Optimal growth with pollution : how to use pollution permits ?.

We study optimal growth and its decentralization in an overlapping generations model. The decentralization of an optimal path needs some specific taxes in addition to lump-sum transfers if there are externalities. The introduction of market of permits allows neutralizing the external environmental effects. We shows that there is a unique management of permits such that the equilibrium coincides with the optimal path : all permits should be auctioned i.e. no permits to firms. This conclusion is in contradiction with the usual pratice of grandfathering.