Coalbed Methane/Fuel Cell Operation for Direct Electric Power Generation

Abstract Methane released to the atmosphere during underground coal mining operations is a greenhouse gas and wastes a valuable enery resource. Coal mining in the United States released an estimated 190 to 300 billion cubic feet (Bcf) of methane into the atmosphere in 1990. Based on the current trend of increasing coal production and the mining of deeper, methane-rich coal deposits, methane emissions from coal mines have been forecast to be 260 to 450 Bcf by 2010. Because of inadequate methane capture technology, less than 5 percent of methane released during coal mining is currently recovered for use. New initiatives for coalbed methane will increase its recovery, thus providing important environmental and safety benefits while enhancing the worldwide natural gas supply. This investigation determined the feasibility for installing a 200 kW phosphoric acid fuel cell at a large underground coal mine located in the Black Warrior Basin of Alabama. Assurance of supply, variation of coalbed methane quality, and economic feasibility were studied. The fuel cell can be operated directly from variable-quality coalbed methane produced from underground mining. Waste heat from the fuel cell can be used in the mine's coal dryer, allowing a portion of the coal normally consumed in the dryer to be sold. Excess electric power, if available, can be sold to the public utility grid. An energy cost of approximately SO.05/kWh is necessary for the direct generation of electric power from a coalbed methane/fuel cell system to be competitive.