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Monday, August 27, 2007

Hooky Bump'in, and other parasitic relationships

As kids, we all probably participated in at least a few dangerous activities. Recently I started thinking about all the silly, parasitic modes of transportation I practiced (however briefly). By parasitic, I mean travel that requires a non-symbiotic relationship to an engine-powered hunk of steel -- think hitch-hiking where you attach yourself to a moving vehicle instead of hopping inside. A very obscure practice, known in certain wintry parts of the northern USA as "hooky bumping", ranks high in the danger (AKA "Jackass"-quality) category. To hooky bump, you needed iced or packed snow roads and a car or truck moving slow enough that you could grab on to the rear bumper. In the old days, car bumpers had some meat and you could actually hook your hands underneath and ride along like a crouched water-skiier. Nobody ever considered it that dangerous because you only came across the perfect hooky-bump conditions a few times a season. Stealth remained the key, as the car drivers' usually never figured out that they got hooky-bumped. The danger lied in the face-plant should you ever hit a piece of exposed asphalt.

Another parasitic travel technique, which actually took a lot of exertion, involved drafting city buses via a road bike. I used to do this commuting to school where buses stopped frequently enough that you could accelerate and quickly get within its slipstream (for a few blocks at least). The EROEI did not always pan out as imagined, especially if the bus driver notices you coming from behind and accelerates away. Professional road-bikers have this perfected, oftentimes forming the equivalent of a bus-human pelaton.

Somewhat related to bus-drafting, "door-hitching" required a bike and a friendly car-driving accomplice. Say you had a steep hill to climb and you happen to notice a friend driving alongside you in a car; the door-hitch request involves a twirling motion of the hand, indicating to the driver to roll down his window. If the driver obliges, you grab on to a window frame or ledge with one hand and continue to steer your bike with the other hand until you hit the top of the hill. Again likely illegal, but actually quite easy to perfect, as it has a lot in common with using tow-ropes or T-bars at downhill ski areas.

Putting a few of these techniques together and you can come up with other creative modes of parasitic transportation.

I often wonder how I made it past my teen years.

Saturday, August 18, 2007

Phosphate Depletion

A TOD poster and Energy Bulletin writer put together an intriguing analysis of phosphate depletion. As farmers use the phosphorus from rock phosphates as fertilizer to replenish the amount used up by crops, modern agricultural practices practically demands an ongoing and unlimited supply to keep production up. Although not quite as non-renewable as fossil fuel and helium sources, easily accessible phosphates practically assumes a non-replenishable role in planning for future resource utilization.

The authors, Dery and Anderson, applied Hubbert Linearizations to depletions on several scales and came up with what I would consider a valid empirical model for the current state of phosphate depletion.

As a nit, the "World Rock Phosphate Production" red curve they fit to above shows significantly asymmetry about the peak, particularly in the tails. Does this fit to the sigmoid function in the logistic derivation? If they fit to a sigmoid, the curve actually should show perfect symmetry about the peak. See below for a mirror image on the curve superimposed to show the asymmetry issue (note that by eyeballing, it might actually improve their visual fit).

Just recently, some real nitpickers have raked global warming climate scientists over the coals for an error correction that you can barely even detect in the graphs, see here and here. So it pays to make these corrections before the Freepers start to take potshots.

Otherwise, the post brings up some valid issues. Looking at a survey produced by the USGS [PDF], the authors seem not to even consider the potential critical importance of phosphate depletion:
U.S. phosphate rock annual production capacity is expected to fall during the next year when one mine in Florida and one mine in Idaho are anticipated to close because of depleted reserves. Production rates will not be affected though, owing to the reopening of a mine in Idaho and expansion at others in Florida. Complicated permitting procedures and public opposition to new mines have slowed the development of new mines in Florida. More than one-half of the current production capacity was expected to be exhausted by 2015, which would necessitate new mines or imports to maintain current production rates and leading world supplier status.
If you read between the "lah-di-dah" lines, the USGS authors seem to assume some new discoveries will take the place of ongoing depletion. As everyone seems to agree on, all plants and therefore all high-yield crops require phosphorus ... so we really have no substitute, other than to find more.

Of course, we can probably better back up a real argument for phosphate depletion by using better discovery and production models than the Hubbert Linearization heuristic favored by many oil depletion analysts and by Dery and Anderson themselves. In particular, I would suggest that the dispersive discovery model and the shock model would work and provide a set of valid physical parameters to use as a basis for analysis that the HL techniques do not provide. For one thing, it seems intuitive that the phosphorus deposits need easy access for profitable extraction. Fourteen years ago phosphate rock went for around $20 per ton (the post-processed fertilizer about $240 per ton), while a barrel of oil is about $70 for 0.136 tons (or $500/ton). That must have some impact on how far and deep we will go to recover phosphate rock, so a discovery model like the dispersive model we use for oil makes some sense.

Wednesday, August 15, 2007

the inevitable world-wide energy transition

'The oil boom is over'
These reforms come at a critical time. Saudi Arabia is barreling toward an economic and social crisis if it does not act fast. Almost 75 percent of Saudi citizens are under age 30 and youth unemployment is approaching 30 percent – a potential breeding ground for terrorists and regime dissidents. Current high oil prices are not enough to paper over the economic ravages of the past two decades. "The oil boom is over and will not return," (King) Abdullah told his subjects. "All of us must get used to a different lifestyle."

Thursday, August 09, 2007

Theory out the window

This theory on technological change sounds good on the surface, but I think he missed a key point.
The tendency of population to grow faster than the food supply, keeping most people at the edge of starvation, was described by Thomas Malthus in a 1798 book, “An Essay on the Principle of Population.” This Malthusian trap, Dr. Clark’s data show, governed the English economy from 1200 until the Industrial Revolution and has in his view probably constrained humankind throughout its existence. The only respite was during disasters like the Black Death, when population plummeted, and for several generations the survivors had more to eat.

Malthus’s book is well known because it gave Darwin the idea of natural selection. Reading of the struggle for existence that Malthus predicted, Darwin wrote in his autobiography, “It at once struck me that under these circumstances favourable variations would tend to be preserved, and unfavourable ones to be destroyed. ... Here then I had at last got a theory by which to work.”

Given that the English economy operated under Malthusian constraints, might it not have responded in some way to the forces of natural selection that Darwin had divined would flourish in such conditions? Dr. Clark started to wonder whether natural selection had indeed changed the nature of the population in some way and, if so, whether this might be the missing explanation for the Industrial Revolution.
To contrast what I emphasized in bold font, it just happened that the transition to dense versions of energy (coal and oil) and the use of this energy happened about this same time. So this rise in the middle class can arguably result from instead an improvement in productivity caused by the "strength of 20 mules" and not from a fantastically quick application of human natural selection.

Tuesday, August 07, 2007

Laherrere Interview

TOD Europe published an interesting interview with Laherrere:
TOD:E : Like other researchers (e.g. Hubbert, Marchetti) you use extensively the Logistic analysis as a predictive method, even though not everyone appreciate it as much. What makes you rely so much on the Logistic curve?

JL : Contrary to many researchers I use a several cycles model, I do not trust the Hubbert Linearization if the plot is not linear for decades. I use the derivative of the logistic function as model for each cycle because it is the simplest to plot using the peak value of the cycle, the peak date and the width of the cycle in years. Any other bell-shaped curve, as the Gauss (normal) curve, will work as well. I fit the last cycle to the last production value with the last trend (slope).

But I add in the text that this curve is to show simply what the geology can offer with the ultimate being the surface below the curve. But the supply has constraints from investment, politics, wars, insecurity and other constraints of the demand (high prices or recession). Any curve with the same surface below can fit depending the constraints. This is why I was also the first one to speak about a bumpy plateau instead of a peak.

What is important is to give the reader a production curve which has a surface below the curve equal to the ultimate. The curve can be modified to satisfy the constraints as long as the surface is conserved: any area below the model should be compensated by an equal area above the model. Most of forecasts are showing short periods before and after present, when mine are from the beginning to the end.

Hubbert in 1956 was modelling bell-shaped oil production by hand without any equation (he adopted the logistic curve much later) and he was saying that the production curve mimics discovery curve with a certain lag. He was right and often I do not model production, I just show production and shifted discovery to guess the future production by looking at the discovery curve which is ahead of the production time, as for example the natural gas of North America in the above graph in the NG chapter.
Laherrere has clearly used this "discovery shift" analysis in many of his figures. This natural gas curve shift looks rather startling:

As a caveat, note that Laherrere also performs a moving average filter on his discovery data, so that his shift has some stochastic elements. I wish he would remove the moving average so I could apply the shock model to it a bit more formally.

Compare to a recent post I made here on shifts in a discovery model to model production (recent as in before a vacation-induced dormancy).