Short-Run Price and Welfare Impacts of Federal Ethanol Policies
构建美国玉米、乙醇和汽油市场的短期随机结构模型，评估三项联邦乙醇政策对价格和福利的影响，发现政策变动对玉米价格影响有限但分配效应显著。
High commodity prices have increased interest in the impacts of federal ethanol policies. We present a stochastic, short-run structural model of U.S. corn, ethanol, and gasoline markets to estimate the price and welfare impacts of alternative policies on producers and consumers of corn, ethanol, and gasoline. The three federal policies that we consider are the Renewable Fuels Standard, the blenders tax credit, and the tariff on imported ethanol. Our model examines the impact of these policies on prices during the 2008/09 marketing year. Our results show that in the short run, a change in U.S. ethanol policies would not have a large, immediate impact on corn prices. Eliminating any one of the policies would reduce average corn prices by less than 4%. Removal of all three programs would decrease average corn prices by 14.5%. The reason why the changes are relatively modest is that existing U.S. ethanol plants will only shut down if their variable cost of production is not covered. Changes in ethanol policies would have large distributional impacts. Corn growers, ethanol producers, and fuel consumers have a large incentive to maintain high ethanol consumption. Gasoline producers have a large incentive to reduce ethanol production and imports. Livestock producers have a large short-run incentive to reduce domestic ethanol production.