Monday, 19 March 2007

Future Impacts of Coal Distribution Constraints in a Coal-to-Hydrogen Economy

David McCollum and Joan Ogden. University of California-Davis

After years of relatively slow growth, coal is undergoing a renaissance. Some 140 coal power plants are on the drawing boards, and the Energy Information Administration (EIA) projects that the U.S. will consume almost 1,800 million tons of coal in 2030, up from about 1,150 million tons this year. In addition, while EIA's estimates do not take coal-to-hydrogen production into consideration, it is not unreasonable to think that if the hydrogen economy ever comes to fruition, several recent studies suggest that coal could be a feedstock of choice, at least in the U.S. which has huge reserves of coal (~250 years' worth at current consumption rates), which are relatively cheap and easy to mine. An increase in future coal demand fuels legitimate concerns about the impacts on global climate and regional air pollution. While carbon capture and sequestration is often mentioned as a solution to these two problems, another impact, often overlooked, is the expectation that the current coal distribution infrastructure may not be able to reliably deliver the additional demand. Railroads deliver about two-thirds of U.S. coal at present, but certain coal-carrying rail corridors are already up against their capacity limits. Any future demand increases will probably necessitate significant capital investment by rail companies. This study seeks to identify existing capacity and potential constraints within the coal distribution infrastructure and to identify the costs of alleviating these constraints under four growth scenarios for coal demand. The scenarios differ based on whether or not pulverized coal (PC) or integrated gasification combined cycle (IGCC) plants are built, and the amount of coal that is used to produce hydrogen for fuel cell vehicles. In the scenarios, we assume that coal is the only feedstock used to meet all future hydrogen demand. We model coal transportation along the nation's vast rail network with a freight routing model that uses the Surface Transportation Board's confidential Carload Waybill Sample data as an input. For each coal demand growth scenario, we will identify which rail corridors will reach their capacity limits, and when, based on the increases in future coal traffic, and we will quantify the investment that will be needed to boost the capacity along those lines. To aid in our analysis, we will generate a number of rail traffic density maps for different years and scenarios. Some of the important questions that we hope to answer through this study include the following: (1) Will the nation's rail-coal distribution system be able to handle the future increases in coal demand that could result from traditional uses, as well as from coal-to-hydrogen production; and (2) What is the trade-off between building more efficient, though more expensive, IGCC power plants versus modern PC plants, if costly investments in the coal distribution infrastructure can be avoided? The work for this project is being carried out in collaboration with the U.S. Department of Transportation.

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