The paper looks at a model of directed technical change in an environmental-economics context. Firms can do conventional or "green" R&D or they can abate emissions at the end of pipe. The paper has two main foci. On the one hand, it investigates the impact of environmental regulation on the...

Since governments can influence the demand for a new abatement technology through their environmental policy, they may be able to expropriate innovations in new abatement technology ex post. This suggests that incentives for environmental R&D may be lower than the incentives for market goods...

We examine the impact of an optimal emissions tax on research and development of emission reducing green technology (E-R&D) in the presence of R&D spillovers. We show that the size and effectiveness of the optimal emissions tax depends on the type of the R&D spillover: input or output spillover....