In my last post, I recounted some of the indications that have surfaced over the last decade that US coal reserves might not be as large as we think. The work done by the USGS assessing our reserves, and more recently comments from the coal industry themselves cast doubt on the common refrain that the US is “the Saudi Arabia of coal” and the idea that we have a couple of centuries worth of the fuel just laying around, waiting to be burned. As it turns out, the US isn’t alone in having potentially unreliable reserve numbers. Over the decades, many other major coal producing nations have also dramatically revised their reserve estimates.
Internationally the main reserve compilations are done by the UN’s World Energy Council (WEC) and to some degree also the German equivalent of the USGS, known as the BGR. Virtually all global (publicly viewable) statistics on fossil fuel reserves are traceable back to one of those two agencies. For instance, the coal reserve numbers in the International Energy Agency’s (IEA’s) 2011 World Energy Outlook came from the BGR; the numbers in BP’s most recent Statistical Review of Energy came from the WEC.
Of course, both the WEC and the BGR are largely dependent on numbers reported by national agencies (like the USGS, the EIA and the SEC in the case of the US), who compile data directly from state and regional geologic survey and mining agencies, fossil fuel consumers, producers, and the markets that they make up.
Looking back through the years at internationally reported coal reserve numbers, it’s surprisingly common to see big discontinuous revisions. Below are a few examples from the WEC Resource Surveys going back to 1950, including some of the world’s largest supposed coal reserve holders. In all cases, the magnitude of the large reserve revisions is much greater than annual coal production can explain.