Thursday, February 16, 2012

Fossil Fuels: They're Not Going Away Soon

Physicist, climate change believer, and peak oiler Tom Murphy takes a look at why fossil fuels refuse to die. Despite an ideological reluctance to admit the necessity of continuing to utilise fossil fuels throughout the 21st century, he was unable to get any other answer from the numbers he crunched.
Energy Bulletin Tom Murphy

In a strictly quantitative sense, the notion that we have an abundance of hydrocarbons yet may be accurate enough. I used the [above] plot in the post on peak oil, adapted from Brandt & Farrell. Dark shades indicate reliable resources, while light shades represent increasingly speculative holdings.

...We are about halfway through the conventional oil endowment—thereby near the production peak assuming the usual symmetric performance history. But perhaps we can recover a much greater fraction of the oil in the ground through advanced oil recovery technologies. Then we have tar sands and heavy oil from Canada and Venezuela. Or we can liquefy natural gas to cover the oil shortage. And... liquid fuel can be produced from coal. Finally, we have a potential option in oil shale. Resource estimates vary, but even taking the dark green segments in the picture above (reliable lower-bounds), we at least triple the remaining “liquid” hydrocarbon resource available.

...A number of techniques exist to improve the fraction of oil in a well that can be brought to the surface. Of course oil developers use every practical tool at hand to stimulate oil flow: pressurized water injection, horizontal drilling, hydraulic fracturing, and injection of gas like CO2 to dissolve into the oil and allow it to flow more easily. This last technique generally goes under the heading of Enhanced Oil Recovery (EOR), and can improve the extraction of oil by about 10% of the original in-ground amount. It runs a bit on the expensive side, but future energy will be expensive anyway. So this technique will help offset the decline, if employed at large scale, and has the advantage of delivering light crude oil that our infrastructure is geared to process.

...Heavy oil and tar sands will no doubt relieve some pressure on declining conventional oil, but they are capable of only partial relief. In other words, just because we believe the resource to be half-a-trillion barrels, rate-limited extraction will limit its ability to mitigate conventional oil decline. Did anyone notice that the U.S. does not own either of the large heavy deposits? Hey. Don’t discount Canada: last time we were in a war with them they burned down our White House!

...One barrel (160 ℓ) of fuel then requires about 250 kg of coal, leading to the association that each ton of coal yields 4 barrels of fuel. Replacing a 3% shortfall of about 200 million barrels per year in the U.S. requires an annual uptick in coal production of 50 Mt/yr, or a 5% increase, year over year, for a doubling time of 14 years. In a related measure, if the U.S. wanted to (or were forced to) cease oil imports, it would mean doubling coal production...

...Each liter of methane can create 0.64 g of octane, so that a liter of octane (at 700 grams) requires 1100 liters of natural gas. Replacing a 3% annual shortfall of 200 million barrels (at 160 ℓ/bbl) would then require 35 trillion liters of methane, or 1.2 tcf: a 6% annual increase in natural gas production—similar to the impact on coal. This isn’t too surprising since we currently get comparable amounts of net energy from gas and coal, and each being roughly half what we get from oil. So a 3% decline in energy from oil would need to be replaced by something like a 6% uptick in either replacement...

...No matter what mix we decide to pursue, if we wait until the decline starts before seriously ramping up all viable efforts in tandem, we will find economic hardship, job loss, energy volatility as demand flags and then resurges, etc. The unpredictable environment will not be conducive to large investments in risky alternatives. In short, we could get caught with our pants down. And if you’ve ever tried to run in this state, you know what happens next. _Tom Murphy Energy Bulletin
Murphy is one of the more rational peak oilers -- much like Robert Rapier -- but many of his assumptions are borrowed, and were not clearly thought through or well-supported by the persons who originated them. Should we blame Murphy for using faulty second-hand assumptions? No, because there is no easy way of avoiding doing so, given the sorry state of modern academia and media.

Murphy, for example, says that peak oil occurs when the resource is half depleted. That is one of many different definitions of peak oil, and not a very popular one among those who understand that humans do not know what the *&#! the resource will turn out to be in the end. But at least Murphy understands that the production curve is not likely to be a symmetrical logistic curve, for many reasons. Murphy says the reason is enhanced oil recovery, which will allow old conventional oil fields to keep producing far longer than currently anticipated. He is probably right about that.

But if he is right about that, then the numbers he uses for "depletion rate" in other sections of the discussion are wrong. BTW, the two terms "depletion rate" and "EROEI" do more to make monkeys out of peak oilers than anything else except perhaps the inability to stick to one clear definition of peak oil. ;-)

Of course, I haven't seen a peak oiler yet who understood the impact of the process heat from factory-built gas cooled modular nuclear reactors on the production of liquids from coal, gas, kerogens, bitumens, and biomass. But give them time.



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