Major system components of possible future energy supply based on hydrogen generated by utilizing (solar) energy unaccompanied by release of carbon dioxide are installed on an industrial scale at a demonstration facility located in Neunburg vorm Wald, Germany. Initial technical aspects of stepwise transition from present-day energy supply aligned primarily to fossil fuels are considered. Most of the plant subsystems constitute prototypes of innovative technologies. Among others, the facility comprises: photovoltaic solar generators, water electrolyzers, catalytic and advanced conventional heating boilers, a catalytically heated absorption-type refrigeration unit, fuel cell plants for stationary and mobile application, and an automated LH2 filling station for test vehicles. Focal points of the investigations being carried out under the project are performance of the plant subsystems and their interaction under practical operating conditions. Analysis of the work is yielding a reliable database for updated assessment of the prospects and challenges of (solar) hydrogen technology. The present review (current to October 1997) concerns primarily the technology and operation of the facility with regard to the objectives and perspectives of the project. Results of the test programs are not reported in explicit detail; rather, they are communicated by integrating them into the more practical records of overall plant operation.