PROJECTIONS FOR ULTIMATE COAL PRODUCTION FROM PRODUCTION HISTORIES THROUGH 2012

Accurate projections for coal production in the long run would be valuable for alternative-energy policy and for climate policy. Despite many government programs to encourage alternative energy sources, the fraction of the world’s primary energy that is provided by fossil fuels has not budged from 85% since 1990. This is because rising wind, solar and biofuels have been offset by the decline in the share of nuclear energy. In addition, it would be difficult to argue that climate policy has significantly limited world coal production so far. During the time the Kyoto Agreement was in effect from 1997 to 2012, world coal production rose 66%. This suggests that we consider ways to estimate the scale and time frame for fossil-fuel production in the long run that do not include assumptions about alternative-energy policy and climate policy. The early approach to this problem was to do a careful reserves survey, making allowances for losses in production. For example, a British Royal Commission made a detailed study of the country’s coal supplies in 1871. However, it is now clear that their estimates were six times too high. Something similar happened in the world’s other mature coal regions: France and Belgium, Japan and South Korea, the Pennsylvania anthracite fields, and the Ruhr bituminous field. The early reserves were all more than a factor of two higher than the production that followed. In spite of this history of reserves over-estimation, in the modern economic model RCP 8.5 (where RCP stands for representative concentration pathway) that is most commonly used for climate calculations, it is assumed that a multiple of the reserves will be available for production. Here it is argued that better estimates can be made by s-curve fits to the regional production histories, with reserves as a fallback where the curve fits do not converge yet. This approach gives a range for the ultimate production of 667-785GtGt, including the cumulative production through 2012 of 334Gt. This compares with World Energy Council reserves plus cumulative production of 1,165Gt. The s-curve fits also give a time frame for the production. Time estimates should be regarded as tentative because historical events like the collapse of the Soviet Union have changed the trends in the past. If the current trends continue, 90% of the coal would be produced by 2067.