'The economic effects of environmental taxes depend on the market structure. Under imperfect competition with free entry and exit, environmental taxes have an impact on economies of scale by changing the number and size of firms. Whether economies of scale rise or fall in a particular industry depends on induced changes in the price elasticity of demand. Because export demand is more price elastic than domestic demand, the overall price elasticity rises (falls) as the industry gains (loses) in comparative advantage. We use a computable general equilibrium model for Germany to examine the effects of a unilaterally introduced carbon tax under both perfect and imperfect competition. Our key finding is that induced structural change in favor of...