Policies to reduce greenhouse gas emissions from transportation fuels often take the form of renewable fuel mandates rather than taxes or cap-and-trade programs. Delays in the development and deployment of new technologies when binding mandates exist for their use may lead to situations with high compliance costs. We study the effects and efficiency of two mandates, a renewable share mandate and a carbon intensity standard, with and without a cost containment mechanism. Using both a theoretical model of a regulated fuel industry and a numerical model of the U.S. fuel market, we show that cost containment mechanisms can have the benefit of both constraining compliance costs and limiting deadweight loss. According to our numerical results, an optimally set mandate alone leads to only modest gains over business as usual welfare levels. The efficiency of both policies, especially carbon intensity standards, can increase substantially when combined with a cost containment mechanism.

减少运输燃料产生的温室气体排放的政策通常采取可再生燃料强制性形式，而不是税收或总量控制与交易计划。当存在具有约束力的强制要求使用新技术时，新技术的开发和部署被延迟，可能会导致合规成本高昂的情况。我们研究了两种强制性措施的效果和效率，可再生能源共享性强制性措施和碳强度标准，有无成本约束机制。使用受管制的燃料行业的理论模型和美国燃料市场的数值模型，我们表明成本控制机制可以既具有约束合规成本又可以限制无谓损失的好处。根据我们的数值结果，仅以最佳方式设置任务授权只会比常规的福利水平获得适度的收益。