A new model for calculating global goal reserves created by Dave Rutledge, chair of Caltech’s engineering and applied science division, shows that previous estimates may overstate, by hundreds of billions of tons, the amount of economically recoverable coal left in the ground.
Rutledge estimates that the total amount humans will extract, including all past mining, is only 662 billion tons. Far less that the previous best guess from the World Energy Council of 850 billion tons still available for mining
Basing his new model on historical examples of fossil fuel exhaustion, Rutledge notes the consistency with which governments fail to accurately estimate their own fossil fuel reserves. “The record of geological estimates made by governments for their fossil fuel estimates is really horrible. And the estimates tend to be quite high. They over-predict future coal production.”
As examples Rutledge noted the precipitous decline in British coal reserves after its 1913 peak, and the U.S. peak oil production of 1970, “controversially predicted” by M. King Hubbert in 1956 (and who was one of the first to warn of the unsustainability of fossil fuels starting in the ’40′s).
Methods of estimation need updating
The estimates presented by Rutledge’s calculations have yet to be validated, but the National Research Council’s Committee on Coal Research, Technology, and Resource Assessments to Inform Energy Policy (a mouthful) concur with the general criticisms he makes.
While they still think there’s more coal in the ground than Rutledge’s model suggests, they warn that estimates of U.S. coal reserves aren’t as high as previously thought and that methods of estimating recoverable reserves should be updated. A 2007 report from the committee states: “Present estimates of coal reserves are based upon methods that have not been reviewed or revised since their inception in 1974, and much of the input data were compiled in the early 1970′s. Recent programs to assess reserves in limited areas using updated methods indicate that only a small fraction of previously estimated reserves are actually mineable reserves.”
Good news for the climate – sort of
Coal is the wildcard in climate change. Specifically, how much we humans end up burning to generate electricity, the biggest driver of anthropogenic climate change. And if the estimates for coal reserves presented by Rutledge are accurate, there will be far less of it to burn and, thus, less potential CO2 emissions.
Stanford ecologist Ken Caldeira said of the new study, “Every estimate of the ultimate coal resource has been larger. But if there’s much less coal than we think, that’s good news for climate.”
While it may be good news, it’s wildly optimistic (and irresponsible) to assume that we could or should continue to develop and burn coal unabated. Even if Rutledge’s numbers are correct, and humanity decides to burn all the coal available (along with other fossil fuels), atmospheric concentration of CO2 will likely rise to at least (or “only”) 460 parts per million. While a far cry from some of the gloomier scenarios of possible concentrations of 500, 700, even 1000 PPM set forth by organizations like the IPCC (who believe global coal reserves could be 5 times as much as Rutledge’s estimate), it is still too much. Many climate scientists now say that global CO2 levels should stabilize at 350 PPM to avoid the worst consequences of climate change. Current levels are now around 380 PPM.
Phasing it out vs. using it up
Even if there is far less coal than previously thought, it’s foolhardy to think we could just “use it up” and everything will be alright. Pushker Kharecha, a scientist at NASA’s Goddard Institute for Space Studies sums it up well: “Coal emissions really need to be phased out proactively – we can’t just wait for them to run out – by the year 2030. There is more than enough coal to keep CO2 well above 350 ppm well beyond this century.”
EIA report shows decline in coal production
The annual long-term forecast recently issued from the Energy Information Agency projects 46 gigawatts of coal-generated power by 2030, down from 104 gigawatts from last year’s forecast. This year utility companies have cancelled construction on 13 coal-fired plants.
Certainly coal will remain a dominant player for power generation for years to come, but with rising concern about global warming and anticipation of federal emissions targets spurred by president-elect Obama’s call for an 80% reduction in emissions over 1990 levels by 2050, it won’t much matter if Rutledge’s numbers are right or not. Any way you look at it, burning coal is an unsustainable energy policy.
A recent study conducted by the consulting firm Delloitte show only 17% of 50 senior oil and gas executives believe fossil fuels will be the most sustainable source of fuel in 25 years. 23% think fossil fuel will be the cheapest. The report shows that most industry leaders believe that within 25 years renewable energy will provide the most sustainable and cheapest source of fuel. Sure, we still may have to endure silly animations of little chunks of coal dressed in holiday attire singing the praises of “clean” coal, but we all know better. Whether there is 850 billions tons left, or less than 662, the transition away from coal has already begun. Time will tell if it is fast enough.