Are clean technology and environment quality conflicting policy goals?

We analyze the effects of an environmental policy on the diffusion of a clean technology. Compared to previous articles we consider that the polluting firms are competitors on the output market and we analyze the effects of the policy on the share of adopting firms in the economy. We show that this share is not monotonic with the stringency of the environmental policy. We also compare the effects of an emission tax and tradable pollution permits and we show that, depending again on the stringency of the policy, either the tax or the permits yields a higher degree of technology adoption