Biofuels and sustainable transport -- Can biofuels be produced and used responsibly?
By Renfrey Clarke
June 16, 2009 -- For governments and vehicle corporations, the charm of biofuels used to be the promise they held out of a ready-made solution to transport-related greenhouse gas emissions -- a solution that might simply be dropped in, while changing almost nothing else. Freeways, suburban sprawl, four-wheel-drive family cars -- everything could remain. Only the fuel on sale at service stations would be different.
Biofuels, the promise to the public ran, would be ``clean and green’’, an environmental zero-sum. Although carbon was released to the atmosphere when biofuels were burnt, this was carbon that had been there earlier, before being taken up by the plants from which the fuels were derived.
Underlying the biofuels push was an unlikely premise. Within a relatively few decades, human beings were predicted to finish burning the Earth’s accessible resources of petroleum, resources which had been built up over hundreds of millions of years. After that, biofuels were supposed to meet these consumption levels year-by-year out of the Earth’s current biological production -- which would also need to sustain the living environment and feed human beings. The scale of the contradiction was pointed out by British writer George Monbiot in a 2005 article:
In 2003, the biologist Jeffrey Dukes calculated that the fossil fuels we burn in one year were made from organic matter ‘containing 44x10 to the 18th grams of carbon, which is more than 400 times the net primary productivity of the earth’s current biota.’ In plain English, this means that every year we use four centuries’ worth of plants and animals.
The idea that we can simply replace this fossil legacy -- and the extraordinary power densities it gives us -- with ambient energy is the stuff of science fiction.
By early in 2008, reflections such as these -- along with a good deal of bitter experience -- were prompting a rethink. In economics as in nature, critics of biofuels were pointing out, everything is connected to everything else. When corn in the US was diverted from food markets and used to produce corn-ethanol fuel, world corn prices rose accordingly. That meant the Mexican poor went hungry.
The high corn prices encouraged farmers in the US Midwest to plant corn instead of soybeans. As soybean supplies tightened, soy interests in Brazil were prompted to plough up what had earlier been cattle pasture. And with pasture scarce, cattle ranchers in the Amazon cut and burned fresh tracts of tropical forest.
When such cascades of land use changes were taken into account, a 2008 study led by Timothy Searchinger of Princeton University and published in the journal Science concluded, the cost of using corn ethanol in greenhouse emissions per kilometre driven was almost double that of gasoline over a 30-year period. True, the carbon released when the ethanol was burnt had been in the atmosphere a few months earlier, not locked away in the Earth as with gasoline. But no fewer than 167 years would have to elapse before the savings made in this fashion would pay off the “carbon debt” incurred.
When peat-land rainforest in Indonesia was cleared for oil-palm biodiesel plantations, New Scientist reported in February 2008, the repayment time would be more than 400 years. Citing Princeton research, the Mongabay site in May 2008 reported that more than 55 per cent of oil palm expansion in Malaysia and Indonesia occurred at the expense of forests. At least in Europe, attempts are now made to ban imports of palm oil from recently deforested areas.
Adding to the misgivings surrounding biofuels has been a 2008 study by a team led by Nobel prize-winning atmospheric chemist Paul Crutzen. This found that nitrogen fertiliser used in growing biofuel crops was converted by soil microbes to nitrous oxide at around twice the rate previously thought. Nitrous oxide (N2O) is a greenhouse gas hundreds of times more potent than carbon dioxide. Crutzen and his co-authors estimated that for rapeseed (canola) biodiesel, the relative warming due to nitrous oxide emissions was 1 to 1.7 times the cooling effect due to saved carbon dioxide emissions. For corn ethanol, the figure was 0.9 to 1.5 times. Only cane sugar ethanol (0.5 to 0.9 times) was likely to have a net cooling effect.
Nevertheless, biofuels remain entrenched in agricultural and industrial practice in the European Union and the US. “A fourth of this year’s US grain harvest -- enough to feed 125 million Americans or half a million Indians at current consumption levels -- will go to feed cars,” Scientific American reported in May 2009.
An environmental atrocity, existing biofuels production is also economically disadvantageous for almost everyone except grain farmers and various sectors of the agribusiness, vehicle and energy industries. In essence, today’s biofuel industry survives only because governments, drawn by promises of a cheap fix for climate change and by the political lure of green credibility, have set mandatory targets for biofuel use and backed these targets with incentives.
In the US, the Energy Dependence and Security Act of December 2007 requires that annual production of ethanol, which was about 5 billion gallons in 2006, should reach 7.5 billion gallons in 2012 and 36 billion gallons in 2022. This latter figure corresponds to about 25 per cent of US fuel production at today’s consumption levels. The World Bank’s 2008 World Development Report calculates that more than 200 support measures in the US have a cost of US$5.5-7.3 billion per year, and provide ethanol with subsidies of 38-49 US cents per litre of petroleum equivalent. The European Union, meanwhile, has set goals for biofuel use in vehicles of 5.75 per cent by 2010 and 10 per cent by 2020.
Politicians and agroindustry in Australia have bought into biofuels too. The NSW government requires that petrol sold in that state include 10 per cent ethanol by 2011.
In the setting of modern capitalist society, biofuels are proving a destructive, costly fiasco. But if society were more rationally organised, could biofuels be produced and used responsibly?
The answer is a cautious “yes”. But not all biofuels -- only those with a verified “cooling” effect. And because of the potential damage, a truly green biofuels industry would need to be regulated closely in line with the best science available. There would be no room for the profit-at-all-costs mayhem of “free markets”.
Biofuels can only be a rational choice if they do not cause a loss of soil fertility, and do not compromise vital biosphere elements such as forests and rivers. Nor must they be allowed to displace important sources of food production. Also crucial is an understanding that on a world scale, biofuels can only play a minor part in ending net emissions from the transport sector. There is no way biofuels will ever power national transport fleets of today’s size and type. Even if the entire US grain crop were fermented into ethanol, Scientific American noted in May 2009, this would supply at most 18 per cent of current US automotive fuel consumption.
The transport systems of a sustainable future will rest heavily on public transport. Recent developments suggest that back-up will be provided by plug-in hybrid vehicles, yielding way progressively to purely electric cars and light trucks. For a time, production of biofuels will go largely to powering the hybrids on longer trips. Later, as electric-car batteries improve, the use of biofuels will increasingly be confined to specialised applications which require an energy source more concentrated than even the most advanced batteries can provide. These applications will include heavy trucks; agricultural machinery; locomotives, on rail lines with too little traffic to justify electrification; aviation, and shipping.
In large part, the biofuels used in a sustainable society will be produced from sources and using technologies quite different from those of today. At present, the main biofuel used is ethanol fermented from grain sugars and starches -- that is, from potential foodstuffs. As indicated earlier, a less flagrantly wasteful feedstock for ethanol than the corn mostly used in the US is the sugarcane that supplies the Brazilian ethanol industry. About half of Brazil’s sugarcane goes to biofuel production, providing about 15 per cent of the country’s liquid fuel supply.
Depending on the degree and type of land use change, the carbon “debt” incurred by sugarcane plantings can be modest; Searchinger in his earlier-quoted paper speaks of it being repaid in four years if the plantings are on former tropical grazing land. Sugarcane, however, is a voracious consumer of water and of agricultural chemicals, with the latter washing freely into streams. When sugarcane is planted anywhere except on level ground, it contributes heavily to soil erosion.
Better than extracting sugars and starch from plants in order to make biofuels, many scientists have surmised, is to find ways to process all or most of the plants -- including the cellulose that is among their main building-blocks. This is the thinking behind “cellulosic” or “advanced” biofuels, projected as the next stage in the development of the biofuels industry. The US National Renewable Fuels Standard, which sets out the requirements made of fuel companies under federal legislation, effectively mandates that of the 36 billion gallons of biofuels to be produced in the US by 2022, around 20 billion gallons must be of this “advanced” or “second-generation” variety.
Woody plants are composed mainly of lignocellulose, made up of the polymer lignin and of cellulose, which consists of long chains of sugar molecules. Numerous microorganisms feed on plant matter by secreting enzymes which break down the cellulose chains into simple sugars, which can then be digested. In the conventional production of cellulosic biofuels, plant matter is treated with enzymes to break down the cellulose in the fibrous cell walls. Yeast is then used to ferment the resultant sugars into ethanol.
Cellulosic biofuel production has a range of important advantages over “first-generation” processes. Since most of the plant is used, much more fuel can be produced for a given input of water and fertilisers. Often, cellulosic waste from food crops can be used as the feedstock. If the feedstock is purpose-grown biomass, plant species can be used which do not require prime farmland and need not displace food crops.
As of April 2009, four cellulosic biofuels facilities were recorded as operating in the US, with a further nine planned. Economically, however, “conventional” cellulosic biofuels remain a marginal proposition even with government incentives; the enzymes, in particular, are expensive. Research is now under way on new processes.
One line of investigation seeks to circumvent the high cost of the enzymes by using a thermal process to break down the biomass. Pyrolysis -- that is, heating in the absence of oxygen -- can be used to gasify the plant matter, turning it into carbon monoxide, carbon dioxide and hydrogen; these gases are then fed into a fermenter where bacteria convert them into ethanol and water. A variant of this approach makes use of the Fischer-Tropsch process, devised in the 1920s to make liquid fuels from coal. In this process, the gases are heated to high temperatures and passed over a catalyst, producing hydrocarbons that can be refined into petrol, aviation kerosene and diesel fuel. A sophisticated version of the Fischer-Tropsch process has been developed for use with plant biomass by the firm Choren in Germany, with commercial operation planned for 2012.
Thermochemical biofuels production has potential for being combined with the production of biochar -- that is, finely divided charcoal -- for soil improvement and carbon sequestration. In any event, some additional use has to be found for the large amounts of heat produced if the carbon emissions savings are to be substantial, and the process acceptably cheap. For this reason and others, current research on advanced biofuels concentrates mostly on biological processes. A particular goal is to find -- or engineer -- micoorganisms that both break down cellulose and secrete biofuels. While there have been no dramatic breakthroughs, a number of intriguing leads have emerged. Technology Review in December 2008 reported that the US firm Qteros was working with a microbe able to “dissolve cellulose into sugars and convert the sugar into ethanol, all in one step.” The company claimed to be “60 to 70 percent of the way to reaching its technology targets for commercialisation.”
Much of the eventual demand for biofuels is not expected to be for ethanol -- which has a relatively low energy density, is difficult to transport and store, and generally needs to be mixed with fossil fuels -- but for fuels made up of longer-chain hydrocarbons that can substitute for petrol, diesel and aviation kerosene. In November 2008 the British Guardian reported the finding in a Patagonian rainforest of a tree fungus that consumes cellulose and “produces a range of hydrocarbon molecules that are virtually identical to the fuel-grade compounds in existing fossil fuels.”
In the near term, most of the biodiesel that reaches the market seems certain to be produced using more established methods. Since the late 1930s, chemists have known how to turn vegetable oil into biodiesel through the process of transesterification, in which the oil is processed using alcohol and an acid catalyst. Modern diesel motors will run on biodiesel without modification, creating fewer harmful emissions than with petroleum diesel.
World output of biodiesel -- almost all of it obtained from vegetable oils -- is growing rapidly, but remains much less than production of bioethanol. According to World Bank figures, about 6.5 billion litres of biodiesel were produced in 2006, compared with ethanol output that year of about 40 billion litres. About three-quarters of biodiesel production took place in the European Union; most of this came from rapeseed (canola), at grievous cost in nitrous oxide emissions. Of other biodiesel production, a great deal is derived from palm oil, with the lamentable environmental costs noted earlier.
Biofuel processors are looking intently for sources of biodiesel that are cheaper than the present ones, and that if possible, draw less criticism from environmentalists. A good deal of attention has been turned to the developing world, and to previously little-known plant species that have potential for improvement as oil sources. In 2007, the Indian corporation Nandan Biomatrix was reported to have selected eleven species for study as biodiesel feedstocks.
Among the outstanding discoveries has been the bush, or small tree, Jatropha curcas. Native to Central America, jatropha is able to survive prolonged droughts; fixing nitrogen from the atmosphere, it grows vigorously in poor soils. Though toxic to livestock, jatropha has long been valued in Africa and South Asia for the superior lamp-oil that can be pressed from its large seeds. More recently, village mechanics have found that the oil also performs well as fuel for diesel engines.
The Indian government, the Yale Environment 360 site reports, has now “announced plans to subsidise an intensive program to plant jatropha for biofuels on 27 million acres of ‘wastelands’ -- an area roughly the size of Switzerland.” A new industry association, the Jatropha Sustainable Biofuels Alliance (JSBA), has identified more than 240 plantation projects, mostly in developing countries of Asia but also in East Africa and Latin America. In West Timor, foreign interests are to fund Indonesia’s first large-scale jatropha project on one million hectares of land. “We are observing a trend of major oil companies and international energy conglomerates entering the field with plans for large-scale investments,” the JSBA’s website notes. Large corporate investors to date include BP and the German vehicle firm Daimler.
Feeding enthusiasm for jatropha in the most recent period has been the discovery that its oil can be processed into a jet fuel that is compatible with aviation kerosene while also having a lower freezing point, lower specific gravity and greater energy density. The International Air Traffic Association has set a goal for its members to be using 10 per cent alternative fuels by 2017.
In the initial vision of the Indian government, the jatropha industry was not to distort the production of foodstuffs. Jatropha oil is inedible, and the plant was to be grown in place of rough pasture, or on otherwise unused land such as the strips bordering rail lines. The hunger of airlines for fuel, however, suggests that jatropha cultivation will now evolve quite differently.
Demand for land capable of growing jatropha will rise. Small landowners will come under pressure to sell out to plantation interests, and land rents will increase. Growing the new cash crop will become an economic necessity for tenant farmers who traditionally have produced food crops. Inexorably, the pressures of the market will shift jatropha cultivation from marginal and degraded land to prime farming areas where high yields are possible; studies in India have shown that while jatropha will survive in arid conditions, yields are typically five times greater when the plant is grown with irrigation.
The growing of jatropha for jet fuel, this suggests, could set off a cascade of food shortages and environmental destruction similar to that created by corn ethanol. The impact will be exacerbated if, as seems likely, jatropha plantations are granted credits under emissions offset schemes.
Agronomists might well protest that the real problem here is not jatropha. Growing the plant -- a deep-rooted perennial that requires virtually no fertiliser -- creates very few emissions to detract from the savings its use provides. In principle, jatropha should fit well into traditional smallholder farming regimes, since it improves soil nitrogen levels and is well suited to intercropping with food plants. The inedible harvest residues could be used in local pyrolysis plants to produce electricity and biochar, further raising soil fertility and food output while sequestering carbon. The biodiesel would supply local needs and allow national oil imports to be cut.
The real problem, it emerges, is capitalism -- and specifically, the power of global capital to short-circuit rational development in poor countries.
Meanwhile, plants such as jatropha and technologies such as cellulosic ethanol have no prospects for supplying anything like the offsets needed for “business as usual” to continue in the transport area.
At current jatropha yields, New Scientist calculated in August 2008, replacing world consumption of fossil-based jet fuel would require the plant to be grown on 1.4 million square kilometres, well over twice the area of France. Nothing, it is clear, will save the airline industry from having eventually to cut its operations to a fraction of their present scale.
The calculations for transport fuels in total are no more comforting. Assuming an average yield for biomass of 10 tonnes per hectare, New Scientist works out that “replacing all current transport fuel with (biomass-to-liquids) would require more than 10 million square kilometres -- an area bigger than China.” True, existing crop production and forestry create quantities of biomass that are often categorised as waste, and that might render the above figure less daunting. Biofuels researcher K. John Morrow in a 2008 paper cites “an authoritative and carefully researched study” of US resources which “documents that a billion tons of biomass is available for conversion to biofuel without serious economic, environmental or agricultural disruption.” This figure for the US, however, is still less than one-tenth of the global requirement calculated by New Scientist.
Even cellulosic biofuels, this makes plain, cannot be more than a modest extender for fossil-based liquid fuels. The world’s current internal combustion vehicle fleet is nowhere near sustainable.
The success of biofuel interests in having their products mandated by the US Congress defies logic on other counts as well. There is no reason to think that biofuels, even from cellulosic sources, will be able to compete in terms of economic costs or carbon emissions with electric vehicle technologies. The Australian newspaper in May 2009 cited “running cost differentials between an electric vehicle (2c/km) and petrol cars (10-14c/km).” A far more efficient and desirable way to turn biomass into transportation, it is now emerging, is to burn the biomass to create electricity that can be used in battery-powered vehicles. According to Technology Review in May 2009, a comprehensive US study has concluded that “on average, using biomass to produce electricity is 80 percent more efficient than transforming the biomass into biofuel. In addition, the electricity option would be twice as effective at reducing greenhouse-gas emissions.”
The present US biofuels legislation, this serves to illustrate, is not just a triumph for farm-state lobbyists, but also for vehicle corporations wanting to pay off their investment in current models.
On every count, it seems, biofuels are doomed not to measure up, except as fuel for transitional hybrid cars and for the heavy-vehicle applications noted earlier. Unless, that is, something exotic comes to the rescue. In the speculations of some scientists and engineers, microalgae have been cast in such a role.
In the first years of the century physicist Michael Briggs of the University of New Hampshire excited imaginations by calculating that biodiesel produced from microalgae grown in ponds covering 38,500 square kilometres could replace all the transportation fuels used in the US. Briggs’s main data were derived from theoretical figures calculated by the Aquatic Species Program of the National Renewable Energy Laboratory from tests in New Mexico between 1978 and 1996. Computations by the US Department of Energy have since suggested a larger pond area of 152,000 square kilometres, roughly equal to England and Wales.
In ideal circumstances, microalgae -- familiar to most of us as pond scum -- can double their mass in as little as six hours, and produce many times more biomass in the course of a year than any terrestrial plant. Numerous algal species are at home in brackish or even hypersaline water; grown in deserts using groundwater too salty for irrigation, they can be raised without displacing conventional agriculture. Selected species contain as much as 50 per cent of oils by weight. Even species that are not optimal as oil producers create a range of other saleable products, protein-rich animal feed among them. Algae flourish in nutrient streams from sources such as sewage plants, animal feedlots or agricultural run-off; if algal culture can be used to offset or reduce the cost of wastewater remediation, their fertiliser needs may be obtained free of charge.
The signs in the algal equations, however, are not all pluses. Briggs acknowledges, then ignores, the fact that the Aquatic Species Program was seeking uses for the carbon dioxide in flue gases from fossil-fuelled power plants. The impressive figures for algal biomass production published by the National Renewable Energy Laboratory were for ponds with carbon dioxide bubbled through them. When consuming atmospheric carbon dioxide alone, algae are well able to befoul swimming pools, but their biomass output is much too low to make harvesting worthwhile. The visions of algae ponds stretching to the horizons of the world’s deserts and allowing the car industry to produce unfettered are chimerical.
Most of the development work on algal biofuels carried out to date has, in fact, focused on recycling the emissions from fossil-fuelled power stations. Some of the most sophisticated algal bioreactor equipment produced so far, by a team at OhioUniversity, has been devised with the help of funding from the OhioCoalResearchCenter. There is a danger that algal sequestration of power station emissions will be used by energy companies as green-sounding propaganda for keeping fossil-fuelled plants operating, even though the net saving in emissions is rather modest. Algae are good at scrubbing nitrogen oxides from exhaust streams at any hour, but they photosynthesise carbon dioxide only in daylight; as a result, their effectiveness in reducing fossil carbon emissions round-the-clock is no more than about 40 per cent. It should also be remembered that while fossil carbon that is turned into algal biofuels and used in vehicles gets to be burnt twice, it still finishes up in the atmosphere.
The scale of the investment required if fossil-fuelled power plants are to have their flue gases scrubbed by algae suggests that the technology will not be widely installed, just hinted at in coal-company handouts. A typical 1000-megawatt coal-fired power plant, it has been calculated, would require no less than 5200 hectares of algae ponds to consume 40 per cent of its carbon emissions.
None of this is to say that algal biofuels should not be developed and used. There are numerous industrial plants -- steelworks, cement works and breweries among them -- that release carbon dioxide and that might be connected to algal bioreactors, with useful emissions savings. Perhaps the most promising concept involves integrating algal biofuel production with stockraising and the production of electricity and biochar from biomass. Such complexes would use flue-gas carbon dioxide from biomass pyrolysis to enrich algae ponds, producing animal feed as well as algal oil. The fodder would be used to raise livestock, whose manure would be bio-digested to produce methane for additional process heat, electricity and carbon dioxide. The nutrient-rich sludge from the bio-digesters would then fertilise the algae ponds. In Arizona, the firm XL Renewables is developing a related concept that would feed 7500 dairy cows, deriving its carbon dioxide initially from the fermentation of corn for ethanol, and later from fermenting part of the algae output.
“Closed loop” algae complexes of this type have considerable promise for carbon abatement. Not only is their efficiency in offsetting fossil fuel use high (XL Renewables projects an eventual figure of 10 to 1 for its algal oil and ethanol), but their output of meat is achieved at a fraction of the emissions cost of conventional stockraising. In principle, they can allow grain to be used as human rather than animal food, and grazing land to be turned over to timber plantations or natural forest.
Perhaps the most impressive feature of these schemes is their potential to be expanded without incurring major environmental costs. Their basic requirements are for low-cost level land, sunlight, brackish groundwater (or seawater), mild-to-warm temperatures, and a source of carbon dioxide that does not give rise to additional fossil fuel use. The latter source need not be in plant form; with due care, selected urban garbage might be used in combination with a pyrolysis process. So too, conceivably, might sewage sludge.
This picture fits well with stretches of coastline relatively close to various Australian cities. Areas such as the South Australian gulfs and the Western Australian coast north of Perth recommend themselves.
But is there anything in the prospects for microalgal culture to suggest that on a world scale, it might replace all or most of current petroleum fuel use? With algae-cum-stockraising complexes the size of whole countries? Merely to pose the question is to answer it.
Biofuels in Australia
On a global scale, biofuels are unlikely ever to have more than “niche” significance. Is the situation fundamentally different in Australia?
As scientist Mark Diesendorf observes in his book Greenhouse Solutions with Sustainable Energy, Australian landscapes with their warm temperatures and evergreen trees can be highly productive of biomass. Meanwhile, land area per head of population is unusually great. The effect is to make biofuels production, at least in principle, a more enticing proposition here than in most countries.
So far, investors have not been aggressive in developing this potential. According to a study by the Australian Bureau of Agricultural and Resource Economics (ABARE), biofuels early in 2009 were providing only about 0.5 per cent of Australia’s petrol and diesel supply, compared to a world figure the previous year of 2.8 per cent.
This indifference has not been for lack of government backing. Ethanol manufacturers in Australia enjoy an exemption from the federal government’s excise levy on petrol of 38.1 cents per litre, in addition to a similar customs duty on imported fuel ethanol. The 2008 federal budget included $15 million for research into second-generation biofuels over three years. Since 2007 the New South Wales government has mandated an ethanol content of 2 per cent in petrol sold within that state.
In NSW, and possibly in Queensland as well, government support for biofuel production is set to increase sharply. NSW legislation passed in April 2009 provides for the state’s ethanol mandate to increase to 6 per cent in 2010 and to 10 per cent in 2011. The NSW government also reportedly plans to implement a biodiesel mandate of 2 per cent, rising to 5 per cent when sufficient supplies become available. According to the Australian in January 2009, the Queensland government plans a 5 per cent ethanol mandate, to be introduced by 2010 and to be supplied mainly through the fermentation of molasses, a low value by-product of sugar refining.
Until now, most of the ethanol required for the 2 per cent mandate in NSW has come from a plant at Bomaderry, south of Sydney. Owned by the Manildra Group, the plant processes wheat starch, a by-product of milling operations. According to the crikey.com website in January 2009, the “E10” -- that is, 10 per cent ethanol -- mandate in NSW will require the direct use of an estimated 2.5 million tonnes of grain each year. Projections have been made for at least four new ethanol production facilities in NSW, and for the Bomaderry plant to be expanded. A further plant, processing grain sorghum, has begun operating at Dalby in Queensland. In drought years, the Australian on January 5 quoted biofuels analyst Geoff Ward as saying, the NSW and Queensland ethanol mandates could consume as much as 40 per cent of the national grain crop.
Over the full cycle of ethanol production and use -- that is, including the fossil fuels used in feedstock growing, transport and processing -- the E10 mandate is predicted by ABARE to result in no more than minor savings of carbon emissions. With the ethanol content of fuel at 10 per cent, the savings per kilometre are calculated at between 0.7 per cent (for ethanol from wheat) and 4.2 per cent (for ethanol produced from molasses, while using sugar refinery wastes to generate electricity).
There is no indication that when ABARE worked out these figures it factored in the most recent evidence concerning nitrous oxide emissions and crop fertilisers. Nor does it seem to have taken into account the effects of sharply cutting Australian supplies to world grain markets. As with US corn, the reduction in Australian grain exports will raise world prices and spur the destruction of forests for additional grain-growing in countries where controls on land clearing are weak or non-existent.
In mandating ethanol use, legislators in NSW have argued that they are looking toward the advent in years to come of “second generation” ethanol-from-cellulose processes, expected to sharply reduce the diversion of food grains to biofuels production. But for most of the next decade, if not longer, the net effect of the ethanol mandates will be to put large amounts of extra greenhouse gases into the atmosphere. The world environment would be better off if motorists in NSW and Queensland were to continue filling up with conventional petrol.
For biodiesel in Australia, the prospects are considerably more encouraging. Modern diesel engines are about 40 per cent more fuel-efficient than petrol engines of equivalent power; replacing petrol-engined with biodiesel-driven vehicles can thus bring important emissions savings.
At present, most biodiesel sold in Australia comes from tallow -- that is, animal fats, now usually considered abattoir wastes -- and from recycled cooking oil. For these reclaimed feedstocks, the emissions savings are impressive. In a 2007 report produced for the oil firm Caltex, the CSIRO concluded that the savings with used cooking oil were 87 per cent, and with tallow 76 per cent. “Palm oil from existing plantations” was rated at 80 per cent, but guaranteeing that consignments of Malaysian and Indonesian palm oil are not tainted by rainforest destruction has proven difficult. Canola (rapeseed) oil rated a lowly 49 per cent even, it appears, without increased nitrous oxide emissions being taken into account.
According to ABARE, biodiesel production throughout Australia in 2007 amounted to 59 million litres, about 0.3 per cent of total diesel use. The NSW government’s biodiesel mandate, the Australian reported in January 2009, is to come into force later in the year and will initially require about 80 million litres annually. Most of this is expected to come from a facility near Maitland in the HunterValley, run by the firm Biodiesel Industries. Sources are to include cottonseed and canola oil.
The best options for expanding Australian biodiesel production sustainably involve tree crops in the north of the country. In Central Queensland in particular, large areas which once supported dense scrub have been cleared for cattle-raising. In the “top end” of the Northern Territory gamba grass, introduced as a superior cattle feed, has fed bushfires so hot as to kill the native savannah woodland across wide areas. As in Australia as a whole, the cattle industry in both regions needs to be scaled back, since the enteric methane emitted by cattle is a dangerous contributor to global warming. New land management systems are needed, and tree plantations for biodiesel could be part of them.
An obvious species for such plantations is Jatropha curcas. The plant has long been established in northern Australia, where its toxicity -- it is known locally as “bellyache bush” -- has caused it to be declared a noxious weed. High-yielding male sterile clones are available, and might be grown with government consent. The crop residues, which like the leaves are poisonous to cattle, could be pyrolysed to make electricity and biochar.
A better candidate than jatropha in many settings might be the honge tree (Pongamia pinnata), which is native to regions from India to northern Australia. Nitrogen-fixing, undemanding as to soils, and highly tolerant of salinity, honge sends its taproot as deep as ten metres, allowing the tree to flourish in monsoonal regions with a brief rainy season. In plantation conditions, yields of its inedible oil can outstrip those of jatropha and oil palm several times over. The residues from the oil-bearing seeds provide a protein-rich animal feed.
With appropriate support and training, graziers might well agree to switch from cattle-raising to running biodiesel plantations. In Central Queensland, such an industry could also provide alternative work for coal miners idled as moves to reduce carbon emissions see mines shut down.
In theory, plants such as jatropha and honge could be cultivated widely acrossnorthern Australia. They have potential for providing indigenous communities with an economic base. According to Pacific Renewable Energy, which has researched honge in collaboration with the University of Queensland, a “good” yield of honge oil is 5 tonnes per hectare per year, with an “optimal” figure of 9.66 tonnes. At “good” levels, enough honge oil to substitute for Australia’s annual diesel use of about 13.5 million tonnes could be produced on an area of plantations measuring about 270 by 100 kilometres.
Amid the vastness of northern Australia, this area is not particularly large. It represents, for example, less than half the area of brigalow woodland that was cleared -- mainly for cattle grazing -- in Central Queensland between 1960 and 1990. There would be no need for further native vegetation to be destroyed for biodiesel to be produced on the necessary scale.
Honge trees take up to 15 years to yield at their full potential. If biodiesel is to contribute to a swift reduction in Australia’s transport-related emissions, feedstock sources that can be developed more rapidly will be required. Here, the most promising field of research is microalgae.
At least ten universities and government-funded research bodies around Australia have microalgae programs. One of the most advanced is that of SARDI, the South Australian Research and Development Institute. In alliance with FlindersUniversity, SARDI in December 2008 was planning a proof-of-concept facility to combine biofuel production with that of high-value co-products such as nutraceuticals. The project, SARDI reported, would include a facility on TorrensIsland, near Adelaide, to incorporate “four 50-square-metre raceway ponds that will utilise nutrient rich saline water from the PortRiver estuary, carbon dioxide from adjacent power plants and solar energy.” As explained by Associate Professor Wei Zhang of FlindersUniversity, producing biofuels would only cover the basic costs of the process; profits would have to come from value-added products: “Biodiesel is worth around one dollar a litre; pharmaceutical grade Omega-3 fatty acids can fetch up to $100 a litre.”
It is not hard to imagine how production of algal oil might take place in integrated fashion on an industrial scale. Low-value land would be used, quite probably coastal samphire flats close to infrastructure. Production of biochar from crop wastes or trees such as mallee would provide energy and a portion of the carbon dioxide. Water would come from brackish aquifers or sewage too saline to be reclaimed for irrigated agriculture. Quite likely, the algae would be grown not in broad ponds but using the trough-form equipment developed in the US by XL Renewables, and available commercially. After the oil was extracted, pigs, poultry, rabbits and perhaps fish such as barramundi would be raised on the protein-rich residue. Manure from the livestock would be bio-digested, and the resulting methane burnt to produce additional energy and carbon dioxide.
The process would be remarkably self-sufficient; the major inputs, apart from the crop wastes or other biomass, would be phosphorus fertilisers, trace nutrients, and possibly stockfeed supplements. None of the technology employed would be really novel, and much of it could be bought “off the shelf”. Given the political will, large complexes of this type could be operating in Australia in less than a decade.
Australia’s consumption of fossil-based diesel fuel, it emerges, might well be replaced with biodiesel within a relatively short time-frame. What about consumption of petrol, currently about 19 billion litres per year? Could the advent of suitably cheap cellulosic processes allow petrol substitutes to be “dropped in”, and existing Australian transport patterns to continue with minimal disruption?
Significant research into cellulosic processes is now being mounted in Australia, centred in Queensland and concentrating on ways of making biofuels from bagasse, the fibrous residue left after sugarcane is crushed. At present, bagasse is largely burnt to produce energy for sugar mills and for feeding into the electrical grid.
October 2007 saw the setting up at Queensland University of Technology of the Syngenta Centre for Sugarcane Biofuel Development. As described by the Australian, the centre involved “a collaboration between the Queensland government, Swiss agribusiness giant Syngenta and Brisbane-based biotechnology company Farmacule.” Funding was reportedly in the region of $5 million.
The quantities of sugarcane wastes available in Australia are nowhere near enough to replace the country’s petrol consumption, but what about cellulose from fast-rotation tree crops? Does Australia have enough suitable, already-cleared land to grow the quantities required, and to do it without affecting food production? Many of the calculations here have been performed by Mark Diesendorf, who on p. 152 of his book concludes:
…it is possible that more than half of Australia’s liquid fuels could be supplied from about 10 million hectares of dedicated land.
If we allow three million hectares for biodiesel production, this suggests that about 17 million hectares of biomass tree plantations would be needed to keep the country’s petrol-driven vehicles on the road.
According to the Australian National Resource Atlas, about 13 per cent of Australia’s land area, some 100 million hectares, has been cleared of its natural vegetation. In 2005, the Australian Bureau of Statistics records, the country’s cropped area amounted to 26.7 million hectares. From the other 70-odd million hectares of cleared land, might 17 million suitably productive hectares be found? Almost certainly it could, especially since global warming, by drying out marginal grainlands, will force wheat farmers off large areas which will then be available for drought-resistant tree crops such as mallee.
Producing enough petrol substitutes to allow “business as usual” on Australia’s roads, this suggests, is literally possible. Whether this represents a rational use for biomass is a separate question.
If the goals motivating policy are not to keep petrol-engined vehicles on the road, but to reduce carbon emissions by as much as possible while providing Australians with transport, different strategies will be followed. The cellulosic feedstock will be pyrolysed to biochar, while heat released in the process will be used to produce electricity which, by the time the biochar is sequestered in soils, will be emissions-negative. Even if the electricity is then used to charge battery-driven private cars rather than to drive trams and trains, the emissions savings compared to taking the cellulosic-fuels route will still be substantial.
The research effort now going into producing cellulosic biofuels from bagasse poses particular dangers: if the process is shown to be profitable, pressures will mount for sugarcane to be grown specifically to feed the biofuel facilities. Sugarcane is a heavy consumer of water, which might otherwise be used to irrigate food crops. Cane growing also requires abundant use of nitrogen fertilisers, the nitrous oxide from which can cancel out most of the gains in terms of greenhouse emissions.
How might the appropriate choices surrounding biofuels in Australia now be summarised? Biofuels must, of course, be considered within a general framework that involves the accelerated replacing of petrol-driven cars with a mix of public transport and electric cars, with biodiesel-powered hybrids as an interim stage.
Within this context, vigorous work should go into researching and developing algal biodiesel complexes. The same should occur in the case of oil-producing trees such as honge and jatropha. Mandates for biodiesel use should be introduced, and depending on research results, steadily expanded as feedstock becomes available. The use as feedstock of edible vegetable oil from crops such as canola or oil palm, however, should cease.
The fermenting of ethanol from molasses -- which otherwise would be used mainly as cattle feed -- might well continue. No further facilities, however, should be built to produce ethanol from grains, and the ethanol mandates should be repealed. Biochar pyrolysis, on the other hand, has genuine promise, and depending on further research, should be developed both as an adjunct to algal biodiesel production and because its own by-products include a useful bio-oil. If the prognoses for biochar remain favourable, plantations of tree crops on historically cleared grazing land should be fast-tracked. But the resulting biomass should not be used to produce cellulosic petrol substitutes in any major way. If produced at all, these fuels should be a heavily taxed self-indulgence of classic car buffs and miscellaneous petrol-heads.
That would be a rational way to proceed. But in current political circumstances, events promise to unfold quite differently. As the present economic crisis ends, demand for biofuels to meet mandated levels, in Australia and abroad, will increase rapidly. High prices can be expected to spur an assault on savannah regions around the world, and this will be reflected in Australia too. So far, the savannah belt of northern Australia has been one of the few such regions in the world to have its biota remain substantially intact. But as the biofuels industry becomes wealthy and politically influential, it can be expected to exert pressure for the more fertile and well-watered parts of Australia’s savannah regions to be cleared for huge new oil-tree and biomass plantings.
Those prospects might seem cause for environmentalists to reject the whole concept of biofuels. But technologies should not be ruled out merely because capitalism in its search for profit uses them in perverse and destructive fashion.
The task before environmentalists is to assess new practices critically, on the basis of their genuine merits. Combined with this must be a readiness to campaign for rational choices in the interests of humanity and nature, whatever the pursuit of profits might dictate.