In socio-economics it is well known, that the success of an innovation process not only depends upon the technological innovation itself or the improvement of economic and institutional system boundaries, but also on the public acceptance of the innovation. The public acceptance can, as seen with genetic engineering for agriculture, be an obstacle for the development and introduction of a new and innovative idea. In respect to hydrogen technologies this means, that the investigation, compilation and communication of scientific risk assessments are not sufficient to enhance or generate public acceptance. Moreover, psychological, social and cultural aspects of risk perception have to be considered when introducing new technologies. Especially trust and familiarity play an important role for risk perception and thus public acceptance of new technologies.