Major system components of possible future energy supply based on hydrogen generated by utilising solar energy have been installed on an industrial scale at Neunburg vorm Wald, Germany. Consideration is given to the initial technical aspects of stepwise transition from present-day energy supply aligned primarily to fossil fuels. Focal points of the investigations being carried out under the project are performance of the plant subsystems, most of which constitute prototypes of innovative technologies, and their interaction under practical operation conditions. Analysis of the work has yielded a reliable data base for updated assessment of thee prospects a nd challenges of solar hydrogen technology. The present review (current to April 1996) centres on the technology and operation of the facility with regard to the objectives and perspectives of the project.