The pit-prop that supports much of the current energy debate about what we will do once Hubbert's Peak has passed, is the belief that the world has plenty of coal. Well, David Strachan*, who brought us "The Last Oil Shock" has some more bad news…
Geoscientist 18.3 March 2008
Depending on your standpoint, coal represents either a massive threat to the climate, or a potentially vital substitute fuel as global oil production heads for terminal decline. Either way, it is commonly agreed that coal will last for well over a century. But a number of recent reports suggest that coal reserves may be hugely over-inflated, with profound implications for both oil depletion and global warming debates.
The latest ‘official’ statistics (World Energy Council Survey of Energy Resources) give global coal reserves as 847 billion tonnes at the end of 2006. Since coal production that year amounted to just under six billion tonnes, these reserves appear ample to sustain output well beyond even the most distant planning horizon. In the context of recent trends, however, these numbers are not so reassuring. Reserves have fallen by over 170 billion tonnes over the last 20 years, and in terms of the reserves-to-production (R/P) ratio (the number of years the reserves would theoretically last at current consumption) the deterioration has been even more dramatic.
A report from the EU Institute of Energy published in February 2007 calculated that the R/P ratio dropped by almost a third - from 277 years in 2000 to just 155 in 2005. If this rate of decline were to continue, the report warned, “the world could run out of economically recoverable reserves of coal (at current economic and operating conditions) much earlier than widely anticipated.” In 2006 the R/P dropped again to 144. The question of why coal reserves are falling so fast, and whether the trend will continue, is only now beginning to be asked.
One reason is clear: consumption is soaring, particularly in the developing world. In 2006 China alone added 102 gigawatts of coal-fired generating capacity - enough to produce three times more electricity than California consumed that year. China is already the world’s largest coal producer; yet such is its appetite that in 2007 it still became a net importer.
Another less often remarked reason is that in recent years many countries’ official coal reserves have been revised downwards, sometimes massively, and often by far more than those countries had mined since the previous assessment. For instance Britain, Germany and Botswana have all cut their reserves by over 90%, and Poland by 50%. Global reserves of high quality ‘hard coal’ have been reduced by 15% - again more than could be explained by mining alone. Meanwhile other countries (e.g., China, Vietnam) have left their official reserves numbers suspiciously unchanged for decades while producing billions of tonnes of coal in the interim.
As a result, according to a report from Energy Watch, a group of independent scientists led by the German renewable energy consultancy Ludwig Bölkow Systemtechnik (LBST), coal reserves data are likely to be biased on the high side. “As scientists we were surprised to find that so-called proven reserves were anything but proven”, says lead author Dr Werner Zittel; “It’s a clear sign that something is seriously wrong”.
Since the preponderance of reserve revisions has been downwards, and since it is widely accepted that major new discoveries of coal are unlikely, Energy Watch concluded that the current reserves figures are likely to represent the upper limit of available coal, meaning that production will stall far sooner than expected. On the basis of a country-by-country analysis, the group forecasts that global coal output could rise by about 30% over the next decade but will peak as early as 2025 and then fall into terminal decline. From that point on they say there will be progressively much less coal available than is widely assumed by policymakers, who are generally guided by the much higher forecasts of the International Energy Agency’s World Energy Outlook (WEO), which are in turn based on the ‘official’ reserves figures.
According to Jörg Schindler of Energy Watch and LBST, policymakers are in for a shock. “The perception that coal is the fossil resource of last resort, that you can come back to when you run into problems with all the others, is probably an illusion”.