The following has just been published in Science Progress, a popular science journal. Some of this has already been published on here, but I am now posting it in full for completeness:
C.J.Rhodes, Science Progress, 2011, Vol. 94, 1-9.
Political tensions in the Middle East once again remind us of the fragile dependency of the Western nations on imported petroleum, which have driven the price of a barrel of crude oil to above $100, as was the case immediately prior to the world economic crash in 2008. British motorists and owners of haulage companies flinch nervously in the face of rising prices at the pumps for fuel, feared to reach £2.00/litre if events fail to calm down, since supplies of crude oil from Libya, already cut by an estimated one million barrels per day from 1.6 million bpd, may fall to zero, leading to shortages and further hikes in oil and consequently fuel prices. Saudi Arabia has “promised” to make-up the difference by pumping out more oil, but there is doubt as to whether they have in fact sufficient spare capacity to do so, certainly not the light crude which is exported to Europe for refining into petrol.
There is, for that matter, some controversy over how much oil the kingdom does have in its reserves in total, which are thought might be far less than is claimed.1 The latter aspect is critical to the timing of “peak oil”, a phenomenon2 proposed as long ago as 1956 by Dr M. King Hubbert, a petroleum geologist working for the Shell Development Company. Hubbert’s predictions were made for the lower-48 states of America, that U.S. oil production would peak in either 1965 or 1970, depending on the volume of the reserve that he estimated, i.e. the total amount of oil that would ultimately be recovered given prevailing technology and oil-prices. Western civilization has been built literally on sand – underpinned by the desert sands under which most of the petroleum lies. Our position is thus precarious, resting upon an ability to import ever greater quantities of crude oil, to furnish economic and material growth. In the case of the lower-48 U.S. fields, oil production did indeed peak in 1970, as Hubbert predicted, and by application of similar reasoning the peak in world oil production can be expected to occur close to the present time.
The CEO of Shell has stated that the world will be unable to meet its demand for oil by 2015, while other commentators think so as early as 2012. Most of the major oil companies are investing in deep-drilling technologies to recover oil from less accessible regions of the Earth, including the Arctic, and it is likely that there will be further “accidents” such as occurred in the Gulf of Mexico, as new technologies and regions are developed to advance the map of as yet uncharted territory from which to slake our thirst for oil. Not everyone agrees with Hubbert, and yet the United States, once the world’s leading oil-exporting nation now imports 2/3 of the oil that it uses; a substantial proportion coming from the Middle East. It is argued that the Hubbert-peak, beyond which supplies of crude oil can be expected to fall forever, is an oversimplification; that it does not take account of new discoveries of oil, or of the exploitation of “unconventional” oil. In the former regard, world “peak discovery” occurred around 1965 and there have been no giant fields (i.e. those containing proved recoverable reserves of 500 million barrels or more) found since the early 1980s. Indeed, the global consumption of crude oil has exceeded the discovery of new quantities of it since the mid-1980s.
Since Hubbert identified2 a 40 year lag between peak discovery and peak production, this would also suggest that we are close to the point of peak oil, or have even passed it. Oil production is somewhat confounded by the reference to “liquids” rather than “oil”, which includes hydrocarbons that are recovered, sometimes in great quantity, from natural gas wells, which condense from the gas in liquid form once the pressure drops below the dew-point. The latter are also called condensates, and to their volume may be added natural gas liquids, hydrocarbons that exist in fields as constituents of natural gas but which are recovered separately as liquids, including propane, butane, pentane, hexane and heptane, but not methane and ethane, since these hydrocarbons need refrigeration to be liquefied. Thus the production of oil per se may be falling worldwide but total liquids have so far held pace with demand. Unconventional oil is a complex, vexed and multifarious subject, and strictly, the above liquids should be classified under this heading.
More “conventional” oil will certainly be recovered, and we are in no sense running out of it. That noted, it will be necessary to employ and develop new and better methods of extraction both to recover oil from e.g. the deep sea and under miles of salt or in polar conditions, and to get more oil from each well as a proportion of what it actually contains. The world proved oil reserves are close to 1.2 trillion (1,200 billion) barrels, to be compared with 6,300 trillion cubic feet of natural gas.3 Since the commonly used conversion factor is that 1 barrel of oil has an energy equivalent to 6,000 cubic feet of natural gas, the remaining energy reserves of the two kinds of fuel appear nearly equal. There is almost certainly far more oil in the ground to be recovered than this, but I stress it is the rate of recovery that is the more pressing issue, not so much how big the reserve is in total. If the rate of recovery of oil remains too slow to meet (rising) demand, we will experience a demand-supply gap within the next decade, a situation that has been described as “gap oil”.5 At best the maximum in oil production, peak oil, might be delayed, but once it occurs the gap will be enlarged.
There is also the issue of the quality of crude oil. Light sweet (low sulphur) crude is the most desirable as it can be easily refined into petrol, which is burned in spark-ignition engines, world production of which peaked in 2005. Brands of light sweet crude include West Texas Intermediate, Brent oil from the North Sea, and of course that from Ghawar in Saudi Arabia. Heavy sour (high sulphur) crude requires removal of the sulphur and catalytic cracking of the longer carbon chain molecules to shorter species in order to recover petrol from it in quantity. This necessitates more complex and expensive refining methods to process heavy sour oil, for which there is presently insufficient capacity worldwide. Hence new refineries will need to be built as the oil recovered in the future tends more toward the heavy kind, which is better used to make diesel fuel, requiring further a greater production of diesel engines.
Though as noted, natural gas liquids and condensates should be included as unconventional oil, more usually, especially in the media, the term is often used to refer to heavy oil, ultra-heavy oil (e.g. from Venezuela), synthetic oil from bitumen (principally the tar-sands in Athabasca, Canada), oil from shale, and oil made from coal and gas, the latter being termed gas to liquids processing (GTL). When all of these sources are reckoned together, the amount of available “oil” appears huge totalling 4.7 trillion barrels, and this has been taken to refute the notion of peak oil, or at least to mean that there will be no problem with meeting world demand for oil any time soon. However, this ignores the relative energy cost incurred in recovering each resource, usually termed Energy Returned on Energy Invested, with the awkward acronym EROEI, but which is also sometimes expressed as the Energy Profit Ratio, EPR. To place this into perspective, in the 1940s and before, EROEIs of 100 were common, meaning that 100 barrels of oil could be recovered using 1 barrel of oil’s worth of energy, but in the 1970s, e.g. in the North Sea, this had fallen to around 8. In the extraction tar-sand “oil”, the figure is closer to 3. Similar considerations apply to the extraction of “oil” by cracking kerogen present in shale (“oil-shale”), and it has been suggested that rather than using natural gas as the heat source to process both shale and tar-sands, local nuclear reactors could be built to generate the necessary thermal power. To process these materials not only requires a lot of energy but copious quantities of water, in the region of three barrels of water for each barrel of oil. Furthermore, the production of both tar-sand synthetic oil production and shale-oil defiles the environment.2
“Fracking” is a term that has been used frequently and condescendingly in the media recently, in the context of recovering gas from shale. It is claimed that 10% of Britain’s gas-requirements could be provided from shale and there is a pilot project about to be inaugurated onshore near Blackpool, otherwise famous as a holiday resort with its “illuminations”, “kiss-me-quick” hats, “sticks of rock” and “big-dipper” rollercoaster. The process of hydraulic fracturing (called frac’ing in the industry but fracking in the media) has been used since 1947 to fracture rock and assist the recovery of oil and gas. A hydraulic fracture is formed by pumping a fracturing fluid into a borehole drilled into the source-rock so that the downhole pressure exceeds that of the fracture gradient of the formation rock. The pressure causes the formation to crack, so that the fracturing fluid may enter and extend the crack more deeply into the formation. To keep the fracture open once the injection is complete, a solid proppant, commonly a sieved round sand, is added to the fracture fluid. The propped hydraulic fracture then becomes a high permeability conduit through which the formation fluids can flow to the well. Since the fluid contains various toxic materials, including hydrocarbons, benzene etc., there are environmental fears that these may leak out and contaminate e.g. aquifers from which drinking water is drawn. There are cases reported too, where methane can leak-out further afield into wells and tap-water in sufficient quantity that it can be ignited!
That such measures are being seriously considered appears as an abject demonstration of desperation. It seems clear that oil-supplies are going to fail at some point and sooner not later. Given the limited timescale, it is improbable that unconventional oil can be implemented in sufficient amount to take up the slack from conventional production on that 30 billion barrel annual equivalent scale. Agreed that all of that quantity does not need to be replaced in one go, but the ramping-up of unconventional production as the former declines will be unable to meet the shortfall, leading to a rapid decline in the number of the 700 million vehicles that currently grace the world’s roads. There is a further impact on aviation and rising demand for it, which already consumes almost one quarter of all fuel used in the United Kingdom, and is also unlikely to be met. Globalism will fade while "localism", involving a way of life based around small communities appears an almost certain default outcome.
World without Oil?
To, recapitulate, the current dependence of civilization on crude oil cannot be overestimated. While 84% of recovered crude oil is refined into fuels of various kinds, and three quarters of that amount for transportation alone, it also provides a raw feedstock for a plethora of industries, which produce an almost bewildering number of products ranging from plastics to pharmaceuticals. We are also entirely dependent on oil (and indeed natural gas for fertilizers) to produce practically all the food consumed in the world. The aspect of carbon-emissions, and the consensus that these will lead to unfavourable climate-change, further compels the search for low-carbon alternatives to oil since 38% of all the energy used by humans on Earth is derived from oil and fuels refined from it4; to be compared with 23% from natural gas and 26% from coal. Thus the origin of the majority of carbon-emissions for which humans are responsible is crude oil. In an effort to address the oil-problem, the substitution of oil-based fuels by biofuels has been explored, mainly derived from land-based crops. However, the area of arable land available to a single country and indeed the world overall is limited, and hence growing fuel-crops must inevitably compete with growing food-crops.
For example, if the United Kingdom were to cease growing food entirely, and turn over all of its crop-land to rapeseed (canola), it could only match, in the form of biodiesel around 17% of the fuel used nationally as derived from crude oil. In addition to considerations over their energy-content, there are vital differences in the properties of biofuels, e.g. biodiesel and bioethanol, from conventional hydrocarbon fuels such as petrol and diesel, which will necessitate the adaptation of engine-designs to use them, for example in regard to high viscosity at low temperatures, e.g. in planes flying in the frigidity of the troposphere. Raw ethanol needs to be burned in a specially adapted (high compression ratio) engine to recover more of its energy in terms of tank-to-wheels miles, otherwise it can deliver only about 70% of the energy-content, kilogram for kilogram in accord with its lower enthalpy of combustion (29 MJ/kg) than is typical for an oil-based fuel like petrol (gasoline) or diesel (42 MJ/kg).5 Most biofuels produced in Europe are made from plant oils such as rapeseed oil, in the form of biodiesel, with a smaller amount of bioethanol that is produced from sugar-beet. In the U.S. the situation is reversed and huge amounts of corn are turned-over to the production of “corn ethanol”. The ethanol industry in Brazil is mature, as made from sugar-cane which grows well there, with the U.S. as its major customer for exports.
While it is not thought that the Brazilian ethanol industry compromises land on which food crops could be otherwise grown, this is a strong objection made to the diversion of corn grown in the U.S. from the world food markets to making ethanol. Indeed, part of the huge increases in the price of basic staple foods has been blamed on the use of arable land to produce biofuels rather than to grow food. There are consequently shortages of rice and wheat, and a significant reduction in the market stockpile of corn, all of which contributes to a potential food-crisis particularly in developing nations, including China and India.5
Oil from Algae.
Of the various means that are being considered to provide alternatives to oil-based fuels, one is making biofuel from algae. There are many advantages claimed as are indicated in the bullet-points below, but most noteworthy are the quoted very high yields of oil that might be derived from algae per hectare, compared with that even from high-oil yielding plants such as palm, which translates to around 6 tonnes of diesel per hectare. In contrast, it is reckoned that some species of high oil-yielding algae might furnish annually perhaps 100 tonnes of biodiesel per hectare; an attractive prospect indeed, since on this basis an area say the size of the United Kingdom could fuel the entire world.5
*This can be grown in tanks to yield of over 100 tonnes of algal oil per hectare. Hence just 4,000 km2 would suffice to produce 40 million tonnes of biofuel, which is only 1.5% of the total UK land area.
*No need to use crop-land, hence avoiding competition with food-production.
* Grows well on saline water or wastewater, so no demand on freshwater, unlike biofuel crops.
* Can be “fed” nutrients from agricultural run-off water and sewage water, avoiding the need for mineral inputs of N/P fertilizers and cleaning the water/effluent to prevent “algal-blooms”.
*Can be “fed” CO2 from power-plants, improving algal growth and reducing carbon-emissions.
*Easier to process than other biomass, e.g. into CH4 , biodiesel, ethanol or hydrocarbons. *Biodiesel is more biodegradable than petroleum and fuel derived from it.
*50% of algae can be oil (lipid) c.f. 5 – 10% for land-based crops (e.g. soya, rape-seed).
*Reduces CO2 release by replacing oil-based fuels and absorbs CO2 when it grows, through photosynthesis.
*Can be used as a chemical feedstock; plastics.
*Algae (and other biomass) can be processed into organic chemicals, in a “biorefinery”, as a basis for a new “bio – organic” chemicals/industry.
*ExxonMobil, Shell, Unilever and many private companies are working on algae to make fuels and other products.
*One recent study shows that growing algae is most efficient as integrated with cleaning CO2 from power station smokestacks (or a cement plant) and N/P from sewage wastewaters.
“Artificial Cells” May Provide Souce Of Algal Fuel.
In a recent issue of Chemistry World is a report6 describing “the first synthetic cell.” What has in fact been done is to insert a chemically synthesized genome into a bacterial cell. The M.mycoides genome contains over a million letters of genetic code and current DNA-technology can deliver perhaps a few thousand units in one go. The team led by Dan Gibson and Craig Venter have exploited the ability of yeast to join together small pieces of DNA using enzymes. Grown in a petri dish, the synthetic bacterium looks almost identical to the natural version and can similarly self-replicate. For the development of tailor-made life, it is necessary to understand what each gene codes for. The longer-run might be that genomes could be designed, but achieving that is some way off. It is more probable that a simple artificial genome could be created that has the essential properties of a living organism.This could permit other gene circuits being introduced, for example, to produce biofuels or fine-chemicals. Dr. Venter’s company, Synthetic Genomics, intends to use the cell synthesis technology to produce modified algae cells from which to make biofuel.
The aim is to make a complete algal genome from which “superproductive organisms” could be derived. It is possible that the designer method can overcome some of the drawbacks involved with making fuel from algae, namely robustness and competitiveness of particular strains over other organisms, enhanced growth rate and yields of algal oil. The method might be the key to the widescale production of fuel from algae.
Looking For Algal Oil With Near Infrared Light.
A new method7 has been introduced for telling which strains of algae are likely to be any good for turning into biofuels based on Near Infrared (NIR) spectroscopy. The near infrared spectrum runs the range of wavelengths 800 – 2500 nm, and is therefore just below the region of visible light but above the usual mid-infrared, at 2,500 – 30,000 nm. The discovery of infrared radiation is attributed to the British-German astronomer William Herschel, who also wrote 24 symphonies. However, NIR only came to practical use in the 1950s as an analytical device. NIR is less sensitive than normal (mid) IR but can penetrate samples more easily meaning they need less analytical preparation and in the case of algae can be examined in their raw state. Algae vary considerably in their composition, and while some varieties contain around 50% of their weight of oil, others hold as little as 5%. Not only this, but the “oil” should contain a high level of fatty acids to be converted into biodiesel: triglycerides rather than phospholipids.
The NIR method is highly specific for the detection of different kinds of fatty acids and it is intended to develop a database of fingerprints for different fatty acid components in algal biomass, with which to analyse actual algae. The method offers the promise of a rapidly and precisely screening intact algae directly rather than the existing time-consuming, cumbersome and error-prone means for analyzing them. Algae To Fuels Under Pressure. The conventional route to biodiesel consists of extracting oil from plants and converting it to the methyl esters of fatty acids that are present in the lipid-components, known as triglycerides. These esters as a mixture constitute biodiesel, a specific kind of biofuel.
High oil-yielding strains of algae can be grown and dried and the oil extracted from the dry algal mass, before being similarly converted to biodiesel in a process called transesterification. Removing the water from raw algae is a highly energy intensive process, and to minimize the overall energy costs of biofuel production from algae, a process called hydrothermal liquefaction8 may instead be employed in which the algae are not dried but heated under pressure such that the water they contain acts as a chemical reagent and solvent that breaks-down the algal cells and converts not only the oil (lipid) but the sugar and protein component into fuels such as liquid hydrocarbons, gaseous fuels like methane and a complex material called “bio-oil” with a similar energy content to crude oil. Clearly, the design of engines will need to be adapted in order to use these alternative fuels directly, or they must be refined in a “biorefinery” along with those from other kinds of biomass.
In both cases of new engines or biorefineries, there will be huge new engineering required on a scale that can only be guessed at if algae really can be exploited to make a nation the size of the United States independent of cheap imported crude oil. Nonetheless, there is a U.S. consortium, the National Algae Association, that is actively seeking a future in which algae are grown on a large scale and converted to oil-alternative fuels. Certainly, it is likely that algae will become an essential component of the mix of means to keep transportation going by means other than crude oil. The claims of the NAA are undoubtedly true, that ultimately the supply of petroleum must decline, oil prices will continue to be volatile with knife-edge consequences for the world economy, and a wholesale industry based on algae would provide precious and needed jobs and economic development in the U.S. The approach could be introduced on necessary levels for all nations and even a village “pressure cooker” to provide algal fuels for small communities.
Biofuel From Algae: Different Prognoses.
There are differing prognoses9 regarding the imminence and feasibility of growing algae and converting it into biofuel to stave off the paucity of oil in the “post peak oil era,” as that final descent has been dubbed in some quarters. One fanfare heralds that the status quo of plentiful liquid fuels can be sustained even in the absence of crude oil, while the counterview is that the technology is “years away”. Certainly it is a better bet than other alternative schemes, particularly hydrogen, since prevailing distribution infrastructure – pipes, tanks and tankers – can be used since we are still dealing with liquid fuels, in analogy with those presently produced from petroleum. Liquid fuels are remarkable and without them the modern world would not have arisen in the form it has.
For transportation alone we need to find around 20 billion barrels worth of crude oil each and every year, and to ramp up that production year on year if we are to believe that the market forces will continue to dictate further demand – i.e. that capitalism is sustainable both as a practice and a philosophy. I doubt that perpetual growth is possible and the energy and resources curve is connecting its ends into a finite loop, set at an elastic limit bent only now in contraction. The hydrogen economy will not emerge in the immediate term10, since its fruition requires a massive supply of new “green” electricity and phenomenal new manufacture, handling and supply infrastructure. Even in a few decades time it isn’t going to happen, at least not on the scale of the crude oil economy – and there rests the crux of the problem. Algae at least can be grown, allowing sufficient installed new engineering, on a large scale that avoids using prime crop land in competition with growing food crops and there is no demand for freshwater since saline water does even better to promote the growth of certain highly oil-yielding algal strains.
Algae can be fed from waste-streams of CO2 from fossil-fuel power stations as a carbon elimination strategy and can also decontaminate groundwater, so there is a potential mix of environmental solutions in aid of a common goal of fuel “beyond petroleum” as is the new name for B.P. That said, it is going to take years, and the sooner we get going the better. It is likely that the best use of algal technology is to sustain smaller settlements of perhaps a few thousand grown in a “village pond” and processed for local use. There is still no means to maintaining global transportation and globalisation in the absence of cheap oil, and it is likely that the overall time-line for this gargantuan and conceptual transition can be drawn over several decades.
References.
(1) http://www.guardian.co.uk/business/2011/feb/08/saudi-oil-reserves-overstated-wikileaks
(2) Rhodes, C.J. (2008) The oil question: nature and prognosis. Sci. Prog., 91, 317.
(3) World proved reserves of oil and natural gas. http://www.eia.doe.gov/international/reserves.html
(4) Rhodes, C.J. (2009) Solar energy: principles and possibilities. Sci. Prog., 93, 37.
(5) Rhodes, C.J. (2009) Oil from algae; salvation from peak oil. Sci. Prog. 92, 39.
(6) Birch, H. (2010) The first synthetic cell. Chemistry World, http://www.rsc.org/chemistryworld/News/2010/May/20051002.asp
(7) Lewcock, A. (2010) Striking algal oil. Chemistry World, http://www.rsc.org/chemistryworld/News/2010/March/12031001.asp
(8) Demirbas, A. (2010) Use of algae as biofuel sources. Energy Conversion and Management, 51, 2738.
(9) http://debatepedia.idebate.org/en/index.php/Debate:_Algae_biofuel
(10) http://web.mit.edu/newsoffice/2005/fuel-2020.pdf
No comments:
Post a Comment