Investors are constantly confronted with deciding between a multitude of different investments. The characteristics, especially the estimated return, of each alternative is never precisely known. In this paper, we propose to use fuzzy present values to model this uncertainty. We extend previous work with the possibility to account for uncertain project durations, which become increasingly important for long-term projects. The results allowed a detailed assessment of the cost of hydrogen production using a thermo-chemical cycle which is still in the early phase of research. On the theoretical side, we propose a sound fuzzification over crisp domains, avoiding in particular the unsteady behaviour of existing approaches.