HyWays aims to develop a validated and well-accepted roadmap for the introduction of hydrogen in the European energy system until 2030 and provides an outlook to 2050. The Roadmap will reflect real life conditions by considering technological as well as institutional, geographic and socio/economic barriers and opportunities at country specific level. Mobile and stationary applications are addressed, including possible synergies between the two. The final European roadmap will be presented in mid 2007 substantiating from a synthesis process incorporating visions and roadmaps for the 10 participating countries (Finland, France, Germany, Greece, Italy, the Netherlands, Norway, Poland, Spain and the UK). One important element of this roadmap is the hydrogen fuelling infrastructure build-up. The HyWays infrastructure analysis comprises an assessment of the expected hydrogen demand development for transportation and stationary use as well as the required hydrogen production, transport and distribution system. Various stakeholders from industry, politics and research institutes have been engaged in intense discussions at a technical level and within each of the 10 countries. The discussions were supported by the use of simulation and software tools for (a) the geographical allocation of hydrogen demand and (b) the optimized employment of resources over time. Besides economics also qualitative issues (e.g. safety, location-specific appropriateness, risk) were considered for the infrastructure build-up. The analysis has shown that the hydrogen production infrastructure build-up strongly depends on regional particularities, such as the primary energy envisioned for hydrogen provision, population density and geographic factors such as topography and proximity of neighboring population centers. The infrastructure analysis also reveals that an inter-regional discussion is necessary as economic synergies can be exploited. These would remain untapped if the infrastructure build-up would only result from intra-regional considerations. Different technical approaches from on-site hydrogen provision to central supply schemes as well as home-refueling, will all play their role during the transition phase. In less populated regions and those with difficult topology (e.g. mountainous landscape in Norway; archipelago in Greece) will tend towards a dispersed supply whereas densely populated areas or those with an existing road, rail or gas pipeline network will tend towards central supply once a mass market is established. Furthermore, the analysis shows that also for the early introduction phase decentral solutions seem to be favorable continuing into the transition phase if energy prices should rise decisively. The known problem of high initial investment in infrastructure can be mitigated with a staged local build-up; use of hydrogen should be initiated in the most beneficial locations (e.g. population centres) and, with a continuously increasing penetration of the energy system, gradually expand towards locations difficult to supply.