Typical of the present high standard energy supply systems is stored primary energy and the technical dominance of thermodynamic cycle processes to render high value energy performance for mobility, mechanical power and electricity. Hydrogen plays a key role in the necessary energy transition. Hydrogen fuel basically allows the use of present technical appliances to be maintained without the emission problem. The energy performance industry should act as mediator in the preparation for the transition process. In this sense the two utilities HEW (Hamburger Elektrizitätswerke) and HGW (Hamburger Gaswerke) contribute with various activities to the development of future hydrogen energy use. The existing HGW filling station for natural gas for its own and for public use will be extended by another unit for hydrogen fuel. This gas filling station is part of a project which intends to supply hydrogen, originating from hydropower in Iceland and delivered by ship to private company cars. The filling stations are being officially calibrated in order to supply fuel to the public. Because of the number of people involved the demonstration of hydrogen fuel may be even more effective in city buses. Also the influence of the higher fuel costs is relatively low compared to the other high cost figures. A changeover to hydrogen operation would cost about 12 DM/km m (+ 150 %), mainly because of the more than twofold cost for the hydrogen bus. In the years 1989/91 the project EQHHPP visualized Hamburg as being the receiving point of about 15,000 t/a of liquid hydrogen originating from 100 MW electrical hydropower in Canada. The study investigates applications in Hamburg like in city buses, in a demonstration aircraft and for heat/ electricity cogeneration plants. Research work covers the safety of hydrogen cargo tankers and questions of landing and distribution of hydrogen. Special electrolyzers, affordable short-term storage, the adequate degree of decentralization of filling stations and the whole user structure has to develop. The electrolyzer is the key component of a new power regulating system operated on the existing electrical grid. In many cases power grid regulation with electrolyzer allows the optimisation of power production.