Wednesday, November 28, 2007
As has been pointed-out, the hippoville is not a pollution-free vehicle, since a 1,000 pound horse produces about 50 pounds of dung every day along with six to ten gallons of urine, and which if soaked-up by bedding (straw) would provide another 50 pounds daily. Extrapolating, over a year, such a horse will produce about ten tonnes of dung and an equivalent amount of urine/straw. Now when I was a child, it was a common sight to see people going behind a horse, picking-up its dung to put on their gardens. Rhubarb was particularly favoured for this treatment, as became the subject of a number of British lavatorial jokes; such is our sense of humour. So, the horse exhaust-products could be put to good use in agriculture.
It is worth recalling that before the motor car became popular, there was speculation that the projected future number of horses would leave city-folk waste-deep in dung and it was noted the considerable effort of New York City in disposing of some 12,000 horse carcasses per year. I presume they were rendered-down to make glue and for other purposes. I walked past an expensive restaurant in Thun in Switzerland, some time ago, and noted with surprise that "pferderfleisch"was on the menu, "horse meat", and so this might prove another advantage to the horse, at least in some countries, though I doubt it over here, in this nation of animal-lovers.
Quite seriously, I fully expect to witness a come-back for the horse, amid the society of local farms and small communities that I envisage we will return too, from whence we came before the age of cheap-oil. As Thomas Hardy described in his novels, e.g. The Mayor of Casterbridge (his alias for Dorchester, in the south-west of England), such an agrarian lifestyle was extremely hard, especially if you were poor. He describes the journeyman farm labourers who walked 20 miles a day in search of work, and worked for a few pennies a day until that work was done, and then on to whatever next they could find. There was no welfare state then, and if a labourer was ill, or injured in this terribly dangerous profession, he simply got no money.
I do not envisage this extreme, but an emphasis on home-production - local farms and breeding horses and other animals is more realistic than the "hydrogen economy" for instance, or other technical fixes that will not be introduced in time, or if at all, to save us from the imminent energy-crunch, particularly in terms of transportation. If this nation and others must become as near self-sufficient as possible to survive, the horse will become an essential ingredient of the "energy mix" we often hear about.
(1) "The horse: Is this the secret weapon to beat global warming?" By Geoffrey Lean, Environment Editor for The Independent. http://environment.independent.co.uk/climate_change/
Monday, November 26, 2007
API gravity = 141.5/(specific gravity - 131.5).
By rearranging this, the specific gravity (SG) may be deduced as:
SG = 141.5/(API gravity + 131.5).
Hence, the Tupi oil has an SG of: 141.5/(28 +131.5) = 0.887 kg/m^3
However, the case of Tupi is complex, and recovering the oil is going to be a considerable task. The oil lies under a layer of salt, which lies under a layer of rock, which lies under great depths of sea. Probably the rock (pre-salt layer) lies under 2 - 3 kilometres of water, and is itself maybe 2 kilometres thick. The salt layer is gauged-in at around another 2 km in thickness, and having got through all that, there lies the reservoir of oil, and probably gas too, since oil cooked at such depths (and according temperatures) in all likelihood has produced gas.The company working on the TUPI project, Petrobras, is currently exploring for oil and gas in waterline-to-reservoir depths of 5 km, and is the world leader in offshore hydrocarbon exploration.
The salt-layer itself poses some particular challenges. Drilling through salt has been done before, but at Tupi the salt-layer is of an unprecedented thickness for drilling and the depths involved are greater than have been tackled before. To get some idea of the pressure, we can note that the pressure of water increases by about one atmosphere for every 10 metres depth. For solid crustal material, it is nearer three atmospheres for each 10 metres of descent (and an average of 4.5 atm./10 metres at much greater depths). Hence, if the sea layer is 3 km, that imposes 300 atm., below which is 2 km of rock, i.e. 3 x 200 = 600 atm, and then the salt itself, which yields another 600 atm. say, a grand total of 1500 atm. pressure (around 1.5 x 10^8 Pascals or 0.15 Gigapascals, GPa).
The salt is also heated by geothermal energy (from the interior of the Earth), and under these combined conditions of pressure and heat it behaves less like a solid and more like a jelly, with properties of flow, and so a hole may be drilled through it but it then closes. At the Coordination of Post-Doctoral Engineering Programmes (COOPE) hosted at the Fedreal University of Rio de Janiro, there are three high-pressure chambers that permit the simulation of the conditions at depths of 6000 metres, and where drilling equipment is tested.
Another problem is that when oil is pumped-up from the reservoir, it is hot (100 degrees C) and fluid, but at the sea floor temperatures are only around 2 degrees C. where the oil becomes "thick" and this can block the flow of oil to the surface. It is possible to get around this by heating the pipes, but this all adds to the costs of recovering the oil. The weight of the very long, 7 km, pipes can also impose mechanical stress on the steel they are made of and one suggestion is to use titanium instead, but this is a far more expensive material, adding further to the final bill.
On a final note, even at the predicted production from Tupi of 400 kb/d by 2015, this amounts to just 0.4/80 x 100 = 0.5% of the 80 million barrels a day of oil that the world currently uses, and who knows what it will cost per barrel to produce. Either way, as it becomes necessary to drill in increasingly difficult places to get it, oil will become a very expensive commodity, and perhaps other forms of "oil", e.g. as produced from Coal to Liquids (CTL) plants, now considered expensive, or Biomass to Liquids (BTL), thought to be operational technology by 2020, may become economically viable. Either way, the age of cheap oil is well and truly over.
(1) "Tupi, the new kid in town", By Luis de Sousa: http://europe.theoildrum.com/node/3269
[In general, oils with an API gravity of 40 to 45 have the highest market price and those with values outside this range sell for less. Above an API gravity of 45, the molecular chains become shorter and are less valuable to a refinery. Crude oil classified as light, medium or heavy, on the following basis:
Light crude oil has an API gravity of above 31.1 °.
Medium oil has an API gravity in the range 22.3 ° and 31.1 °.
Heavy oil has an API gravity less than 22.3.
In contrast, the US Geological Society uses slightly different definitions, but put simply, bitumen sinks in fresh water, while oil floats.
Oil which will not flow at normal temperatures is defined as bitumen for which the API gravity is normally less than 10 °. Bitumen derived from the oil sands deposits in the area of Alberta in Canada, has an API gravity of around 8 °. It is 'upgraded' to an API gravity of 31 ° to 33 ° by dilution and the upgraded oil is known as synthetic crude].
Thursday, November 22, 2007
"I will not cease from mental fight,
Nor shall my sword sleep in my hand
Till we have built Jerusalem
In England's green and pleasant land."
It is sung by strong men at rugby football matches, with tears in their eyes, but it could be taken as an environmental anthem. However, while Britain is still a green land, that could all change as future events take their course. Fields of biofuel crops could take the place of pastures of grazing animals, while enormous acres of same-cultivated crops cover space between identical urban landscapes, villages as we know them, no longer in existence. A report from Natural England entitled "Tracking Change in the Character of the Urban Landscape," has concluded at 40% of the nation's landscapes are deteriorating from their traditional vistas.
There is public antipathy toward farmers, as they are often perceived: taking hefty EU subsidies while creating mountains of potatoes and butter that nourish no one; polluting rivers and streams; cutting-away the hedgerows to make enormous fields to grow more crops for more profit, while killing wild animals and birds. The list could go on. It is truth, however, that a mere 60% of our food is produced within the nation's borders. It is clear too that food prices will soar, but this is no fault of the farmers - inevitably oil prices will make the production of food and its transportation more expensive and so the produce itself, whether grown at home or imported from elsewhere. Food production has in fact fallen by around 1% per year for the past 15 years.
Farmers have been "hit" by BSE, swine-fever, foot-and-mouth disease, to name a few tragedies, while bird-flu constantly threatens further calamity. The suicide rate among farmers is the highest of any occupation, and it is also a truth that few other industries are forced to sell their production at less than cost-price. Public transport in the countryside is generally lamentable and so even the rural "poor" need to be multi-car families, to access basic services such as schools, the doctor, the bank and buying food. Those in this position will suffer greatly as prices, especially of fuel, rise.
To accord with the desired nearly 6% of Europe's fuel demand to be provided in the form of biofuels by 2010, some 3 million tonnes of wheat from a total of 15 million tonnes would be required in the UK, thus removing it from the food market, and eliminating any such surplus for export. The economic success of China means that its population will most likely move from a diet based on rice to one based on grain, and that will put pressure on world markets, possibly to a doubling in grain consumption within 40 years. To produce more food means either planting crops that give greater yields per care or cultivating more land.
The EU has reduced the amount of "set-aside" land from 8% in 2006-2007 to zero in 2007-2008, but since this land is much less productive it will not yield another 8% of crops - it tends to be stony, the headlands, fens and that in forests. There will be major changes make to the countryside, including moving animals to uncropable hill-land, in an effort to cram as much crop production wherever they can be grown. GM (genetically modified" crops are also thought might be necessary as they give higher yields, although the debate over GM has not yet been resolved.
Supporters of nuclear power claim that its preponderance will reduce the amount of land needed to produce biofuels, by which I presume they mean that nuclear can be used to produce hydrogen, and that instead can be a source of transportation energy. I have my doubts about this, on any significant scale, but nuclear power can certainly help us to keep the lights on. All in all I read the signs here as a call to maximise national self-sufficiency certainly in food, while the problem of providing transportation fuel remains, as oil becomes increasingly expensive and in short supply.
"Goodbye beautiful Britain," Sunday Times Online, August 26th, 2007. http://www.timesonline.co.uk/article232876.ece/print
Monday, November 19, 2007
Now, F. William Engdahl has countermanded his stance that oil is about to run-out, and believes that the biogenic theory of oil production, favoured the the West, is untenable. I think there is a good point being made here, that for the latter hypothesis to be true, to form the massive Ghawar field in Saudi Arabia, dead dinosaurs etc. would have needed to be trapped to a total volume of 19 miles cubed, at depths maybe 4,000 - 6,000 feet below the Earth's surface, and elsewhere at offshore locations such as the North Sea and the Gulf of Mexico, in rock formations. There are various theories about the events that might have occurred at the Earth's surface (we don't really know what has happened or still does at its greater depths), but it is possible that the pervasion of life and its separation following the break-up of Pangea, tectonic motion or pole shifting (that is the literal slipping of the Earth's crust over the semi-fluid asthenosphere; a terrifying scenario to put it mildly!) might have left its remains thus... but nobody really knows.
However, there may well be many different sources of petroleum. Hydrocarbons may represent an "energy minimum" into which more complex molecules can be "cooked", and there may indeed be unimaginable trillions of tonnes of "oil" lying under our feet. Some may come from animal/plant detritus, and other, presumably deeper volumes from geochemical processes. But this changes nothing about the crisis (in transportation fuel especially) that faces the world. If such reserves do exist, how accessible are they, and in what amount can they be reasonably extracted?
My understanding is that "deep-drilling" is necessary to access these sources, irrespective of their origin, and so there are limits to how fast we can pull petroleum from the earth to match the 30 billion annual barrels that we currently demand from her. It is a simple question of supply and demand, and we are demanding an inexorable amount of oil. Russia is apparently drilling deep wells around the Caspian coast, with alleged success, and yet I can find no confirmation of this. Either Russia will become the world's greatest producer of petroleum and hence the major world superpower, transcending the United States, or it will suffer the fate of all industrialised societies, which will necessarily relocalise into smaller communities in an effort to survive. In any case, the preponderance of cheap oil is over, and ergo the modern world and our customarily associated lifestyles upon it. There will always be oil, in all likelihood, but it's going to cost.
(1) "The Deep Hot Biosphere", by Thomas Gold, ISBN: 0-387-95253-5, Copernicus Books, 2001. (Available from Amazon.com and Amazon.co.uk).
(2) "Jagged Environment", by Chris James, ISBN: 0-954-00940-1, JEpublications, 2001. (Available from Amazon.co.uk but not Amazon.com...). Or from http://www.jaggedenvironment.com
(3) "Confessions of an "ex"- Peak Oil Believer," By F. William Engdahl: http://www.engdahl.oilgeopolitics.net/print/Peak%20Oil.htm
Thursday, November 15, 2007
China's demand for oil, copper, zinc, nickel and all other basic resources is forcing their prices increasingly upward, and the International Energy Agency (IEA) has predicted that the thirst for oil by China and India will quadruple by 2030. Whether this will really happen, given the lack of available crude oil way before then, it seems there will be a "crunch" in supply by 2015. Significantly, 2015 is the upper limit predicted by the Norwegian Statoil for the emergence of the "peak" in oil production, which they forecast could hit as soon as 2010. More likely the peak is already with us, as some analysts think, and the output of oil is being maintained artificially by enhanced recovery methods; hence, beyond the peak, oil supplies will drain rapidly, and it is not obvious to me how any increase in oil production is then possible, let alone a quadrupling in consumption by the Chinese or Indian industrial leviathans.
Meanwhile, China has asked for a 30% increase in its imports of crude oil from Saudi Arabia, and plans also to increase its imports of oil from Iran, having built two new oil refineries to increase the nation's fuel capacity. It is expected that imports of Saudi crude will increase from 460,000 barrels per day (bpd) to 600,000 barrels next year. The two new refineries can handle 240,000 bpd (Fujian on the south east coast) and 200,000 bpd in Shandong province, both of which are scheduled for completion next year. Apparently, China is unperturbed by the US sabre-rattling over the Iranian uranium enrichment programme, and wants to increase oil imports from the country above the 17% enhancement rise during the first nine months of 2007.
When such information about the burgeoning Chinese Economy is quoted, it is usually done so in the spirit of culpability toward its nation. However, it is the West that drives growth, in buying manufactured goods from China, much cheaper than we could make them ourselves. Western Culture is the counter-trade of this imported booty, in terms of quite understandable aspirations toward a "western lifestyle", which in reality even the West can no longer afford to maintain, or not for much longer, against the backdrop of rising oil prices. Therefore, outlets of McDonalds, Starbucks and Kentucky Fried Chicken (KFC) have appeared in the Chinese novo riche east. The traditional rice-diet is being superceded by a meat-rich diet, and imports of pork, beef and milk, which used to be in short supply in China are soaring.
In an effort to assuage memories of an austere socialist past, and mass starvation at times, China is now a net importer of food. As I wrote in "Can we Feed the World?", even if all of us (in the East and the West) adopted a pre-Green Revolution diet, which was largely vegetarian since meat production is more intensive in terms of the amount of land required per person to survive upon, only about 3 billion might be maintained as a total global population, or less than half the current number of 6.5 billion, in the absence of synthetic pesticides and artificially manufactured fertilizers.
To call this scale of events economic "growth" is illusory, since it reflects the plundering of the earth's resources under the false premise that we can continue to consume more and more, essentially forever and without limit, in terms of oil, food and energy. The reality is an artificially enhanced population with relentlessly voracious tastes, and a finally greater die-off in its numbers if world resources, and that includes its population too, are not managed to the aim of a sustainable balance between what might be supplied and what might reasonably be demanded from the capacity of the earth. The weight of demand has swung way down, and our chances of pulling-out of the nose-dive we are into, diminish increasingly in this protracted state of addicted denial. We need to trammel-in "growth" according to a definite worldwide plan. The governments of the world must decide on how to sustain its populations, and the available natural wealth must be apportioned to do so.
(1) "How China is Eating the World," By Sean O'Grady, The Independent, November 9th, 2007. http://news.independent.co.uk/business/analysis_and_features/article3143288.ece
(2) "China seeks 30% increase in Saudi oil imports," Reuters, Friday November 9 2007. http://www.guardian.co.uk/feedarticle/print?id=7063791
Tuesday, November 13, 2007
However, I was sent a an early press-release of a paper which reports on the greatly enhanced production of hydrogen, in yield and rate, that might be achieved by immobilising hydrogen-producing bacteria onto the surface of an electrode, passing a current and thereby stimulating the proton and electron generating activity of such "exoelectrogenic" bacteria using a small applied voltage. The cell is described in , and is impressive, in comparison with simply having hydrogen producing bacteria swirling around in a stirred fermentation vessel. Naturally, there are additional resource demands incurred by this more sophisticated technology, which employs a cathode made of carbon cloth onto which a platinum catalyst is supported. The anode chamber was filled with graphite granules and a graphite rod was inserted into the granules.
Bacteria from a soil or waste-water source were inoculated and enriched on a specific substrate using a phosphate buffer and nutrient medium. High yields of hydrogen were obtained from glucose and also from its commonly encountered fermentation products, e.g. acetic acid, butyric acid, lactic acid, propionic acid and valeric acid, meaning that by a change in applied voltage it might be possible to produce hydrogen from these too, and thus rendering the process of fermentation overall more efficient in respect to hydrogen production.
By looking at some rough numbers, it is possible to gauge the likelihood of the technology being adopted on the large scale, in order to match the amount of oil we currently get through in terms of fuel.
The reactor volume is given as 14 mls (anode chamber) and 28 mls (cathode chamber), making a total of 42 mls, from which 1.1 m^3 of H2 is obtained per day. The cathode has an area of 1 cm^2 and is made of carbon cloth on which 0.5 mg of Pt has been deposited.
To match 60 million tonnes of oil, we need about 6 x 10^9 kg of H2 (6 million tonnes). 1 kg of H2 is 500 moles, and occupies a volume of:
500 moles x 24.5 litres/mole/1000l/m^3 = 12.25 m^3.
Hence, 6 x 10^9 kg of H2 has a volume = 12.25 m^3/kg x 6 x 10^9 kg = 7.35 x 10^10 m^3
The reactor produces 1.1 m^3 of H2 per day x 365 days/year = 401.5 m^3/year.
Therefore we need: 7.35 x 10^10 m^3/year/401.5 m^3 H2/m^3 (reactor volume)/year =
1.83 x 10^8 m^3 reactor volume.
[This is a huge improvement over the 1.5 x 10^11 m^3 for a "free" fermentation process, and implies a factor of 800 less in terms of water required. However, in some of the fermentations, water is a reactant but even so, we still need much less than 1% of the comparable quantity of water to run it].
How much platinum is required? 0.5 mg/cm^2/42 mls of reactor cell volume in total.
1.83 x 10^8 m^3/42 x 10^-6 m^3 x 0.5 mg = 2.18 x 10^3 tonnes of Pt = 2180 tonnes. This is equal to the world output of new platinum for 14 years, and that is just to fit the UK's needs, let alone the rest of the world! Thus we have hit the first resource bottleneck.
We would also need 50g Pt/fuel cell x 33 million cars on UK roads = 1650 tonnes of new Pt for fuel cells in which to "burn" the hydrogen, making 3830 tonnes of Pt required in total, or 25 years worth of the world output of the metal.
How much land would be needed to grow the sugar crop? Let's assume that the technology can be adapted to extract 100% of the hydrogen in a sugar C6H12O6 (including the acids etc. that it produces in a first fermentation) which is pretty optimistic:
C6H12O6 ---> 6CO2 + 6H2 + 6 "O" (in an unspecified chemical form).
MW = 180 12
So, we need 180/12 x 6 x 10^9 kg H2 = 9 x 10^10 kg = 9 x 10^7 tonnes of glucose.
If we assume a yield of 19 tonnes of "sugar" per hectare, and an efficiency of 80% to extract the hydrogen, we need:
100/80% x 9 x 10^7/19 = 59.21 x 10^6 ha of arable land = 59,210 km^2 which is 91% of the total of 65,000 km^2 there is altogether. So, we couldn't grow any other crops for food, and while it represents a considerable improvement over unassisted fermentation of sugar into hydrogen, it is still impractical on the grand scale of our transportation requirement.
How much generating capacity would be needed to run the system, by applying a voltage to the anodes?
The average is 300 mW/m^2 of electrode surface.
1 cm^2 corresponds to 42 mls of reactor volume, and the total reactor volume is 1.83 x 10^8 m^3.
Hence the total electrode area is: 1.83 x 10^8/42 x 10^-6 x 1 cm^2 = 4.36 x 10^12 cm^2, and since 1 m^2 = 10^4 cm^2, this amounts to 4.36 x 10^8 m^2.
Thus, the power needed is: 4.36 x 10^8 m^2 x 300 x 10^-3 W/m^2 = 1.31 x 10^8 W = 131 MW, which is not too bad, about 13% of the output of a typical power plant.
How much graphite is needed?
Anode chamber has a volume of 14 mls. If we assume spherical particles, their volume is:
4/3 x pi x (4.54/2 x 10^-3)^3 = 4.9 x 10^-8 m^3. To find the overall volume they occupy, it is helpful to imagine each one occupying a cube of side 4.54 x 10^-3 m (4.54 mm), for which the volume is:
(4.54 x 10^-3 m)^3 = 9.36 x 10^-8 m^3. The total anode volume is (14/42) x 1.83 x 10^8 m^3 = 6.1 x 10^7 m^3, of which, (4.90 x 10^-8/9.36 x 10^-8) x 6.1 x 10^7 m^3 = 3.19 x 10^7 m^3 is graphite. There is a graphite electrode inserted too, which occupies some of the internal space of the cell, but assuming the volume just determined and a density of graphite of 2.25 tonnes/m^3, this amounts to:
3.19 x 10^7 m^3 x 2.25 tonnes/m^3 = 7.2 x 10^7 tonnes or 72 million tonnes of graphite.
As a means to replace oil for transportation, the technology could not be scaled-up sufficiently for the task, certainly not to fuel the entire world's transport. The above figures only refer to the UK, and should be multiplied by around 20 to meet the needs of ca 600 million road vehicles as there are reckoned to be altogether. This would mean that 3830 tonnes x 600 million/33 million vehicles = 69,636 tonnes of Pt would be required, and yet the metal is recovered at a rate if about 150 tonnes per year, implying it would take 464 years to install the lot, using electrohydrogenolysis with fuel cells. This quantity is actually close to the reckoned world reserve of Pt, and so we all of that would need to be turned-over for this purpose, and none for jewelry, scientific apparatus or catalytic convertors to keep the internal combustion engine powered vehicles running "clean" while they were phased out by the new "hydrogen" technology.
It is an interesting paper, and the authors may be correct in their assertion that the technology might still prove useful for local fertilizer production, say, even if a full-scale transportation system based on hydrogen is never implemented (which it never will be). However, the scale even of this will be likely be very small, for the simple facts of limited resources and the otherwise massive engineering requirements.
 S.Cheng and B.E.Logan, "Sustainable and efficient biohydrogen production via electrohydrogenolysis," PNAS, 2007, Early Edition.
Friday, November 09, 2007
The term "organic farming" is a recent innovation, as opposed to its practices per se, which were those of the world's agriculture prior to the post WWII period, when chemical fertilizers were introduced to the soil. Until then, all farming was "organic" and was done without the employment of artificial "nitrogen" from ammonia or involving the routine use of synthetic pesticides. Modern "intensive farming" methods, such as we rely on in the industrialised nations, have been costed to consume 10 calories of energy in the form of fossil fuel (to provide fertilisers, pesticides and transportation fuel) for each calorie of energy that is recovered from the food itself.
Now, a strategy of localisation will inevitably reduce the contribution from transportation fuel, which is significant, but if pesticides and fertilisers are cut-out too, crop yields fall appreciably, meaning that fewer people can be fed per acre or hectare of arable land. It is a truth that "organic" farming is far more intensive in terms of land, if not in terms of energy. A major driver for the development of "chemical" farming methods was the plenty of chemical materials produced with the intention of military use during the war, and which it was decided could be put to benefit by turning them into agrochemicals.
I have mentioned Thomas (Robert) Malthus previously, who predicted more than 200 years ago that because population grew at a geometric rate (i.e. 2, 4, 8, 16...) but food production increased arithmetically (i.e. 1, 2, 3, 4...), the rate of reproduction would outstrip that of its sustenance, leading to mass starvation and an effective die-off scenario. This did not happen, in consequence of the "green revolution", which ironically is the opposite of the modern "green movement" since it refers to the many developments in agricultural technique that have been implemented since the 1960's, including the use of chemical additives to soil and to the produce grown on it. In consequence, world food production swayed-in with an increase of 250%, from greater absorption of nitrogen than occurs naturally, the growth of selected high-yielding crops like wheat and corn, and a greater mass of grain in the plants overall. For example, in 1950, an acre of land produced around 400 kg of wheat, but by 1950 this had risen to around 2000 kg/acre in South Asia but 4000 kg/acre in Europe and the US.
The downside of this is that it is necessary to provide more irrigation and hence an intensive infrastructure of dams and water-channels are necessary, especially to provide sufficient water during the winter period in order to grow an additional annual crop. Additionally, because more of the plant is consumed by humans, there is less residue left from it for animal feed. A mean energy intake for a human adult is reckoned at 2500 Calories (kilocalories) per day. A balanced diet is believed to correspond to about 60% carbohydrates, 12% protein and 28% fat. It is significant that during the green revolution the world has eaten more meat, meaning that the per capita land requirement is greater than would be the case to feed vegetarians. It has been estimated that 20 people can live entirely without animal products on the same area of land required by a typical meat eater. This may be a considerable overestimate, but certainly the carrying capacity of the earth is reduced if many of its inhabitants eat much more meat than they once did.
According to one calculation , the amount of land required to feed a single human is about one acre, following a mainly agrarian lifestyle, i.e. on the basis of pre-green revolution farming, without chemical enhancers. Since the total land area of the earth is about 150 million square kilometers, of which 10% is suitable for growing grains, another 10% for grazing animals on and a further 20% in the form of forests where animals can be raised, it may be deduced as a simple total that the sustainable world human population is:
150 x 10^6 x 100 hectares^2/km^2 x 40% x 2.47 acres/hectare x 1 acre/person = 14.8 billion.
However, the primary energy (food) input is surely the growing and grazing on a total of 20% of the planetary surface (we can't eat trees, although animals such as pigs can grub around the forest floor), suggesting a maximum sustainable population of nearer 7.4 billion, which is way short of the 8 - 9 billion presumed by 2050 and that contemporary farming methods will continue in perpetuity. Certainly there are other species on the planet, that do not exist purely in the interests of supporting the human race and the earth must support them too. So, would 30% of that land resource available for humans be a reasonable estimate? That leaves us with about
2.2 billion as the carrying capacity.
I am depressed. Either we will need to maintain the basic "forced methods" for crops by some means other than oil (and gas), to keep the present level of agriculture going (how?? coal??), or there will be a die-off in the world population, presumably through famine and wars over declining resources. Probably we will need to provide more of our diet directly from crops, rather than processing it through animals first, but even then, that only saves us perhaps a quarter-acre (from the per capita one acre), meaning the planet might support a maximum 3 billion, or less than half the present number. However, can we thus provide sufficient daily calories to fuel a population living far less sedentary lives, by grains etc. alone? There are just too many of us.
 "The World's Expected carrying capacity in a Post Industrial Agrarian Society." http://www.theoildrum.com/node/3090
 "Human Appropriation of the World's Food Supply
Wednesday, November 07, 2007
Many gas-wells are rich in NGPL. "Condensate wells" are gas-wells that are rich in hydrocarbons of the kind referred to vide supra. When they are first struck, oil-wells expel oil under the natural pressure of gas that they also contain, but the pressure drops as they are exploited and ultimately artificial pressure (e.g. from compressed CO2) must be applied, or pressurised water, among the range of enhanced recovery methods that are employed. There are also "dry-wells" which produce principally methane, but the relative composition of gas and liquid in a well varies enormously according to the local geology and origin of the hydrocarbon resource, overall.
To the tally of unconventional oil is then added oil (tar) sands, such as exist in massive quantity in Alberta, Canada; bitumens ("extra-heavy oil"), for example in the Orinoco belt in Venezuela; and oil-shale, as found for example as a large resource in Colorado. To make up the grand total of 3.7 trillion tonnes, as it has been proposed there is, oil from gas-to-liquids (GTL) and coal-to-liquids (CTL) processes are then costed-in. GTL is a useful means to produce high quality (clean) diesel oil from natural gas, by conversion to syngas and processing via Fisher-Tropsch (FT) methods into hydrocarbons. In the two CTL methods, coal can be converted (indirectly) to syngas and thence hydrocarbons using FT, or it can be hydrogenated (directly) to diesel fuel, based on the Bergius process, where coal powder is reacted with hydrogen under pressure as dispersed in a heavy hydrocarbon oil.
Deep offshore oil, such as that under the Gulf of Mexico, which can only be got by drilling through thousands of feet of water before the underlying rock is drilled, again through thousands of feet, is also accounted for under the heading of unconventional oil, as is true of the potential oil under the Antarctic and Arctic polar regions.
In this last May, the US Department for Energy began to speak of "liquids" rather than "oil", when making projections of exactly how much there will be available in the future, which looks like an ushering-in of the Oil Dearth Era. They predict that there will be a 400% increase in the production of unconventional oil in the US, from 2.4 million barrels a day to a daily 10.5 million barrels in 2030. This may be taken by cornucopians as a rallying-cry, in confirmation that peak oil is not important, in the sense that falling supplies of conventional crude oil will be more than matched by unconventional sources.
However, it is not a mere matter of how much "oil" there is in the ground (in some form or another) but how easy it is to get at, and frankly none of it can be obtained as readily as crude oil can. Bioethanol (corn ethanol) is a separate and much vexed issue, but most vexations rotate around an axis of costing-in other sources of energy used by the necessary agriculture and processing and that there must come the time eventually when growing crops for vehicle fuel conflicts with growing them for food to fuel humans and animals.
Making oil from tar sands is highly intensive in terms of other resources such as natural gas and indeed water. It has been proposed to build two nuclear reactors in Alberta to provide the energy for steam with which to drive the sticky bitumen out of the "sandy" mineral and to crack it into a suitable fuel. Then there are numerous issues surrounding pollution of the environment, and so it is not a happy solution on either count.
According to geological surveys, there are some 2.1 trillion barrels of oil (around twice what is believed to be left worldwide, in the form of recoverable conventional crude oil, if we believe the Saudi estimates of their reserves) present in shale rock in the US, but once again, extracting it is highly energy intensive, and bad for the environment too, since it will be necessary to strip-mine a huge area of wilderness to obtain the rock, which then needs to be heated to around 500 degrees C to get the oil out; then the resulting mountain-sized detritus of waste material, rubble and so on will need to be dumped somewhere.
Conventional oil is almost at $100 a barrel, and that makes many of these alternative approaches to unconventional oil appear attractive on economic grounds. It has been pointed out that the level of viability of these alternative technologies always seems to be about $10 above current crude oil prices. A few years ago it was $25 a barrel and now it is $75; in fact way below the latest $96 barrel. Hence on economic grounds, it would appear that anything goes! However, the EROEI (energy returned on energy invested) will ultimately decide whether a given source is "economic" or not, and clearly the answer is "not" when it takes more energy and other resources to extract oil from a given source than can be recovered from the oil itself when it is burned.
We should not be fooled by estimates of how much "oil" there is in the form of "liquids", the supply of which must inevitably fall. Our best option is to look toward means for reducing the amount of oil that we use, almost certainly by curbing the need for transport via a relocalisation of society, and other more efficient living strategies, rather than waging war on other nations or on the environment in an ultimately vain effort to preserve the status quo of excess.
(1) "It's no longer "oil", it's "liquids". By Jerome A. Paris. "The Oil Drum" blog, posted October 30th, 2007.
Monday, November 05, 2007
I have written on this subject in previous postings at some length, but the following points are salient. Hydrogen is not a basic fuel as are oil, gas and coal, but it must be produced artificially by liberating it from other elements, such as carbon and oxygen with which it is normally combined in nature, in the form of methane (natural gas) and water. These are, however, all energy intensive processes and almost entirely require the use of fossil fuels or nuclear power to drive them. Most of the world's current 50 million tonnes or so of hydrogen, produced annually to make fertilizers and to crack hydrocarbons, comes from "synthesis gas", a mixture of CO and H2 formed by reacting fossil fuels with steam in a process called "reforming", and so both chemical feedstock and heat depend upon them; hardly a "green" process, since CO2 is incurred both from combustion and by chemical stripping of the carbon component.
The ideal would be to make clean hydrogen by the electrolysis of water using renewable electricity (wind, wave, solar, hydro), but we need to go a very long way before that can be done on a large scale, although some think that enough new nuclear power might be installed to make the necessary electricity. I am skeptical that this can be implemented quickly enough, if at all, in the vast dimension that is demanded.
Even if we can make enough hydrogen, there is the issue of how to store, handle and distribute it. In comparison with liquid hydrocarbon fuels, gaseous hydrogen at normal pressure is highly voluminous, and hence it is necessary to handle it either as an extremely volatile liquid (with a boiling point of -253 degrees C, and only 20 degrees above absolute zero), or under high pressures. Either arrangement would require special technology to maintain it safe over time and to prevent leaks, since hydrogen forms highly explosive mixtures with air over a range of concentrations, and there would in any case need to be built a completely new infrastructure for generation, handling and distribution, once again within 10 years or so, and we haven't started yet.
For onboard storage of hydrogen as a fuel in vehicles, a considerable proportion of the energy actually contained in the hydrogen would be required to liquefy (30 - 40%) or pressurise (20%) the material into a "fuel tank". A fuel/tank weight ratio of 6.5% has been proposed below which the hydrogen strategy is inviable and there are numerous suggestions of porous solids into which hydrogen might be packed to occupy a smaller volume, e.g. zeolites, in some cases allowing an energy density close to that of liquid hydrogen but at significantly higher temperatures then -253 degrees C. Nonetheless, cryogenic cooling is still required. As an alternative, it has been postulated that the hydrogen might be stored chemically in the form of methanol. Indeed, one litre of liquid hydrogen contains 70.8 g of hydrogen at -253 degrees C, while one litre of liquid methanol contains 98.8 g of hydrogen and that is at room temperature.
The "methanol economy" could achieve holy grail status as a CO2 emission remediation strategy, by providing the carbon component of CH3OH, thus both preventing it from being released into the atmosphere and providing a vital source of fuel. Actual carbon-capture from atmospheric air on a degree of real significance is the stuff of the future, but capturing CO2 from power stations is feasible, which could be reacted with H2:
CO2 + 3H2 ---> CH3OH + H2O.
We are still left with the problem of making hydrogen on a vast scale and the infrastructure to do so does not exist at all. It is possible that rather than using preformed H2, it might be produced in situ, in the form of electrons and protons, by electrolysing CO2 in aqueous (water) media, so overall the effect is equivalent:
CO2 + 6H+ + 6e- ---> CH3OH + H2O.
However, the latter is difficult, since the reduction of (electron addition to) CO2 at the cathode (negative electrode) occurs in competition with electron addition to protons (H+) making hydrogen atoms and hence H2, the production of which competes with CH3OH formation. CH3OH is not the only organic product of CO2 reduction (either by electrons or H2), but also formic acid HCO2H and formaldehyde H2CO), although George Olah and his team at the Loker Hydrocarbon Research Institute at USC (University of Southern California) have patented a means to convert the latter to methanol, in an overall reaction where HCOOH provides "hydrogen" to reduce H2CO:
HCOOH + H2CO ---> CH3OH + CO2.
It is thought that the methanol would ultimately be "burned" directly in "direct-methanol-fuel-cells", but these currently depend on scarce supplies of precious metals such as platinum, as indeed do hydrogen fuel cells, and that appears to be a drawback on the technology. However, methanol can be converted to mixtures of hydrocarbons by reacting it over zeolite catalysts, for either purpose of making fuel (methanol to gasoline (MTG) process; invented by Mobil in the '70's) or as a feedstock for e.g. making plastics (methanol to olefin (MTG) process. In principle, many organic chemicals including pharmaceuticals might be made from methanol.
Most methanol is currently produced from natural gas (as is hydrogen) and so feeding the methanol economy by this means would impose further demands on a reserve that is, after all finite, as is oil; hence using CO2 as the carbon source appears perfect. Much of the current state of play in the field is heavily guarded by patents, and so I have not been able to tie-down the best efficiency so far achieved for CO2 reduction and nor do I know whether it is more efficient to do this with pre-prepared H2 or by electrochemical methods. However, my impression is that the latter are quite some way off and the process should be seen as a means for storing H2 made independently.
According to one report, the overall energy efficiency incurred in reducing CO2 with H2 and handling the resulting CH3OH is about 20%, and that is before the "fuel" has actually been used in some way. Therefore, while there would be considerable advantages met in handling liquid methanol at room temperature rather than H2 (either as a cryogenic liquid or a highly compressed gas), in terms of energy efficiency I doubt methanol is better than hydrogen, for which a value of nearer 40 - 50% might be accounted in terms of its manufacture by water electrolysis and the subsequent handling processes. Nor can it be, in the sense that installing a gargantuan new electricity generating capacity of similar capacity is necessary to underpin it.
On safety grounds, convenience of handling, storage and distribution (for which the existing oil infrastructure could be adapted), and that methanol might be converted to the numerous products that we presently get from oil (which is becoming more expensive all the time), as well as providing a clean fuel, the strategy holds much appeal. What it is not though, is a limitless supply of synthetic "oil", since CO2-derived methanol depends on electricity from fossil fuels and uranium, and may prove no more than a means for temporarily extending the illusion that the carbon-driven Western lifestyle is sustainable, which it is not.
(1) "Beyond Oil and Gas: The Methanol Economy," G.A.Olah, A.Geoppert and G.K.Surya Prakash. Wiley-VCH, 2006.
(2) "Novel CO2 Electrochemical Reduction to Methanol for H2 Storage," T.Kobayashi and H.Takahashi, Energy and Fuels, 2004, 18, 285 - 286.
(3) "Beyond Oil and Gas: The Methanol Economy," G.A.Olah, Angew. Chem. Int. Ed., 2005, 44, 2636 - 2699.
(4) "Renewable hydrogen utilisation for the production of methanol," P.Galindo Cifra and O.Badr. https://aerade.cranfield.ac.uk/bitstream/1826/1449/1/Renewable+Hydrogen-Methanol.pdf
Friday, November 02, 2007
The function of the metal is to provide a surface on which chemical reactions are catalyzed, and for example, toxic emissions from exhausts of NO2 (which contributes to ozone formation at ground level and to photochemical smog) are eliminated. In the specific case of NO2, which arises from the combination of atmospheric O2 and N2 drawn into internal combustion engines, at the relatively high temperatures within them, the catalyst simply reverses the process, and breaks it down to O2 and N2 again:
2NO2 --> N2 + 2O2.
How effective a catalyst is depends very closely on the actual area of the surface and simply, the greater that is, the more active the catalyst is expected to be. By using the metals in the form of nanoparticles, a smaller mass of metal is required to provide the same surface area is in current CC's, since the surface area scales roughly with the square of the particle diameter. Prior efforts to implement this technology had been unsuccessful because at the temperature of the exhaust, metal particles can migrate over the surface of the supporting ceramic bead and then coalesce (agglomerate) into larger particles, with naturally smaller surface areas and hence lower catalytic efficiencies. Mazda apparently have invented a means unspecified that can immobilise the metal particles by embedding them at fixed positions in the ceramic surface, which obviates the problem.
Now, the question remains of how useful this will be in the future. Oil prices have just hit $96 a barrel, and they will continue to rise. Inevitably, then, the cost of fuel or simply its reduced availability (since the rising cost will mirror the dearth of petroleum derived fuel, post peak oil) will begin to force cars off the road, thus cutting pollution in any case. When there is less fossil fuel to burn, carbon emissions will necessarily fall too. Can this technology be implemented quickly enough to make any real difference in comparison with the emissions-reductions that will be in any case implemented by the falling number of cars expected during the next 20 years say, as we slip into the age when cheap oil has certainly gone? Or do we still believe that the number of cars will rise interminably into the future; and if so, as fuelled by what means?
"Catalytic Converters go nano," Ned Stafford, Chemistry World, November 11, 2007, p16.