9. Conclusions and outlook

If fuel cell systems are now beginning to be well mastered, this is the fruit of intense research into all the elements of these systems over many years: the fuel cell itself, of course, but also all its auxiliaries considered individually. However, the aim is not to find an optimum sub-system by sub-system, but rather a global optimum within such a fuel cell system, which is never (unfortunately) the sum of its local optima. The objectives sought in such a global optimum on the scale of the fuel cell system are manifold: energy efficiency, compactness, static and dynamic performance, durability, maintainability, lowest possible acquisition and operating costs, recyclability, etc. Compromises therefore have to be made in order to achieve these objectives. Compromises therefore have to be made.

The level of development of these fuel cell systems means that a wide...