's population. It is thus foreseeable that, compared with 1970, energy requirements will double by 2020 and triple by 2050. To resolve this contradiction between the growing need for energy, the depletion of fossil fuels, the additional greenhouse effect and pollution, several solutions are possible at the same time:

• reduce energy consumption through "rational use" actions;

• reduce pollution and greenhouse gas emissions by using more appropriate fuels;

• pursue the use of nuclear energy, hoping one day to achieve fusion, which at present is a scientific gamble;

• use so-called renewable energies: wind, solar, hydraulic, biomass, geothermal ;

• use hydrogen, a clean, storable energy source.

Hydrogen is a non-toxic, high-energy gas. It can produce heat by direct combustion, with water as a by-product, but it can also produce electricity and heat in fuel cells, again with water as a by-product. Until...