PROJECTIONS FOR ULTIMATE COAL PRODUCTION FROM PRODUCTION HISTORIES

Accurate projections of ultimate production would be useful for climate policy, because the time scale for the climate response from burning coal is longer than the time for burning it. Early coal reserves studies were meant as estimates of ultimate production. For Great Britain, the largest producer of coal in the world in the 1800’s, a detailed supply study was done by a Royal Commission in 1871. However, now that 150 years have passed, and the cumulative production is 99% of the apparent ultimate, we can see that the reserves were too high. Britain has produced only 18% of the coal that the Commission thought was minable. It turns out that by fitting a logistic curve to the cumulative production history, an accurate projection for the ultimate (28Gt) becomes available by 1900, and it has not been more than 10% off since. There is a similar pattern for three other coal regions that have also apparently reached 99% exhaustion: Pennsylvania anthracite (5Gt), France and Belgium (7Gt), and Japan and South Korea (4Gt). In each case, reserves are available early in the production cycle, but they were too high, and curve fit to the production history gave better accuracy. However, in contrast to the accurate forecasts for ultimate production, the year of peak production has been quite variable, occurring at 43% exhaustion for the UK, 51% for PA anthracite, 65% for Japan and South Korea, and 78% for France and Belgium. I then tried to estimate ultimate world production on a regional basis with the same approach. In addition to the four mature regions, there are ten others. For eight of the ten, I am able to fit either a logistic or a cumulative normal to make a projection. The projections are Eastern US without PA anthracite 83Gt, Western US 46Gt, Canada 4Gt, Russia 83Gt, China 117Gt, Australia 52Gt, and Africa 23Gt, and the rest of Europe 127Gt. For South Asia and Latin America, the curve fits fail, because cumulative production has been growing by 5% per year in both. For these two, I use the reserves plus cumulative production as an estimate of the ultimates: South Asia 78Gt and Latin America 19Gt. The total of the 14 regions gives a projection for the world ultimate of 676Gt, 60% of the current World Energy Council reserves plus cumulative production, 1,130Gt. The projection has been stable within a 5% range since 1994.