Technological options can be regarded as variations in an evolutionary development process. The variations are put forward by their respective technological communities and are selected by technology selectors. Building on the notion of quasi-evolutionary technology development we show how technological communities secure their position on R&D agendas through feeding and maintaining expectations in arenas of expectations. We examine this process by studying the expectations work of the community that tries to develop metal hydrides for the on-board storage of hydrogen for mobile applications. Metal hydrides are proposed as a promising alternative to gaseous and liquid hydrogen storage but are yet underdeveloped. Its proponents however, succeed in convincing their sponsors of the future potential of metal hydrides. In this paper we show how expectations of this technological option are raised and maintained by its developers and how this has kept them on hydrogen technology agendas for over 40 years.
