Coalbed Methane/Fuel Cell Operation for Direct Electric Power Generation

Haskew, Tim A. (The University of Alabama) | Haynes, Charles D. (The University of Alabama) | Boyer, C.M. (Dominion Energy Advisors) | Lasseter, E.L. (E.L. Lasseter and Associates, Inc.)

OnePetro 

Abstract

Methane released to the atmosphere during underground coal mining operations is a greenhouse gas and wastes a valuable energy 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 ill 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 $0.05/kWh is necessary for the direct generation of electric power from a coalbed methane/fuel cell system to be competitive.

Introduction

Methane released to the atmosphere during coal milling operations is believed to contribute to global warming and represents a waste of a valuable energy 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. Largely because of inadequate methane capture technology, less than 5 percent of methane released during coal mining is currently recovered for use. Improved design and technology to lower the costs of methane recovery could make it economically viable in many more mines, thus providing important environmental and safety benefits while enhancing the nation's natural gas supply.

Atmospheric concentrations of methane have doubled over the past two centuries and continue to increase. The Clinton Administration, recognizing the potential environmental risks of methane emissions, has developed the Climate Change Action Plan to control the growth of greenhouse gases in the atmosphere. The initial Plan looks for voluntary participation by the mining industry for increased methane capture. Should the voluntary actions be inadequate, future environmental initiatives will probably require the recovery of methane from coal mines, even though the technology to economically recover methane from coal mines has yet to be demonstrated for most mining situations.

This study investigated the feasibility of operating a phosphoric acid fuel cell power plant on variable-quality coalbed methane. This area of fuel cell power plant operation must be investigated because its application is far-reaching.

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