The paper studies the use of emission taxes and feed-in subsidies for the regulation of a monopoly that can produce the same good with a technology that employs a polluting input and a clean technology. In the first part of the paper, we show that the efficient solution can be implemented combining a tax on emissions and a subsidy on clean output. The tax is lower than the environmental damages, and the subsidy is equal to the difference between the price and the marginal revenue. In the second part of the paper, the second-best tax and subsidy are also calculated solving a two-stage policy game between the regulator and the monopoly with the regulator acting as the leader of the game. We find that the second-best tax rate can be the Pigouvian tax, but only if the marginal costs of the clean technology are constant. Using a linear–quadratic specification of the model, we show that the clean output is larger when a feed-in subsidy is used than when the tax is applied, but the dirty output can be larger or lower depending on the magnitude of marginal costs of the clean technology and marginal damages. The same occurs for the net social welfare, although we find that for low enough marginal costs of the clean technology, the net social welfare is larger when a feed-in subsidy is used to promote clean output regardless the importance of the marginal damages.

本文研究了使用排放税和上网电价补贴来监管垄断的情况，这种垄断可以通过采用污染输入和清洁技术的技术来生产相同的商品。在本文的第一部分中，我们表明可以结合排放税和清洁输出补贴来实施有效的解决方案。税收低于环境损害，补贴等于价格与边际收益之差。在本文的第二部分中，还计算了次优税收和补贴，解决了监管者与垄断者之间的两阶段政策博弈，其中监管者充当博弈的领导者。我们发现，仅在清洁技术的边际成本不变的情况下，第二高的税率可以是庇古税。使用该模型的线性二次方规范，我们表明，使用上网补贴时的清洁产出要比征税时的清洁产出更大，但脏污产出可以更大或更小，具体取决于企业边际成本的大小。清洁技术和边际损害。净社会福利也会发生同样的情况，尽管我们发现，对于清洁技术的足够低的边际成本，当使用边际补贴来促进清洁产出时，无论边际损害的重要性如何，净社会福利都会更大。