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The Closer We Get, the Worse It Looks
By Richard Heinberg, Posted by Kuzminski (about the submitter) Page 3 of 5 page(s)
Some depletionists see the world's enormous coal reserves as a partial supply-side answer to Peak Oil. Using a time-proven process, it is possible to gasify coal and then use the resulting gases to synthesize a high-quality diesel fuel. The South African company Sasol, which has updated the process, is currently under contract to provide several new coal-to-liquids (CTL) plants to China and has announced a plant in Montana.
CTL is not attractive to emissions analysts, however. While some carbon could be captured during the gasification stage (at a modest energy cost), burning the final liquid fuel would release as much carbon into the atmosphere as would burning conventional petroleum diesel.
A few depletion analysts tend to take a skeptical view of future coal supplies. According to most widely-quoted estimates, the world has at least two hundred years' worth of coal-at current rates of usage. However, factoring in dramatic increases in usage (to substitute for declining oil and gas supplies), while also taking account of the Hubbert peak phenomenon and the fact that coal resources are of varying quality and accessibility, leads to the surprising conclusion that a global peak in coal production could come in as few as 30 years (this conclusion can be extrapolated from a recent study for the DOE regarding the US coal supply).1
That raises the question: does it make sense to place great hope in largely untested and expensive carbon sequestration technologies if the new infrastructure needed will be obsolete in just a couple of decades? Imagine the world investing trillions of dollars and working mightily for the next twenty years to build hundreds of "clean" coal (and/or CTL) plants, with the world's electrical grids and transportation systems now becoming overwhelmingly dependent on these technologies, only to see global coal supplies rapidly dwindle. Would the world then have the capital to engage in another strenuous and costly energy transition? And what would be the next energy source?
Other low-grade fossil fuels, such as tar sands, oil shale, and heavy oil are also problematic from both the depletion and emissions perspectives. Some depletion analysts recommend full-speed development of these resources. However, the energetic extraction costs for these are usually quite high compared to the energy payoff from the resource extracted (also known as the energy returned on energy invested, or EROEI). Their already-low energy profit ratio would be compromised still further by efforts to capture and sequester carbon, since, as with coal, these low-grade fuels have a high carbon content as compared to natural gas or conventional oil.
Currently, natural gas is used in the processing of tar sands and heavy oil; from an emissions point of view, this is rather like turning gold into lead. Many depletionists point out that, while the total resource base for these substances is enormous, the rate of extraction for each is likely to remain limited by physical factors (such as the availability of natural gas and fresh water needed for processing), so that synthetic liquid fuels from such substances may not help much in dealing with the problem of oil depletion in any case.
Supply Side, Demand Side
By now a disturbing trend becomes clear: the two problems of Climate Change and Peak Oil together are worse than either by itself. Strategies that might help to keep lights burning and trucks moving while reducing emissions are questionable from a depletionist point of view, while most strategies to keep the economy energized as oil and gas disappear imply increasing greenhouse gas emissions. As we will see, the closer we look, the worse it gets.
As noted above, both groups need to design a survivable energy transition strategy in order to "sell" their message to policy makers. Carbon emissions come from burning depleting fossil fuels, the primary energy sources for modern societies. Thus both problems boil down to energy problems-and energy is essential to the maintenance of agriculture, transportation, communication, and just about everything else that makes up the modern global economy.
With regard to both problems there are only two kinds of solutions: substitution solutions (finding replacement energy sources) and conservation solutions (using energy more efficiently or just doing without). The former is politically preferable, as it does not require behavioral change or sacrifice, though it tends to require more planning and investment. The least palatable option, from a political standpoint, is also the quickest and cheapest-doing without (curtailing current usage). We have gotten used to using enormous amounts of energy, at rates unprecedented in history. If we had to use much less, could we maintain the levels of comfort and economic growth that we have become accustomed to? Could we even keep the lights on?
Several questions become critical: How much of a change in energy supply will be imposed by the peaking of production of oil and natural gas? How much will be required in order to minimize Climate Change? And how much of that supply shortfall can be made up for with substitution and how much with efficiency, before we have to resort to curtailment?
Climate analysts agree the world needs to reduce emissions considerably. In 1996 the European Environment Council said that the global average surface temperature increase should be held to a maximum of 2 degrees C above pre-industrial levels, and that to accomplish this the atmospheric concentration of carbon dioxide (CO2) will have to be stabilized at 550 parts per million (the current concentration is 380 ppm, though the addition of other greenhouse gases raises the figure to the equivalent of 440 to 450 ppm of CO2). But recent studies have tended to suggest that, in order to achieve the 2 degree cap, much lower CO2 levels will be needed. One study by researchers at the Potsdam Institute for Climate Impact in Germany concluded that-again, to keep the temperature from increasing more than 2 degrees C-the atmospheric concentration target should be 440 ppm of CO2 equivalents, implying that the atmospheric concentration of greenhouse gases will need to be stabilized at current levels.
But, to make the challenge even more difficult, it turns out that the biosphere's ability to absorb carbon is being reduced by human activity, and this must be factored into the equation; by 2030, this carbon-absorbing ability will have been reduced from the current 4 billion tons per year to 2.7 billion. Thus if an equilibrium level of atmospheric carbon is to be maintained through 2030, emissions will have to be reduced from the current annual level of 7 billion tons to 2.7 billion tons, a reduction of 60 percent. It is hard to imagine how, if that translated to a 60 percent reduction in energy consumption, it could mean anything but economic ruin for the world.
Depletion analysts look to about a 2 percent per year decline in oil extraction following the peak of global oil production, with the rate increasing somewhat as time goes on. Regional natural gas decline rates will be much steeper. The dates for global production peaks for both fuels are of course still a matter for speculation; however, it is reasonable to estimate that we might see more than a 25 percent or more decline in energy available to the world's growing population over the next quarter-century as a result of depletion.
Everyone would be happy if it were possible simply to substitute renewable sources of energy for oil, coal, and gas, and both depletion activists and climate activists support the expansion of most renewable energy technologies, including solar and wind. But there are realistic limits to the scale at which renewables can be deployed, and to the speed with which this can be accomplished.
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