A multi-Hubbert analysis of coal production by Tadeusz Patzek at The University of Texas at Austin and Gregory Croft at the University of California, Berkeley concludes that the global peak of coal production from existing coalfields will occur close to the year 2011. The HHV of global production is likely to peak in 2011 at 160 EJ/y, and the peak carbon emissions from coal burning will also peak in 2011 at 4.0 Gt C (15 Gt CO2) per year, according to the study.
After 2011, the production rates of coal and CO2 decline, reaching 1990 levels by the year 2037, and reaching 50% of the peak value in the year 2047. It is unlikely that future mines will reverse the trend predicted in this business-as-usual (BAU) scenario, according to the study, which was published in the journal Energy. (The accompanying online supporting materials provide the analysis of production by country.)
The most important conclusion of this paper is that the peak of global coal production from the existing coalfields is imminent, and coal production from these areas will fall by 50% in the next 40 years. The CO2 emissions from burning this coal will also decline by
50%. Thus, current focus on carbon capture and geological sequestration may be misplaced. Instead, the global community should be devoting its attention to conservation and increasing
efficiency of electrical power generation from coal.
…We repeat again that immediate upgrades of the existing electrical coal-fired power stations to new, ultra supercritical steam turbines that deliver electrical efficiencies of ca. 50% are urgently needed. The authors do not suggest that new coal-fired power plants be
constructed, unless they are to replace less-efficient existing coal-fired plants. The goal should be to increase efficiency rather than capacity.—Patzek and Croft
The paper provides a physical model of historical and future production of coal worldwide. The model demonstrates that despite enormous coal deposits globally, coal production rates will decline because the deposits show increasing inaccessibility and decreasing coal seam thickness, according to the research.
Other findings of the study include:
- The estimated CO2 emissions from global coal production will
decrease by 50% by the year 2050.
- Between the years 2011 and 2050, the average rate of decline of
CO2 emissions from the peak is 2% per year, and this decline
increases to 4% per year thereafter.
- It may make sense to have carbon capture and sequestration
(CCS) to alleviate the highest CO2 emissions between now and
the year 2020 or so.
Given the imminence of the global coal production peak, a better alternative would be to gradually replace the existing electrical power generation blocks with the new ultra supercritical
steam blocks (steam temperatures of 620-700 °C, and pressures of 220-250 bars), whose electrical efficiency is close to 50%, compared with the ~35% efficiency currently realized. This replacement might ultimately lower current CO2 emissions from coal-fired power stations by 15/35-40% for
the same amount of electricity.—Patzek and Croft
In the paper, Patzek and Croft developed a base-case scenario for global coal production based on the physical multi-cycle Hubbert analysis of historical production data. They treated areas with large resources but little production history, such as Alaska and the Russian Far East, as sensitivities on top of this base case, producing an additional 125 Gt of coal. They then compared their findings with 40 Intergovernmental Panel on Climate Change (IPCC) scenarios in the Special Report on Emissions Scenarios (SRES) Report. The Patzek and Croft resulting base-case is significantly below 36 of the 40 carbon emission scenarios from the IPCC.
Between the years 1990 and 2011 all but two of the IPCC scenarios are at or below the actual world coal production and emissions. In contrast, after 2011, most of the IPCC predictions increase unrealistically in a variety of exponential ways. Thirty-six out of 40 of these scenarios deviate significantly upwards from our base-case, up to a factor of 100…In particular, 2 IPCC
scenarios peak in the year 1990, 3 in 2020, 3 in 2030, 3 in 2040, 13 in 2050, while in the 16 remaining scenarios coal production simply grows exponentially until the year 2100.
Because IPCC did not rank its forty scenarios on purpose, the 16 nonphysical outliers, and 4 other scenarios, 8 were given de facto a weight equal to the more
realistic lowest scenarios. The policy makers tend to focus on the most extreme outcomes, and the outliers have gained prominence as inputs to the subsequent climate models. The real problem 40 years from 2009 will be an insufficient supply of fossil energy, not its overabundance, as the IPCC economists would have it.—Patzek and Croft
Because their study is a multi-cyclic Hubbert analysis, the authors noted, the possibility of future cycles that are not reflected in the historical data must be considered. The base-case in the study includes all coal-producing regions with any significant production history. New mines in existing coalfields should be part of existing Hubbert cycles and thus are part of the base-case.
However, new cycles could occur if a technological breakthrough allowed mining of coal from very thin
seams or at much greater depths, or if non-producing coal districts
become important producers.
The current paradigms of a highly-integrated global economy
and seamless resource substitution will fail in a severely energy constrained
world. A new territory is being charted by all, thus
close attention must be paid to what the physical world reveals
about energy conservation and production.
…In view of the imminent difficulties
with the coal supply, a lasting increase of natural gas
production in the United States is of utmost importance.—Patzek and Croft
Tadeusz W. Patzek and Gregory D. Croft (2010) A global coal production forecast with multi-Hubbert cycle analysis. Energy
Volume 35, Issue 8, Pages 3109-3122 doi: 10.1016/j.energy.2010.02.009