METHANE EMISSIONS FROM COAL RELATED SOURCES IN BRITAIN - DEVELOPMENT OF A METHODOLOGY

Different methodologies for estimating annual atmospheric methane emissions have been reviewed. Evidence is presented which strongly suggests that the only straightforward and reliable methods for quantifying methane release resulting from coal mining activities are measurement based. All sources of coal related methane in Britain have been considered and annual methane emission estimates derived using both recent and historical data. The results indicate a general decrease in total atmospheric methane release over the last 25 years from about 1.4 Tg in 1966 to 0.75 Tg in 1990/91 corresponding to a downward trend in coal production. Reasonable estimates of coal derived atmospheric methane emission in Britain can be made by assuming a mean specific emission of 15.3 +/-2 m3 per tonne of deep mined coal. Contributions from other sources are unimportant as they only amount to about 1% of the total emission.