Green Technology, Research Joint Ventures and Emissions Taxation?

This paper performs a comparison of two well known approaches for modelling R&D spillovers associated with investment in green technology, namely D?Aspremont-Jacquemin and Kamien-Muller-Zang. We show that there is little qualitative difference between the models in terms of total surplus delivered when selecting the optimal tax regime when there is pre-commitment under cooperative R&D regimes. However, under non-cooperative regimes there is marked difference, with the model of Kamien-Muller-Zang leading to higher taxation rates when firms share information. Furthermore, we argue that the Kamien-Muller-Zang model is of questionable validity when modelling R&D on emissions reducing technology due to counter intuitive results showing a positive relationship between R&D spillovers and emissions taxes.