The energy production and consumption is a major contributor to our environmental problems. The energy carrier hydrogen can be a part of the solution. In the thesis the Bellona Foundation’s role in the process of technical change towards utilisation of hydrogen in Norway is investigated. Its role is analysed through the concept of mediation, which is based on seeing technical change as a social process.Mediators connect, or build bridges between, different actors, as well as between different types of knowledge. They establish new kinds of links and create new arenas of interaction for previously separated units. In addition, or through their work, they translate knowledge from one context or domain to another. They are also processing, interpreting and combining knowledge in new ways. Mediators bring together people with different competencies, and orchestrate their efforts often on a consensus basis.Bellona combines the different kinds of mediations, to influence the process of technical change at various levels and steps. They mediate mainly within the industry and between the industrial- and governmental domain. To some degree they also mediate between the experts and the public. But the direct contact with the public seems to be more or less absent in their hydrogen work.It seems like Bellona’s mediator role fills an open space in the realm of technology policy making. Environmental oriented NGOs will perform or combine various mediating roles differently. To be able to make socially appropriate and sustainable technical change, probably other actors than the established traditional ones should be more involved. The possibilities for public participation should be strengthened, as well as the possibilities for mediation.