Can we Feed the World?

The world population of 6.5 billion is projected to rise to perhaps 8 - 9 billion by 2050. Simultaneously this period corresponds to the Oil Dearth Era, the inevitable consequence of the peak in oil production "peak oil" which is due any time soon, if it has not already occurred. Since much of modern agriculture relies on oil, the question begs of whether we will be able to feed such a swelling population, and if so by what means, or what manner of readjustments might prove necessary to meet the task?

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 [1], 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.


Related Reading.
[1] "The World's Expected carrying capacity in a Post Industrial Agrarian Society." http://www.theoildrum.com/node/3090
[2] "Human Appropriation of the World's Food Supply." http://www.globalchange.umich.edu/globalchange2/current/lectures/food_supply/food.htm
[3] www.beyondveg.com/billings-t/cal-par/calorie-paradox1a.shtml

Oil or Liquids?

Two camps stare at one another across the dividing gulf of oil supply. In one are the "peak-oilers" while the other contains the "cornucopians" (otherwise known as peak-oil deniers). The latter group argue that the Hubbert Peak analysis is invalid because supplies of oil, when they enter their inevitable phase of depletion, will be substituted by other sources, often referred to as unconventional oil or "liquids". One category of such "oil" includes "condensates" and "Natural Gas Plant Liquids (NGPL)". Condensates are very pure mixtures of straight-chain hydrocarbons in the range C2 - C12 (containing molecules with between 2 and 12 carbon atoms), cyclohexane (and other naphthenes) and various aromatic compounds (e.g. benzene, toluene and xylenes). NGPL are mostly ethane, propane, butane, isobutane and some C5 and higher homologue hydrocarbons.

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.


Related Reading.
(1) "It's no longer "oil", it's "liquids". By Jerome A. Paris. "The Oil Drum" blog, posted October 30th, 2007.
(2) http://en.wikipedia.org/wiki/Natural_gas_processing
(3) http://en.wikipedia.org/wiki/Natural_gas_condensate
(4) http://www.eia.doe.gov/glossary/glossary_n.htm

The Methanol Economy?

The term "Hydrogen Economy" is familiar by now, but there are numerous attendant difficulties which may not be overcome, or not in time to circumvent the energy-crash caused by cheap oil running short, signalled by a massive and inexorable hike in oil prices, as is now well underway. Notwithstanding the economic minefield the "Oil Dearth Era" will set, there are intrinsic technical problems in producing and handing hydrogen per se, if it is to be used on a scale of substitution equivalent to that for oil.

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.


Related Reading.
(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

Nanoparticles for Catalytic Converters.

The Mazda Motor Corporation has revealed a new class of catalytic converters which use between 70% and 90% less precious metals such as platinum than are required in current devices. Since around 40% of all platinum produced in the world goes into making catalytic converters (about the same as is used to make jewelry), this would suggest a significant reduction in the demand placed on a resource which presently exceeds its supply. In the new models, the metal is employed in the form of nanoparticles (i.e. with a size of perhaps around 10-100 nanometres. For reference, 1000 nanometres is one micron, and the width of a human hair is about 70 microns, so they are tiny).

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?


Related Reading.
"Catalytic Converters go nano," Ned Stafford, Chemistry World, November 11, 2007, p16.

UK Winter Electricity Shortages?

We have heard before that there may be an energy crisis in coming winters, and last year the warning referred to gas-supplies; this year it is electricity. We came through last winter without incident and I hope the same will prove true again. The National Grid has given an alert to the effect that there may well be a shortfall in its generating capacity, which mirrors a hike-up of gas-prices, and we British pay about 40% more for that commodity than our other European neighbours. Part of the problem is that a huge gas-terminal at Milford Haven (South Wales) will not be completed as soon as originally thought, in consequence of industrial action by contract staff and other problems.

The Minister for Energy, Malcolm Wicks, last week conferred with providers of electricity over fears that the UK is once again headed for ramping prices (now this did happen last winter although the lights stayed on), and power cuts in some regions, as indeed happened two years ago. The National Grid has, however, reassured ministers that no actual power blackouts are expected. Nonetheless, on the Grid website was a "transmission system warning" calling for another 300 MW of power to cope with the high-demand period between four in the afternoon and half past seven in the evening when, of course, people are cooking their dinners, watching tv, and putting the kettle-on during the interval in their favourite soap-opera.

Indeed, the situation for electricity supply to the Grid is a little precarious because of troubles at the now aging nuclear reactors in this country. I think 40% of the nation's electricity is made using gas, and so the Milford Haven depot not being completed might impact on the availability of it for this purpose. Indeed, no firm date has been set for when it will open, but it is clear that there will be no imports of liquefied natural gas there from Qatar to meet the winter's predicted demand.

There is also some doubt as to exactly how much gas will be brought in from Norway's Ormen Lange gas-field in the North Sea, via the Langeled pipeline, to the Easington depot in North Yorkshire, which opened last year and has provided some gas, but it is uncertain when it will be operating at its full capacity. When it is, 20% of the UK's gas requirement will be met via it, and the Milford haven depot is expected to carry another 20% in the form of liquefied gas. Our joyous plenty from the North Sea has been had and Britain is increasingly dependent on imports of gas from elsewhere. Hopefully there will be enough to keep the Christmas tree lights on in the coming festive season.


Related Reading.
"Rising fear of energy crisis this winter," By Terry Macalister, Guardian. http://www.guardian.co.uk/print/0,,331116810-103690,00.html