U.S. Brazil, Ethanol

Hi Inflixion,Thanks for posting this. Biofuel production is an interesting topic - and one that has some relevance for my current projects (more on this below).For those who are unaware of what biofuels really are, they are ethanol or diesel fuel equivalents produced through processing of various plant species. About 600-700,000 barrels of biofuel are produced globally each year. In large scale production (mostly Europe and North America), crop fields are planted specifically for the production of fuel: wheat, corn, or sugar beet, and rapeseed (for biodiesel), among others including soybean, are all used in this process. In small scale production (used in certain areas of the developing world), sugarcane, sugar beet or African oil palm (Elaeis guineensis) is used either directly or as post-process waste for production of ethanol and biodiesel.Although not a bad system, there are some limitations inherent in large-scale production and use of the type envisioned in the article including:” Energy yield. Biofuels yield only a fraction of the energy that an equivalent amount of gas does. For instance, bioethanol yields ~21 mj/l, whereas gas yields around 31 mj/l. This loosely translates into a requirement that more ethanol is needed to produce the same amount of “go-juice” than can be produced by gas.” Scale. Intensive monoculture is required to produce any reasonable amount of crops that can be directly converted to fuel. For instance, the highest yields produced in Europe from fully mechanized sugar beet production gives about 50 metric tons/ha. Conversion of beets into ethanol yields about 0.11 m³/ton, or about 110 liters/t. This is NOT sustainable without massive inputs (fertilizer, pesticides, mechanization, etc). Corn yields about 170 l/ha, soybean around 450 l/ha, etc. This is primarily why the basic cost of the final product is considered so high. You get a very small net energy produced per unit cost. Doing the math, we'd have to convert a HUMUNGOUS (that's a scientific term ) amount of current agricultural land into biofuel production to make even a minor dent in the amount of petroleum used. Since at least some land has to be used for actual food production, the only alternatives would seem to be taking over "currently unproductive land" (like rainforests) to produce the needed fuels.Contrasting with small-scale production, especially using biowaste or small-scale culture (like rapeseed or E. guineensis), and foregoing the high degree of inputs required by large-scale production, biofuels ARE highly environment-friendly. There is a project in Nicaragua, for instance, where post-process sugarcane waste (after the cane is shredded, mashed, mulched and otherwise beaten to death) is used to produce sufficient ethanol to provide the majority of power for Leon (the country’s second largest city). Since biofuel production is a mature technology, the critical constraint on small-scale production - equipment cost - has been removed. It is now down to the point where a small group of local farmers - especially as an adjunct to an integrated farm program - can afford to purchase the equipment needed (it really isn’t all that complicated on small-scale, just labor-intensive - and cheap labor we gots lots ).Which brings me to the reason I know anything about this stuff. The Foundation I work for has been actively seeking ways to become energy self-sufficient in our combined development and conservation programs in the Ecuadorian Amazon. Our facilities overall currently use solar power to provide ~60% of our energy requirements (which includes a satellite-based internet, WAN, and other high-tech goodies that make the Foundation unique in the region). Unfortunately, we rely on diesel power generation for the remainder (there are constraints on the amount of solar power we can produce - it IS a rainforest, after all). In addition, most supplies, visitors, etc, are brought in by diesel or gas-powered canoes. I was asked to consult on the environmental impact of a biodiesel project that would become part of our integrated farming program. We were considering importing E. guineensis, as well as investigating some native palm species for generation of biodiesel (including Elaeis oleifera, Orbignya barbosiana and Astrocaryum vulgare). Because of yield (almost 6000 l/ha! - 60 times the yield of sugar beet), the Foundation was really leaning toward the exotic African palm but were concerned about the threat from an invasive. Turns out there’s no problem (ABE: at least under the mitigation schema they propose). They have 30 ha of former agricultural land that is entirely unsuitable for reforestation of which they currently use ~15 ha for their “demonstration” integrated farm (I put demonstration in quotes because the project has been spectacularly successful - it provides almost all of the agricultural produce consumed by both the technical high school and the 2200 ecotourists who visit annually with zero external inputs - one of the only projects that DIDN’T work was the methane capture project for cooking, and that was because one of the damn hogs got loose and rampaged through the system, destroying most of the equipment). They plan on producing about 10 ha of oil palm, which will provide nearly 100% of the fuel needed by all the facilities. The palm grove will not be a monoculture. They will be intercropping with everything from legumes to cacao, plantain and banana, and possibly chonta palm (Guilielma insignis - used for food and construction).To make a long story short - as long as biofuels projects are limited in scale, there is very little environmental impact, and in fact they can be extremely effective and low cost. However, I have extremely strong reservations about attempting to replace a significant fraction of the world’s petroleum consumption in this manner. Both yield and space requirements - especially for more popular but less productive in fuel terms (and more environmentally damaging overall) crops like corn monoculture - would seem to be more likely to exacerbate deforestation, ecosystem degradation, pollution, etc, than be a help. I agree in principle with the bioscience article you cited. Given the vast deforestation in Malaysia, Indonesia and Thailand where rainforest has been converted to oil palm production, the examples we have of non-sustainable large-scale commercial production of biofuels doesn't bode well. Edited by Quetzal, : clarification

Well, the simple answer is pretty much what kuresu mentioned: corn production in the US is one of the most highly subsidized crops we produce. IOW, rather than pay farmers basically to NOT grow corn (which is the case today), the government will pay them to grow corn for biofuel. It really sucks (another good scientific term) for this as it has one of the lowest yields while requiring some of the highest inputs. In addition, large scale corn production is one of the worst crops as far as leading to nitrification of local watersheds goes. Not only because of the requirement for pesticides and nitrogenous fertilizers, but because of the basic natural history of corn itself. Yes and no. This is sort of the "classic" model, to the point where most high school and undergrad textbooks keep repeating it. It really depends on how it (agriculture) is done. Without getting into the different tropical soil types (oxisols, antisols, etc), the relative truth of this observation depends mostly on the type of forest and where it is located. For instance, varzea-type forest (seasonal flooding) located on sandy soils watered by drainage from the Guyanean Shield (so-called blackwater rivers) are very nutrient poor, whereas the same forest type located on soils watered from the high Andes (so-called whitewater rivers) are nutrient rich. Nutrient-poor soils require much higher inputs for large-scale agriculture. The oil palm plantation I mentioned we're considering will be located in a high-nutrient environment (whitewater varzea).In any event, it's less a question of nutrient content than it is of moisture retention. One of the main problems with already nutrient-poor soils is that once you clear the forest (which has evolved to very quickly recycle nutrients back into the biomass), it doesn't take long before the soil heats up and loses all of its moisture. The soil bakes literally rock hard, any remaining nutrients are leached with amazing rapidity, and any kind of large-scale agriculture is pretty much contraindicated. Even nutrient rich tropical soils can be leached very rapidly if cleared. However, an agroforestry system where a signficant fraction of the canopy is retained (which retains moisture) can yield an immense amount of production, essentially in perpetuity if combined with intercropping or other sustainable ag programs. Of course, this doesn't work with shade-intolerant plants like corn (or highly mechanized agriculture) - which would be another good reason to pick a different approach to large-scale biofuel production.{ABE: There are a bunch of other factors, including the physics of raindrop impacts - no joke - that effect moisture retention of tropical soils. But the above is the short answer.} Yep. If it ain't done right, that's the only approach - and the resultant environmental degradation would be severe, IMO. I find it highly unlikely that this approach would be cost effective - no matter how high fuel costs go. Which is another thing to worry about. We're typically fixated on intensive, mechanized, vast-scale monoculture. I can't see any way this could work in the neotropics. Edited by Quetzal, : clarification

Well, I'll try. I'm not an agronomist or plant biologist. The way it was explained to me was that basically corn is a nitrogen "sink". You've got to remember that what we call corn has no "natural" equivalent. Unlike barley, rice, wheat, manioc, etc, corn is an entirely "created" crop. This essentially means that unlike most other crops there are no associated microbes that help corn with nitrogen uptake (see, especially, plants like the Leguminosae). Which means, roughly, that the only way corn - which requires a huge amount of nitrogen and/or nitrogenous compounds - can meet its requirements is through osmotic action at the root level. Which means, in turn, that the concentration of nitrogen in the soil has to be very high. Finally, this means that the rate of nitrogen leaching in anything but a totally contained environment (say, a laboratory), is extremely high. And all that excess nitrogen goes straight into the local watershed or water table. This is one of the reasons intercropping corn with legumes, for instance, is so effective. Unfortunately, you can't do that with large-scale monoculture (obviously). I'm probably missing some bits, but that's the way I understand it. I seem to remember that there's a eutrophic "dead zone" at the mouth of the Mississippi about the size of New Jersey caused by algal blooms fed by nitrogenous run-off from ag production up river. I could probably dig up a reference on that if you want.

A pox on all physicists.

Here's a sort of short, very general discussion:Carlisle E, 2000, The Gulf of Mexico Dead Zone and Red TidesHere's a more detailed but very readable discussion from the USGS:Goolsby DA, Battagin WA, 2000, Nitrogen in the Mississippi Basin-Estimating Sources and Predicting Flux to the Gulf of MexicoAnd here's a more technical (albeit shorter) discussion:Scavia D, Rabalais NN, Turner RE, Justic D, Wiseman WJ, 2003, Predicting the response of Gulf of Mexico hypoxia to variations in Mississippi River nitrogen load, Limnology and Oceanography, 48:951-956If you need any more, let me know.