Whatever their motivation - be it energy independence for the U.S. or an attempt at fighting climate change for Europe - world governments are now heavily subsidizing biofuels. U.S. President George Bush pledged up to $150 million for work on cellulosic ethanol in his 2006 State of the Union address, and as recently as March 2007 he visited Columbia to convince the Brazilian and Columbian governments to become the "green fuel" centres of the world(1).
Biofuels, or fuels derived from living matter, however, are nothing new. Rudolph Diesel unveiled the first generation biodiesel-fueled engine which ran on peanut oil in 1898 at the World Exhibition in Paris, and Henry Ford intended his 1908 Model T to run on ethanol. Intriguingly, the major feedstock for the production of ethanol up to the 1930s was hemp, grown in the U.S. by political icons such as George Washington and Thomas Jefferson. Indeed, the first ethanol plant - a Ford-Standard Oil partnership - successfully operated in the Midwest until the 1930s, but tellingly, it collapsed because of the competition faced from lower-priced low grade petroleum-based fuels and negative marketing campaigns against hemp, led by paper and oil barons of the day (particularly, by William Randolph Hearst and by Lammont Du Pont)(2).
At the time, hemp, poised to supply everything from paper to renewable fuel, directly threatened the timber and petrochemical industries that Hearst and Du Pont were so heavily invested in. In their aggressive smear campaign they even managed to rename hemp marijuana - a term suggested to having come from the Spanish word mallihuan or prisoner - and Hearst-controlled newspapers published countless denigrating stories linking Mexican immigrants to crime and marijuana use. Eventually, and with the help of Hearst and Du Pont lobbyists, the Marijuana Tax Act of 1937, signed by President Roosevelt, effectively stopped any further investment in hemp and renewable paper, textile and fuel deriving from it. Ironically, and after a long delay, we seem to be returning to our original intention of using biofuels as the energy resource as the environmental toll exacted by the fossil fuel agenda leads to a renewed investment and R&D in biofuels.
How do these so-called new generation biofuels differ from the those envisioned by Diesel and Ford, and are they key to solving our current climate issues? Let's take a look.
First generation biofuels developed of Diesel and Ford rely on easily extractable sugars and oils from primary crops such as corn, sugarcane and palm or hemp. Their bio-conversion processes utilize antiquated fermentations based on conventional yeast strains or transesterification by alkali catalysts. Furthermore, the cultivation of corn, sugarcane and palm typically releases significant volumes of nitrous oxide - a more powerful greenhouse gas than CO2 - into the atmosphere due to the breakdown of large quantities of nitrogen-based fertilizers used in their cultivation(3). Other disquieting issues make first generation biofuels such as the U.S. ethanol and Columbian biodiesel problematic.
As subsidies as high as 90% drive the growth of the U.S. corn-based ethanol industry(1), flex-fuel vehicles are becoming more common and North American car makers attempt to push a greener agenda on consumers. But is this sort of fuel really "green"? Some critics contend that the production of the U.S. corn-based ethanol consumes more energy from fossil fuels than it yields when one considers the whole production and the supply chain (fertilizer/herbicide usage, machine use, processing and transportation)(1). Yet other studies estimate that a reduction of between 13-29% in greenhouse gas emissions may be possible when corn-based ethanol, as opposed to fossil fuel, is burned(4). As well, there are concerns about the impact of corn-based ethanol on the availability and price of corn for food - incidentally, a daily staple for many poor citizens of the world (including Mexico) - the so-called "fuel vs food debate". (It may be noted in this context that sugar cane-derived ethanol produced in Brazil produces a net energy gain, may be cheaper to produce than corn based ethanol, as the latter first requires conversion of the corn starch to sugar before fermentation to alcohol. The current U.S trade barriers, however, restrict its importation to the U.S.)
In the meantime, Europe, and particularly the U.K., are heavily importing palm oil from South American growing regions, particularly Colombia. The E.U., World Bank and Inter-American Development Bank, including USAID, are generously funding cultivation of this crop. This heavy investment is intended to divert the workforce from the cultivation of illicit crops such a coca and poppies while simultaneously producing abundant carbon neutral green fuels for the developed world. But can this strategy succeed in a country steeped in corruption? Alarmingly, it appears that palm oil plantations displace the rural workforce instead of employing it; the workforce that remains is hardly given a fair working wage and is frequently paid in surrogate currency (i.e. company credits) usable only to buy goods from their employers at inflated prices. And if you consider the environmental degradation which inevitably stems from cultivation of a monoculture and a concurrent loss of biodiversity, increased top soil run-off, stream-flow disturbances, destruction of vast tracts of virgin forest and savannah, human rights abuses, illegal land occupation by some palm oil companies, probable terrorist activities, money laundering and the highest assassination rate in the world for trade unionists (90% of those killed worldwide were Colombian workers)(1), the vision of Columbia as part of the "green fuel" centre of the world disintegrates.
The good news is that the second generation biofuels are produced through a more efficient bio-conversion step using lignocellulosic biomass, not simple sugars and oils. Feedstocks here may include agricultural and food processing wastes, trees, and various grasses that are converted to ultra-clean (minimal Sox and Nox pollutants) biofuel in elaborate biochemical or thermochemical steps. And depending on the choice of a microorganism the bio-conversion can yield cellulosic ethanol, bio-gas or bio-hydrogen. At the same time, genetic engineering promises to come up with more efficient microbial strains to yield better efficiencies. Currently, these second generation biofuels are projected to reduce carbon emissions by 90%, and by 2040 these could potentially replace up to 40% of all conventional fuels(3). This will only happen, however, provided a dramatic increase in R&D investment from the private and government sectors followed by a mandated legislation on their use.
The third generation biofuels are derived through genetically engineered (i.e. transgenic) energy crops, such as low lignin eucalyptus, poplar trees and high sugar content sorghum that thrives in acidic soil conditions. The added benefit here is that these so-called specialty energy crops yield comparatively more biomass, and their bio-conversion to biofuels is much improved due to high sugar and low lignin contents(3).
Importantly in light of the discussion above, the second and third generation fuels may be produced from biomass including waste rather than primary crops and can grow in areas inhospitable to food crops; as such, they do not place pressure on world food supplies. The second and third generation biofuels are also typically carbon neutral: they do not emit more CO2 during burning than what was originally absorbed by the biomass.
The fourth generation biofuels are based on engineering or breeding of energy crops that specifically absorb unusually high leves of CO2 (e.g. eucalyptus trees). Combined with carbon capture and sequestration, either pre- or post-combustion, this type of biofuel may result in a two-fold reduction in carbon emissions, or a bona fide carbon negative process, roughly defined as more carbon removed from the atmosphere than released.
The fourth generation biofuels may be also produced through fast pyrolysis - a technique that utilizes the burning or smouldering of biomass at 400-600 ?C in the absence of air. Its by-product, called biochar, used to be short-sightedly treated as waste, but it turns out that biochar may act as an efficient substrate for microbial populations which fix nitrogen, phosphorus, a variety of other nutrients as well as carbon and water in the soil. Remarkably, biochar, a.k.a. Terra Preta, has been used for more than 7,000 years by Amazonian civilizations as a means of doubling their agricultural crop production. Terra Preta is in fact a very effective carbon sequestration and crop enhancement tool: recent studies suggest that Terra Preta-improved soil could sequester up to 150 tonnes more carbon than unimproved soil, even before utilizing its improved fertility by growing cover crops (indeed, why not the fourth generation energy crops?) on it(5). Some studies estimate that amending only 10% of the biologically active agricultural land on the planet today with Terra Preta could help us attain carbon negative status in a relatively short time(6). So, it appears that producing biofuels via fast pyrolysis coupled to biochar-induced carbon sequestration and crop enhancement may also afford a true carbon negative process.
Although the second, third and fourth generation biofuels are not in widespread production today, with mandated legislation and continued investment in R&D, they very well may be in the next few years. But, as pointed out in the previous articles in this series, biofuels alone will not - can not - rescue us from our current state of planetary and atmospheric imbalance. We need globally agreed upon fuel efficiency regulations, widespread adoption of nanotechnology and other renewable energy systems, including sustainable agriculture, transportation, housing, waste management, energy generation and consumer education to be in a position, hopefully no more than in a few decades from now, to remove the excess of carbon that we pumped into the atmosphere during our fossil-fueled years. We need a concerted collaboration between the developed and the developing countries, so that each is held accountable, now and in the future, for their role in preserving the planet for the future generations. According to the official website for the United Nations Climate Change Conference in Bali (Dec 3-14, 2007), "What is needed is a breakthrough in the form of a roadmap for a future international agreement on enhanced global action to fight climate change in the period after 2012, the year the first commitment period of the Kyoto Protocol expires." With the world's citizens watching and demanding real action, will policy makers deliver or will one-dimensional narrow-minded economic motivations once again side-track us, as Hearst and Du Pont once did?
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Wilma Pretorius, Ph.D.. Biofueling the future. EnvironmentalChemistry.com. Feb 11 2008. Accessed on-line: 4/14/2021