Hydrogen Economy

The term of hydrogen economy is used to evoke hypothetical a future company in which hydrogen (H₂) would be used to store energy for all the portable applications (primarily the car) and stationary distributed, following the example oil today.

Why hydrogen

Hydrogen causes many hopes in the current context, where one becomes aware of the need for finding alternatives to the consumption of fossil energies, and where one wonders about the local pollution of the vehicles. The principal asset of hydrogen is its capacity to produce energy, and in particular of electricity. One uses it by combustion, in a thermal engine to produce movement directly, or in a Combustible battery to obtain electricity. The energetic efficiencies obtained are good, about 60% for certain piles. Moreover, this combustion is clean, it rejects only water. One thinks then immediately of the car, which requires too much energy so that it is stored in batteries, and which one seeks to decrease the harmful emissions. Hydrogen makes it possible to consider a vehicle completely not pollutant, with important autonomy, and the interesting energetic efficiency. As one can moreover produce it by Hydrolyze with electricity, one can then design a whole clean die to feed the vehicles. From where the term of hydrogen economy.

First prospect: localized production

A first way of producing hydrogen is to obtain it by fossil or vegetable fuel combustion: of ethanol, coal or hydrocarbons. This is possible in a located way, in a car for example. The energetic efficiencies obtained are rather interesting. Hydrogen is not whereas an intermediary enters the thermal engine producing it and the combustible battery, producing the electricity itself used by an electrical motor. This structure can seem completely useless compared to the spark-ignition engine, directly producing the kinetic energy starting from the fuel; by comparing the energetic efficiencies of these two solutions, one realizes that the hydrogen solution is a realistic alternative. The energetic efficiency of the pair production of hydrogen-pile with fuel is comparable with that of the spark-ignition engine, and the losses on the level of the electrical motor are quasi null. Moreover, the use of the electric intermediary makes it possible to consider energy saving by recovery to braking, and for the embarked equipment: part of the energy of the engine is retransformée today in electricity, which involves other losses. Electricity would be directly available in the combustible battery engine. Another optimistic raison d'être, the spark-ignition engine is a very tested technology, whose output is optimized since decades by all auto industry, whereas the vehicle with hydrogen was only studied much less. One thus thinks that progress to be made are still much more important in this die.

Hydrogen economy

However, this embarked production does not solve the problem of the consumption of fossil energies, and embarked pollution. The partisans of the hydrogen economy go much further, and preach a production with large scales in factory, then a die of provisioning to store it aboard vehicle.

Production with large scales

Currently, one produces hydrogen machines some by two processes mainly.

More used remains the combustion of fuels, hydrocarbons or coal. It is currently the most economic solution, and that offering the best energetic efficiency. Nevertheless, this solution does nothing but defer the problem of the consumption of fossil energies. The other solution implemented at large scales is the electrolysis of water. It is much more expensive and offers an output weaker than the solution stated higher. But since it consumes only electricity, and that one can produce electricity properly, it makes it possible to consider an entirely clean die.

The principal objection is that if one can produce electricity properly, production capacities by ecological means remain limited. To conceive thus a whole economy entirely on electricity would amount multiplying consumption of it, which could be done only by the nuclear power and the thermo plants. One returns from there finally to a polluting die.

Certain solutions are currently being studied, such as nuclear plants producing in parallel electricity and hydrogen, but remain in an embryonic state as the project VHTR which considers the fuel hytane diffusion by Gazoduc S.

A last solution would be to produce hydrogen with wind mills. Entirely clean but very expensive solution.

Only Iceland undertakes to produce hydrogen with large scales by using the Géothermie which is an entirely clean solution.

Iceland will become a country pioneer in the mass production.

Question of storage and transport

The question of storage: far from dense, hydrogen must be compressed with very important pressures to be transportable in a reasonable volume. In addition to the security issues which it comprises, this compression requires much energy. Other solutions are considered but not controlled for the moment; storage in liquid form at very low temperature is considered, but not controlled on board a vehicle. A solution raises hope, even if for the moment it remains with the state of fundamental study: the " piégeage" hydrogen by carbon.

Transport: it would be necessary to set up gigantic infrastructures to produce and transport hydrogen through the territory. It is about an effort comparable with the development of the dies of distribution of the oil, which asked for several tens of years. The cost of the deployment of a complete system of distribution could require from 10 to 15 billion dollars for the only United States. This economic brake implies that the passage to hydrogen can result only from one generalized choice, and thus requires the flattening of all the existing difficulties

Conclusion

If the hydrogen economy is for the moment a remote prospect, even straightforwardly a fantastic notion, certain less ambitious applications could be born in a future much nearer, such as combustible batteries running on ethanol for portables in the place of the batteries, with a considerable profit of autonomy.

However, although imperfect and far from being at the point, the solution of hydrogen is one of only which can currently answer the question: " how to maintain our lifestyle without oil? ". If this theory thus has what to allure, the skeptics, such as holding of the Décroissance, recall that the end of oil is envisaged in the next decades; it would be thus be likely to believe blindly in this solution, of which one will perhaps not know viability before several tens of years. The prospect for a hydrogen economy should not thus make us lose sight of the fact the need for launching out as of today in an important reduction of our energy consumptions.

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