approved. The administration's FY 1995 budget request includes coalbed methane recovery activities in the natural gas portion of the Fossil Energy program. As required by the Climate Change Action Plan (see above), EPA recently launched an outreach program to encourage coal companies to install methane recovery equipment at mines across the United States. The goal of this program is to reduce methane emissions from coal mines by at least 500,000 metric tons (25 billion cubic feet) by 2000 (Wamsted, 1994). DOE has developed a plan to expand RD&D for methane recovery from coal mining; DOE and industry will cofund projects on a 50 percent cost-sharing basis. This activity will be coordinated with the EPA outreach program.

Issues, Risks, and Opportunities

Technology for the recovery of coalbed methane from gas streams with high methane concentrations is commercially available and practiced by the gas and mining industries where conditions justify the investment. However, the collection and sale of methane are not widespread in the coal mining industry because of a number of technical and commercial issues. These include ambiguities in mineral rights concerning gas ownership, trade-offs between the selling price of methane and tax credits to encourage investments, the dependence of methane recovery on gas concentration and porosity of the coal or strata, the quantity and quality of gas to be vented, and constraints on the underground mining technique used (e.g., room and pillar versus longwall).

Technology for the use or control of coalbed methane emissions in very dilute gas streams (methane concentration less than 1.0 percent) is not currently available. Low-quality mine gases must be upgraded or enriched for sale to a distribution system. In view of the importance of methane as a greenhouse gas (see Chapter 3), opportunities exist to encourage the utilization of dilute methane streams emitted from coal mines by developing relevant technologies.

Possible research areas include new techniques for methane separation and the combustion of very dilute methane streams. Separation of methane from dilute ventilation air by conventional methods is expensive and energy intensive. Research aimed at finding new materials for selective adsorption or selective diffusion through membranes is of interest (see Chapter 9). Ventilation air streams are too dilute to burn in conventional combustion equipment without use of additional fuel, which would generate additional greenhouse gases. Catalytic combustion systems offer some promise, and advances made for other applications are of interest (see, for example, Haggin, 1994).

Findings

Coalbed methane recovery is a commercially available technology that is being practiced where concentrations are sufficiently high and where merited by the return on investment or benefits to mining.



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