Market Power in Coal Shipping and Implications for U.S. Climate Policy
中文摘要
经济学家普遍赞同对二氧化碳排放定价，以内部化与气候变化相关的外部性。这样做将显著影响碳密集度最高的能源——煤炭。然而，美国煤炭市场还存在另一种扭曲：将煤炭运输至发电厂的铁路公司能够行使市场势力。本文估计铁路煤炭运输加价如何响应煤炭需求的变化。我同时运用简化式方法和结构方法，识别一个主要中间品市场中的加价。研究发现，当作为竞争性燃料的天然气价格下降导致下游发电厂需求发生变化时，铁路承运商会降低煤炭运输加价。研究结果表明，与加价保持不变的反事实情形相比，煤炭运输加价下降使美国近期的气候损害增加了119亿美元。不完全传导可能会削弱增量碳税的环境效益，并将税负转向上游铁路公司。尽管如此，幅度不可忽略的碳税仍可能提高福利。
Abstract
Abstract Economists have widely endorsed pricing CO2 emissions to internalize climate change-related externalities. Doing so would significantly affect coal, the most carbon-intensive energy source. However, U.S. coal markets exhibit an additional distortion: the railroads that transport coal to power plants can exert market power. This article estimates how coal-by-rail markups respond to changes in coal demand. I identify markups in a major intermediate goods market using both reduced-form and structural methods. I find that rail carriers reduce coal markups when downstream power plant demand changes due to a drop in the price of natural gas (a competing fuel). My results imply that decreases in coal markups have increased recent U.S. climate damages by $11.9 billion, compared to a counterfactual where markups did not change. Incomplete pass-through would likely erode the environmental benefits of an incremental carbon tax, shifting the tax burden towards upstream railroads. Still, a non-trivial tax would likely increase welfare.