Entry, location, and optimal environmental policies

We investigate the problem of choosing environmental regulations to control a multilateral, spatially heterogeneous pollution externality. There are three sources of inefficiency in this problem; the number of firms, their locations and their production/emissions levels. A first-best policy requires three instruments to address each of the sources of inefficiency, but such policies are not practical in most settings. Therefore, we examine the relative performance of second-best policies that optimally control one or two of the sources of inefficiency while leaving the other one or two sources uncontrolled. Because of the complexity of our theoretical model, we conduct numerical simulations to compare the alternative policies. We find that a policy of optimally-chosen individual quotas by themselves perform very poorly, because they encourage excessive entry. Combining individual quotas with an optimal entry restriction performs significantly better. Spatially differentiated taxes alone perform very well, because they partially address both the entry and location sources of inefficiency in addition to limiting pollution. We also argue that the welfare losses associated with even simpler policies like zoning restrictions or homogeneous taxes may not be high enough to justify the additional implementation difficulties associated with theoretically more efficient policies.