Last Revised October 31, 2008
A Quick Profile of Tobacco as a Bioenergy Substrate
Let's begin by defining biomass tobacco and summarizing some of the main reasons I believe it should be seriously considered as a bioenergy resource.
Tobacco biomass is simply one or more conventional tobacco varieties planted very tightly together rather than spaced in neat little rows. When grown as biomass rather than for tobacco products, tobacco has some remarkable properties as a potential bioenergy resource, which we'll cover in detail on this web site. After reading the evidence and arguments that follow, perhaps you'll agree with me that tobacco biomass is, everything considered, potentially far superior to all other purpose-grown bioenergy plant resources including corn and sugar cane.
Whether grown conventionally or for biomass purposes, tobacco is remarkably rich in all of the natural sugars and other carbohydrates, and also is almost unique among plants because it produces complete and well-balanced human food and medical grade protein.
The fact that smoking commercial so-called "tobacco" products has killed tens of millions of people has evidently totally obscured tobacco's potential for cost-effective bioenergy production, both for ethanol and, more promising, as a high-yield substrate for production of biogas. The time has come for the veils of illusion around tobacco to drop away and for tobacco biomass to be fully investigated by the bioenergy community.
Like most plants tobacco is mostly water - between 80-90%. This means that its dry weight, the actual amount of biomass produced by the plant, is between 10-20% of total green weight production right out of the field. So let's say that we are producing 100 tons of fresh, green biomass tobacco per acre (as you will see this is a conservative figure) which means that we will be getting a total of between 10 and 20 tons of solid, dry weight. While this may seem like a very high per-acre yield to you if you're familiar with biomass literature, as you'll come to see this is actually a very low yield for biomass tobacco.
PLEASE NOTE: since you have to leave lanes for harvesting the biomass tobacco, the yield-per-acre figures used throughout this essay refer to acres of biomass, not acres of land. My calculation is that growers will have to leave @ 20% of an acre of biomass for access lanes.
- Of this dry weight of tobacco biomass, approximately 20% will be pure, natural sugars, or approximately 2-4 tons of sugars per 100 tons of green weight.
- Another 10% or so will be starches, or about 1-2 tons of starch from a 100 ton crop.
- About 20% of the dry weight will be mixed proteins, which break down into what is called Fraction 1 and Fraction 2 protein, or between 2-4 tons of pure protein per 100 tons of fresh, green weight.
- Also, since the tobacco plant is about 40% cellulose, dry weight equivalent, we'll be harvesting between 4 & 8 tons of very low lignin, easily fermented or digested cellulose per 100 tons green weight.
In summary, Tobacco biomass can be produced at well over a hundred tons per acre, using either hand labor or simple machinery, on land that is unsuitable for food crops, and that biomass material can not only provide low cost bioenergy, extracted as biogas or ethanol or both, but also after that energy has been produced, pure unadulterated food grade protein, along with medical grade protein and other economically valuable byproducts, can be extracted from the fermentation tank or digester sludge. Then that sludge, which is very high in available nitrogen, and other nutrients and trace elements, can be returned to the soil.
All of these properties, in combination with other factors to be discussed below, mean that tobacco biomass may well be the key to the low cost decentralized, low carbon footprint bioenergy resource that many people have been seeking for many years.
BackgroundI began the journey of discovery that has resulted in this web site many years ago when, along with several friends, I was starting the Santa Fe Natural Tobacco Company. At that time I was also researching the alternative properties of tobacco and ran across some research papers by Dr. Ray Long of North Carolina State University. Ray had been looking into the production of food-grade protein for human consumption from tobacco leaves and, in order to make the process economical, he was raising tobacco as a biomass crop rather than as a conventional tobacco crop planted in widely-spaced rows.
I was interested in what he was doing not because the notion of producing high quality protein from tobacco, but because I was interested in alternative energy and it was clear to me that biomass tobacco might be a great source for ethanol. Being able to grow so many such prolific pIants so close together, and to be able to harvest so much rich green high-sugar plant material per acre, seemed to me to have all kinds of possibilities.
I corresponded with Dr. Long for several years, and he and I cooperated in several experiments where he supplied the biomass tobacco and an experimental ethanol facility in Western Virginia did trial runs, ultimately demonstrating that biomass tobacco not only could be fermented to produce ethanol, but that the economics of doing so were compelling.
This research showed that tobacco grown as biomass could produce well in excess of 100MT/Acre, with high percentages of digestible sugars and other carbohydrates, and rich in both F1 and F2 proteins. It also demonstrated that there is no inhibition of the biofermentation process by use of a tobacco substrate, which strongly implies that there shouldn't be any inhibition when tobacco is used as a biogas production substrate or co-substrate since biomethanation is an inherently more stable process than fermentation. Furthermore this series of successful fermentation runs put to rest the most common objection raised by people on first hearing of the idea of tobacco biomass as a bioenergy feedstock - the fear that the nicotine might somehow inhibit the process of fermentation, which it emphatically does not. ( For a detailed description of this project click here ).
Ultimately these experiments and their unequivocal outcomes came to nothing because the Reagan administration pulled the rug out from under all kinds of alternative energy projects, and in a very short time the team involved dispersed and the experiments were forgotten. Why the tobacco biomass experiments at NCSU were quietly shelved we'll never know, but maybe it's for the same reason that no reference to tobacco as a biomass resource shows up in a search of Oak Ridge National Laboratories (ONRL) bioenergy database - the world's premier database in the field and supposedly an impartial collector of data. Only an institution with tremendous reach and power could shut down a major university research project and ensure that no reference to it ever appeared in a public access databaseof the stature of ORNL.
The economics of ethanol production from biomass tobacco remain compelling, with the probability of production of 1500-2000 gallons per acre at a fully accounted cost of less than $0.75 per gallon, including offsets for income from valuable wastestream products, but without any subsidies. This is ethanol that can be produced from straight fermentation of biomass tobacco material fresh from the field, and the biomass production doesn't replace any food crop either. And, since the US automobile fuel system is already set up for cars to use ethanol, perhaps this really is the best use of biomass tobacco production. Biomass tobacco has so many advantages over all other in-use and proposed ethanol feedstocks one can only wonder at why it hasn't yet been given full-scale trials.
For full details on biomass tobacco/ethanol production click here Also you can look over some of the original tobacco biomass and protein documents here.
However, as I kept thinking about the possibilities inherent in hundreds of tons of biomass tobacco per acre, harvested by simple technology or even by hand, I eventually came to the conclusion that the best approach to using biomass tobacco was not to produce ethanol, but to produce tobacco biomass as animal feed first, and after producing large amounts of animal protein using ultra-low cost tobacco biomass as part of the feed mix, to produce pipeline-quality biogas energy from their manure, mixed with fresh biomass tobacco slurry as a co-substrate.
If my very limited and easily demonstrated set of assumptions regarding the feeding of biomass tobacco to animals prove true or, if not, then digesting it directly as a co-substrate with any existing biogas substrate which has already been proven feasible - if any of my small set of assumptions that remain unproven are correct, then it will be possible, among other things, for small, independent groups of people like villages and towns in remote areas to produce for themselves, free of outside resources except the initial biogas/electric technology, both ultra-low cost, high quality animal protein as well as virtually unlimited quantities of pipeline-quality gas energy, all essentially for the cost of the community's own labor.
On a somewhat larger end of the scale of potential, biomass tobacco appears to make possible and economic the conversion of existing nuclear plants to biogas plants, and to produce vast amounts of high grade food in the process. Sweet irony.
I believe that this potential is all real, quite simply because so much high sugar biomass material can be produced per acre at ultra low cost from Nicotiana Tabacum - ordinary tobacco - the supposed scourge of mankind. What wonderful, cosmic laughter we will all hear if it turns out that tobacco is not only the answer to our energy needs but in the process enables the world to abolish hunger without the need for either big capital or high technology.
You might also find it amusing, as I do, that I am also the author of The Cultivators Handbook of Marijuana, which I first self-published in 1969 and which was the first 'grow your own' book. I intended the book as a revolutionary act to liberate people by empowering them with vital information they weren't getting anywhere else, and offering them perspectives they might not have thought of before regarding issues like freedom and liberty.
So here I go again, and this time it's biomass tobacco as a potential food and energy solution for the world. Marijuana and Tobacco. I'm either stuck in a serious rut, or suffering grandiose delusions. Or perhaps I'm onto something, and I'm betting that's the case. After reading on, I'm betting you may think so too, dear reader.
OK. For a look at some of the scenarios that have occurred to me as I've contemplated the compelling possibilities of biomass tobacco, let me take you through my reasoning, and the supporting evidence, for the use of tobacco biomass to produce biogas energy, a relatively simple equation which I believe has the potential to transform much of the world as we know it.
Biomass Tobacco For Food & Energy
Some revolutionary changes in both renewable energy costs and food production could occur if it were possible to produce very high quality animal feed for $5 a ton just about anywhere in the world. That's because at $5 a ton for animal feed, the cost of energy produced from manure gathered from animals feed this ultra-cheap food is effectively zero.
With animal feed at $5 a ton, grown anywhere in that vast country, China could abandon the use of mercury-contaminated brown coal and fuel its huge economy with natural methane gas while providing bountifully and profitably for every human mouth; Mexico could abandon use of high sulfur oil and make its northern deserts the source of wealth and energy; Africa could electrify and feed its most rural communities simply by adding a few hectares of community-farmed biogas tobacco, increasing their animal herds, and feeding a low cost 500KW digestor/generator with manure and tobacco biomass; Ukraine, Bulgaria and Romania could shut down their badly designed nuclear reactors and restore their prosperous private farming communities; Japan could turn to overseas energy farms rather than domestic nuclear reactors sited in earthquake zones; India and Pakistan could feed their people and literally electrify the subcontinent with ultra-low capital costs; prosperous but energy-dependent countries like Australia, South Africa, Brazil and Argentina could be energy independent; America's small towns in the Midwest and south could revive and prosper and the lost investment in nuclear generating capacity could be fully recovered. All of this and much more could happen if there was a way to feed penned animals so cheaply that methane gas from their manure could generate electric power, and other forms of energy at costs competitive with conventional natural gas.
And there's the problem. Quite simply, it is the cost of animal feed alone that is the limiting factor which keeps energy from manure-based methane non-competitive with energy from natural gas and other fossil and nuclear sources.
The technologies for producing methane from animal manure, and energy from the methane are well-established, but with corn and other quality livestock feed costing between $100 and $300 per ton in the US, and comparably high in the rest of the world, the cost of energy produced from penned animal manure is, and very likely will remain far too expensive to be competitive. In order to be a competitive source of pipeline-quality methane gas, electricity, methanol fuel, and associated chemical feedstocks at 2008 U.S., European or Asian market prices, penned animals would have to be fed high quality feed costing well under $50 a ton. This just isn't possible with any of the conventional animal feeds, so economically competitive high volume production of biomass-based methane energy & fuel remains a dream.
And please keep in mind as you browse this paper that it is not necessary that the model for tobacco-based bioenergy involve feeding animals first,then producing methane from their manure. It has already been shown in European lab experiments that direct digestion of tobacco by biomethanation is not only possible, but produces superior gas yields. These experimental results are scheduled for full-scale field trials in Spring 2009. I am simply advocating that feeding animals with fresh biomass, then harvesting energy from their manure, may offer the optimal set of economic and social benefits if things work out that way.
I've had this dream for nearly 30 years, and am dedicating this site to offering both personal and university-based research that I believe shows that biomass tobacco can be a superior non-bloating animal feed, high in complete protein, sugars and readily digestible cellulose, which can be produced with little/no investment on even poor quality soils in most climates around the world for the equivalent of $5 a ton using low technology. - even hand labor can be used very effectively to harvest biomass tobacco. Production costs for this high quality feed have been well-demonstrated by university research to be so low that if it is shown to be a viable feed in any one of several possible forms, then cattle, pigs, sheep, and goats can be raised for their energy production value alone, with the animal protein produced by such herds as a paid-for byproduct of energy production.
We already know, through field trials conducted by the Farm Bureau in Kentucky and North Carolina, that the green sludge remaining after protein has been extracted from tobacco biomass is palatable and accepted by ruminant animals. We also know, from trials conducted by Leaf Protein International in the 1980's, that the protein extracted from tobacco leaf is pure, tasteless, and has the protein efficiency rating equivalent to both soy and milk. This means that it will be accepted by ruminants if added to their feed as a protein booster. What we don't know - yet - is whether or not fresh green biomass tobacco can be fed directly to animals either before or after ensiling. At this moment ( Fall 2008) trials are underway in Europe that will establish this as a viable possibility or not.
In addition, still-confidential lab trials by a major European biogas technology company have established (Summer 2008) that tobacco is an excellent co-substrate for biogas production, with no inhibition of biomethanation by any residual nicotine in the material, so even if additional trials prove that it is not possible to feed animals directly with biomass tobacco it can still serve as a high-yield, ultra low cost substrate and the proteins extracted from the residues of the biogas production process can indisputably be used for animal feed at revolutionary low cost. So, whatever the route taken, biogas production from biomass tobacco is in my mind without doubt an economically viable path to low cost bioenergy and food production.
The fact that this basis for this revolution in energy and food production is tobacco, grown and harvested using proven biomass production techniques, may be so startling that many will read no further; but if you do, I welcome you to a discussion of the great possibilities which may flow from these unexamined properties of the tobacco plant, which Native American people rightfully consider one of the most generous gifts from the Great Spirit to his human beings.
Copyright © 2007 by Bill Drake
All Rights Reserved
Welcome to this site. Limited permission is hereby granted to individuals to print a single hard copy of these materials for personal reading, and to individual teachers and health professionals to make limited copies of these materials for distribution to students or patients. With these limited exceptions, none of these copyrighted materials may be printed or distributed, nor incorporated into any other body of work for distribution of any kind in any medium, without prior written permission from the author, which will be readily provided in most cases. Please contact bdrake@ktc.com
The use of plant biomass for energy is nothing new. It probably began when ancient humans burned wood to keep warm. Biomass is simply a name for the total amount of plant material in a particular location - the total plant materials in a forest, or growing on an open field, or covering a mountain.
Since the 1960's there has been a lot of interest in the use of plant biomass as an alternative energy resource, and many different kinds of plants have been used to produce ethanol for vehicle fuel, to fuel boilers for electricity production, and to feed penned animals and produce methane gas from their manure.
There have been literally hundreds of alternative energy projects involving plant biomass of one kind or another, but so far very few projects have managed to produce energy at a cost that makes it competitive with conventional energy.
In the case of ethanol, for example, it has proved impossible to produce enough corn per acre, at a low enough cost, to make corn-based ethanol competitive with gasoline as a vehicle fuel. The same has been true of all other ethanol biomass feedstocks - they either cost too much per ton to produce, or if they do produce high tonnage at low cost, they aren't rich enough in sugars for cost-effective conversion to ethanol.
When plant biomass is used to fuel boilers to produce heat or electricity, it is usually slow-growing wood or sugar cane waste, which cannot be produced fast enough, at low enough cost, or over a wide enough area, so coal, gas or oil remain the conventional choice. Many different experiments have been made to produce fast-growing species, to pelletize fast-growing non-woody plants as fuel - but none have broken through the simple cost-per-unit barrier between biomass fuels and conventional energy sources.
Conventional methane production from animal manure has a somewhat more competitive cost structure, largely because it captures a waste stream and recovers energy from it, so energy costs are offset somewhat by revenues from the animal protein production. However, because of the costs of feed, energy production has to remain a secondary output and must be "subsidized" by animal production - in other words, because of the cost of the conventional animal feeds, the methane gas produced by using these conventional animal feeds can't stand alone and compete on cost with natural gas.
In addition, because methane is being produced by facilities whose primary purpose is animal protein production, usually pigs, rather than energy production, these facilities tend to be environmentally undesirable. A facility whose primary purpose is energy production would have a completely different internal structure and environmental impact, with positive outcomes for all concerned parties.
A number of people are promoting the use of hemp for biomass energy purposes, and while I applaud the political sense that such a campaign makes, there are very basic reasons why hemp cannot be used to produce economically competitive biomass fuels, primarily because it is relatively low in sugars and leaf volume and because its cellulose is protected by very thick lignin walls - which is why hemp produces a superior fiber. Industrial hemp producers have been fighting a difficult battle for acceptance for many years, but perhaps when biomass tobacco is added to the mix the benefits of such production will appear irresistible.
Clearly in an integrated energy/food/fiber production unit a producer would want to have both biomass hemp and biomass tobacco acreage, enabling them to produce energy from both hemp and tobacco, plus high quality animal fiber from penned goats and sheep fed tobacco, plus high quality plant fiber from the hemp. A co-op of such producers could integrate vertically with a regional textile production facility while sustaining the entire membership's operational overhead through co-op energy sales.
So when it's all said and done, there is really only one reason why some kind of biomass energy resource hasn't yet been able to replace oil, natural gas, or nuclear energy - everything tried so far costs too much. And there's really only one reason why it costs too much - because nobody has yet demonstrated a plant biomass material that can be grown at low enough cost, in large enough quantities, across a wide enough range of environments, with high enough energy potential to compete worldwide on a fully accounted energy cost-per-unit basis with oil, natural gas, and nuclear fuel.
This is a brief introduction to some of the many remarkable characteristics of tobacco. In some ways it's a very simple story. Tobacco biomass sugars and proteins cost so little per-unit to produce, and are of such high quality, that it should be possible to produce low-cost, high quality ethanol and methane fuels on a small scale which are extremely competitive with oil, natural gas, and nuclear energy. Tobacco biomass appears to me to be an ideal candidate for a wide range of uses which have the potential to increase energy and food availability worldwide, reduce energy costs and increase quality of life, to conserve fossil fuel reserves and replace nuclear energy, to create new economic opportunity, enhance the global environment, and empower small-scale family farm production units.
That's what the rest of this part of the site is about - the various thoughts and ideas which have occurred to me as I've explored the potentials of this remarkable plant. It isn't that the factual content of any of this information has been hidden. Any tobacco scientist, and in fact anyone familiar with tobacco at all knows that it is very high in sugar. Many people know that it's very high in protein too, and that wild animals as well as insects will devour a field of tobacco, given half a chance.
Here are just a few of the things that I believe will be possible if the basic arguments I'm making at this site can be demonstrated and reduced to practice.
I believe that all of these things are possible, and that's what this part of the site is about - visions, dreams, and I hope enough facts and figures to convince a careful reader that these ideas merit discussion and consideration. And finally, I hope that you will contribute your own ideas, information, research, and suggestions. Thanks for visiting.
Many rural communities worldwide already depend on biogas for energy. A high yield source of inexpensive biogas could significantly enrich the energy environment these communities while fitting into the installed appropriate technology base.
In order to conceive of biomass tobacco you have to let go of all those images so carefully planted by the cigarette industry over the years - rows of carefully tended plants, rustic farmers and their families picking golden leaves at the peak of ripeness, aging in a rough-hewn but solid American oak barn, etc, etc.
Think of biomass tobacco as a thick, living green carpet of plants, approximately 1.5 million plants per acre according to the NCSU experiments described above. Then visualize several acres of this thick, green carpet sprouting so vigorously that every week or so the top 12" can be harvested by simple mowing, and the hundreds of thousands of stumps spring back to life immediately with new growth. These acres of rich, green young tobacco leaves, full of sugars and proteins, have the potential to end big energy as the supplier of energy needs worldwide.
Biomass tobacco is fundamentally nothing more than ordinary varieties of tobacco planted extremely close together for maximum density. Farmers with conventional tobacco growing experience will understand when I say that an ordinary tobacco seedbed is actually a small Biomass tobacco plot. Few people have never seen acres of tobacco biomass other than crop scientists at North Carolina State University, where it has been grown for over ten years for a tobacco protein extraction project .This project, run by Dr. Ray Long of the Crop Science Department of North Carolina State University, has demonstrated the practicality of biomass tobacco production for protein extraction. Dr. Long's researchers have developed and demonstrated biomass tobacco planting, irrigating, harvesting, processing and extraction techniques, and all of the costs associated with Biomass tobacco production are well-established through Ray Long's research
In addition to Dr. Long, several other scientists, primarily Dr. T.C. Tso, have been pointing out for many years that tobacco proteins have remarkable qualities and ought to be seen as food resources for both animals and humans. None of these scientists, as far as I know, did the calculations which we'll cover in this part of the site, which seem to say that if you set up even small-scale systems to extract both energy and animal protein production from biomass tobacco, then it looks feasible to wind up with low/no cost energy and low/no cost high quality protein.
What makes tobacco such a high-production biomass resource is its ability to vigorously regenerate when it is cut, a behavior called coppicing. It is this characteristic which makes possible the enormous yields per acre which have been achieved since the mid-1980's in North Carolina and in the 1920's in New Mexico, and which promise yields well in excess of 300 Tons/Acre in more favorable growing regions. Coppicing makes possible multiple mowings of a biomass tobacco field throughout a long growing season, with each mowing of the biomass field yielding many tons of high sugar, high protein, high energy young tobacco leaves and stems.
When tobacco is planted for conventional purposes it is planted in carefully spaced rows, and each plant is virtually hand-tended. Under these conditions there is no display of coppicing behavior, because the plant is never cut back. Tobacco plants have their secondary growth removed, and their flowering tops when they begin to spike, but there is never the equivalent of the mowing techniques discovered by the NCSU scientists in their protein production experiments. When tobacco is planted for biomass it is planted so close together that individual plants virtually disappear and the entire field looks like a dense green mat. When this mat is mowed using sidebar mowers, the effect created is that of a level green table. Within days this flat green surface has become a dense tangle of new shoots and leaves of the young tobacco plants, vigorously regenerating and multiplying. These young green shoots are, coincidentally, the most sugar-rich and highest protein stage of the plant's growth cycle, so the combination of tobacco's vigorous coppicing and sugar/protein production cycle coincide beautifully from the perspective of biomass food and energy production.
This coppicing behavior of biomass tobacco is shared by many other field crops, including alfalfa, and accounts for a great deal of the agricultural productivity enjoyed by growers. Coppicing behavior of plants has been studied extensively by crop scientists and others, and the factors which influence coppicing are well established. Irrigation & solar season extension systems will enable growers to control and optimize coppicing factors in biomass production, and to achieve far greater per-acre yields than have already been achieved by scientists at NCSU, and by the author in personal experiments.
The sugars in tobacco are predominantly the most easily digested types, Sucrose and Levulose. The starch is also a readily digestible or convertible carbohydrate. These sugars are prime candidates for direct conversion into ethanol, and the yield per acre achieved in the North Carolina State University tobacco biomass protein experiments leaves no doubt that biomass tobacco sugars will prove to be highly competitive with other plant sugar sources for ethanol production, but especially sugar cane, sorghum, and corn.
The implications of tobacco's sugar content are enormous for biomass energy production, since tobacco thrives in almost all inhabitable, developed regions. This means that only on the basis of its environmental range, established per-acre yield, and rich sugar profile, biomass tobacco is clearly a candidate for cost-effective production of alternative fuels. However, there's much more to this picture, as we'll see.
Tobacco's high sugar content is perhaps the primary reason that conventional producers have to use so much pesticide on their crops, because clearly in an insect world where competition for food is harsh the attraction of sweet, succulent, protein-rich young tobacco leaves is irresistable. In the case of biomass tobacco production Dr. Long's research team on the Protein Project have found that there is no need to use pesticides - the rate of growth of the biomass tobacco effectively compensates for insect predation, and the output of the production cycle isn't materially affected.
The only one of these plants which can yield anything like biomass tobacco's sugar yield per acre is sugar cane, and tobacco can grow in a much wider range of environments, and for many other reasons which we'll cover is superior to sugar cane as a source for sugars for ethanol . However, biomass sugars are only one side of the energy potential of this remarkable plant.
Energy production using tobacco biomass would produce virtually unlimited amounts of contaminant-free human food grade protein as a primary co-product. Maybe such protein is not a practical addition to upscale U.S. diets because of the association with tobacco, but it is in fact an allergen-free, complete and balanced protein, which is actually 1/3 pharmaceutical-grade, and would be produced in such enormous "paid-for" quantities as a co-product of low cost energy production that it may provide a practical and cost-effective approach to helping huge, remote populations bridge famine and starvation and recover their stability as families and communities.
The proteins in tobacco are highly unusual in the plant kingdom in that they are complete and well-balanced in their amino acid content, with all 21 amino acids that it takes to make a nutritionally complete protein, and these amino acids are in an ideal balance very similar to animal protein but, of course, without animal fat. This means that biomass tobacco can easily be a superior protein source for animal feed, with a higher Protein Efficiency Rating than either milk or soy.
We know from the agricultural literature that animals in the South are routinely fed on tobacco stalks and stems from the field after smoking tobacco crops are harvested, and these informal practices, plus USDA field trials, have shown even tobacco waste to be an excellent, well accepted forage material.
Tobacco protein is one of the potentially most valuable components of biomass production. It can be crystallized into a pure, colorless powder which has no taste or odor, and which has extremely high nutritive value with no undesirable side-effects or contaminants. A major proposed use for tobacco protein is for kidney dialysis patients who are on severely restricted diets. Most ordinary protein supplements contain excessive amounts of sodium and potassium, which must be removed before they are useful in such restricted diets. tobacco protein is very low in such contaminants, and what little is there is easily and cost-effectively removed during processing.
Tobacco protein consists of two major components- Fraction One (10%) and Fraction Two(90%). Fraction One protein is the component most valuable for medical & pharmaceutical applications, and is conservatively valued at $2.00/Lb, or half the (2006) market value of dried egg whites, its nearest competitor in Protein Efficiency Ratings. If trials were to prove its application in kidney dialysis, it would command a price of around $40/Lb (2006). Fraction Two is not pure or high value enough for medical applications, but is still higher in food value than either soy or milk, making it a potentially valuable co-product at $.45/Lb.
Other potentially valuable constituents of tobacco biomass include carotene and xanthophyll, which are in demand wherever poultry markets thrive. These two constituents are used in poultry feeding, and currently command high prices. For example, in 2005 carotene retailed to large poultry feeders at approximately $.50/Gram, or nearly $226/Lb.
The technology to extract tobacco proteins has been developed and tested by several commercial companies and research institutions. These efforts to produce commercial-grade tobacco protein have encountered bottom-line problems, in that the costs of production of protein has not yet declined sufficiently to allow a profitable operation.
However, these efforts have always been conducted in an isolated, linear applications environment, rather than as a part of an integrated system. In an integrated system, cost efficiencies developed in one set of system operations are characteristically shared by all components of the system.
Thus, the cost of producing tobacco biomass is high when that biomass is used only for protein extraction purposes, but when the biomass production costs are shared by protein extraction, energy production, soil conditioning materials, and livestock/poultry feed production, the allocated costs of biomass production for each system component is reduced significantly- enough to allow cost-effectiveness and thus profitability.
Similarly, when the waste heat of energy production is used to provide process heat for other elements of the system, costs of production for all components are lowered by what would be a wasted output in an isolated, energy-only system. The concept of integrated farming is similar in all respects to integrated planning of any other type of business which requires multiple inputs for the production of multiple outputs, in that the greater the internal integrity of all system operations, the more efficient and cost-effective the results obtained.
The cellulose in tobacco is unusual because it has very little lignin- a fact that is critical to the high-yield production of energy fuels with tobacco biomass. Lignin has been described using a construction industry metaphor as the concrete in a building encasing the steel, which is the cellulose. In order to get at the cellulose, you have to dissolve the lignin, which is as difficult on a micro level as dissolving the concrete to get at the steel would be on a macro level. So high lignin content is the primary obstacle to use of plant cellulose for conversion to fuel, and to the utilization of digester sludge as a soil conditioning material, and is the primary reason why most animals can extract so little feed value from cellulose.
But because of the almost complete absence of lignin in biomass tobacco cellulose, averaging 1.5% by dry weight, it should be an extremely cost-effective fuel resource compared with other biomass cellulose sources, and because it is very digestible it adds to the already high food values of tobacco biomass. We don't really know because nobody yet has grown biomass tobacco and fed the fresh tops to potential energy resource animals like cattle, sheep, goats, pigs or chickens. We do know that USDA and universities around the South have conducted numerous animal feeding trials beginning in the 1930's involving the successful use of both ensilaged and fresh tobacco stalks to feed animals, but these have been stalks from conventional tobacco production and there has been no evidence of any thought given to actually producing tobacco directly as animal feed, bypassing the usual uses of the biomass entirely.
While there is wide variation among tobacco types, it is possible to draw a general profile of the fermentable constituents of tobacco. This profile indicates the potential which biomass tobacco has for cost-effective conversion to ethanol fuel.
On a dry weight basis at maturity, tobacco's major components are:
In the North Carolina State University protein trials, harvested and dried biomass tobacco normally yields 20% dry weight equivalent of its green weight. This means that for a 100 metric ton (220,000 lb) biomass tobacco harvest, the dry weight yield would be roughly 20 metric tons of potentially fermentable material.
So out of a 100 MT harvest we would get approximately 5 metric tons of sugar and 2.4 metric tons of starch, both of which are directly fermentable to produce ethanol, plus 8 metric tons of cellulose, of which 7.2 tons is highly digestible holocellulose, and 0.8 tons is indigestible hemicellulose.
To calculate energy output from this 100 Metric Ton harvest
(Lbs sugar) X (.47) X (.97) divided by 6.6 = gallons ethanol
Plugging in the numbers we have established for sugar, we find:
(11,000) X (.47) X (.97) / 6.6= 760 gallons ethanol from the sugars
The conventional standard for starch-to-ethanol conversion is:
(Lbs Starch) X (.90) X (1.11) X (.47) X (.97) / 6.6= Gallons
Plugging in the starch numbers we find:
(5290)X(.90)X(1.11)X.47)X.97) / 6.6= 365 gallons ethanol from the starches
So from our hypothetical 100MT biomass harvest we get over 1000 gallons of ethanol fuel. The per-acre direct and indirect cost of producing tobacco biomass has been carefully calculated by Dr. Ray Long and his NCSU researchers for their tobacco protein project, and it falls just under $2000/acre. At this production level, the ethanol would cost $2/gallon - not very good.
However, NCSU researchers routinely achieve 120-150 Metric ton/acre production levels in a mid-length growing season environment. Dr. Long and I have worked together to estimate production in areas with longer growing seasons at between 250-400 metric tons/acre. So at 300MT/acre, which is a reasonable projection, and based on conversion of just the sugars and starches, our ethanol would cost $0.75.
Now we have to add in the ethanol we'll produce from the almost lignin-free tobacco cellulose, which will boost our ethanol production by @ 350 gallons for every 100MT of biomass we produce on an acre. At 300MT/acre production this will add over 1000 gallons to our existing sugar/starch production of roughly 3000 gallons, bringing the cost of the ethanol we produce to approximately $0.50/gallon. At this price ethanol is extremely competitive with oil.
However, it's important to realize that while we can almost certainly produce 4000 gallons of ethanol from 300MT of tobacco biomass produced on a single acre, we are also producing a number of other profit-center materials at the same time, and these materials remain available for exploitation after the ethanol has been produced. These materials, including proteins and other commercially valuable materials, add almost nothing to total costs of production, and result in income streams which effectively offset the costs of ethanol production to zero.
In other words, we're looking at a renewable source of environmentally sound, low/zero cost energy.
The story gets better.
While the economics of producing ethanol from tobacco biomass are attractive, they are not as attractive as using the tobacco biomass to feed animals, then using their manure to produce low/zero-cost, pipeline quality natural gas for low/zero-cost electric power. The reason we can say low/zero cost energy is that the animal protein production pays for 100% of the costs of biomass production, animal production, and energy production.
Here's how it would work.
Using conventional metrics for biogas production, animal manure from a herd fed on biomass tobacco would produce a minimum of 2.5 cubic feet of biogas per pound of manure. This biogas would be at least 65% methane, with an energy content of 650 Btu's per cubic Foot. I believe that the manure of animals fed on tobacco biomass would produce far more methane than this standard figure because it's based on an average of feedlot and ranged animals, and because of the rich protein/sugar content of the tobacco. However, even at the standard methane generation figures tobacco biomass feed generates some very interesting figures.
An easy way to visualize manure production - if, of course, you care to - is in terms of amounts produced per 1000 pounds of live animal weight. Animals differ for many reasons in their manure production per day, and therefore some make better candidates for straightforward energy production than others.
| Daily Manure Production Per 1000 lbs Live Animal | Daily Methane Production Per 1000 lbs Live Animal | |||
| Volume (CuFt) | Wet Weight (lbs) | Volume (CuFt) | Energy (Btu's) | |
| Sheep | 0.70 | 40.0 | 100 | 65,000 |
| Poultry | 1.00 | 62.5 | 156 | 101,562 |
| Dairy Cattle | 1.33 | 76.9 | 192 | 124,963 |
| Pigs | 1.00 | 56.7 | 142 | 92,137 |
| Feedlot Beef | 1.33 | 83.3 | 208 | 135,363 |
Let's say that the basic herd of 1500 animals, which I am using throughout these projections, will produce approximately 10 pounds of fresh manure per animal, per day, or approximately 15,000 Pounds per day. As you can see, this projection is very conservative, as are all of the figures I am using in this proposal.
At a yield of 1625 Btu per Pound, this manure production, when fully digested anaerobically, will yield the energy equivalent of 24,375,000 Btu per day.
Conventional bioenergy literature indicates that 1,707,500 Btu are required to produce a daily yield of 100 KwH electricity, which means that the daily manure output of the basic 1500 animal herd will be 1427 KwH when converted into electricity through combustion, steam generation, and conversion into electricity using conservative energy loss and efficiencies figures.
Working out to slightly less than 1 KwH per animal per day, the manure output of such a herd would be more than sufficient to supply a steam-powered generator with enough energy to produce 50 KwH every hour, 24 hours a day. At a value of $.10/KwH, this represents a value of $142.70 per day in electricity production, or approximately $52,000 per year.
Other assumptions made in arriving at the electric energy output of such a system are:(1) the biogas will be used to fuel an engine generator with an engine thermal efficiency of 25%, and a generator electrical-mechanical efficiency of 80%, and ;(2) 50% of the fuel energy is transferred to the cooling water.
Now here's where the production to tobacco biomass begins to pay off directly for the animal producer. If the farmer were buying just 5 tons of feed per day for his 1500 animals, at an average rate of between $100 and $300 per ton for animal feed, he would be paying $500 to $1500 per day, or $182,500 to $547,500 per year for animal feed.
At that rate just for feed it's easy to see why farmers and ranchers are squeezed by costs. It's also easy to see why beef producers prefer to range their beef cattle, taking advantage of whatever grass and other free forage nature provides, and then fatten them up in a few weeks at the feedlot, rather than having to feed them throughout their lives like Dairy farmers do.
First, imagine what it would do to those dairy producers' bottom lines if instead of having to pay $100-$300/ton for feed they could produce their own feed for $5 a ton or buy it from a neighbor for $10 a ton. Instead of feed costs in hundreds of thousands, their costs are now in the low thousands.
Next imagine what this would do to the bottom line and operational options of the beef rancher. With high quality feed available at $5 a ton it suddenly becomes more expensive to range your animals and to have to spend all that money rounding them up and then taking them to a feedlot than it does to simply restrict them to a limited range of a few acres, feed them in place with biomass materials at $5 a ton, then harvest their protein without additional feedlot costs.
If you are a sheep or goat rancher you have another set of economics affected by the potential of biomass tobacco. Since your production is oriented toward both fiber and meat production your output is affected by feed costs and quality in two areas - amount and quality. Most animal fiber producers range their animals simply because penned feeding at $100-$300/ton is too expensive in return for the prices brought by premium fiber produced by penned feeding. Ranged animals produce commodity-grade fiber because their diet is protein-deficient, and their environment is full of dirt and debris. Their meat grade is mutton for the same reasons.
Imagine the difference if fiber producers could pen feed their animals on high quality feed they produce themselves at $5 a ton - the difference in the quality of the fiber, the prices they would receive, their cost structure, their decreased environmental impact on rangelands, the increased quality of life for the animals, and the ranchers' production options.
These are just a few examples of how the availability of biomass tobacco as an animal feed could revolutionize animal production, increasing quality and profits and reducing costs, without even beginning to take into account the energy potential of the manure output of these penned and presumably happier creatures.
Much of the projected profitability of the proposed integrated energy system derives from the sale or utilization of digester sludge as soil improvement material. While no tests have yet been done on manure from animals fed tobacco biomass, nor has tobacco biomass itself yet been evaluated as direct charging material for anaerobic digestion, a great deal is known about the characteristics of normal digester sludge as a soil treatment.
As a rule of thumb, it is usually assumed that 70% of the organic constituents which are digestible will be decomposed under normal anaerobic conditions. The 30% or so which remains after digestion is composed of three main parts:
Practically the only materials lost from the original materials during digestion are the gasses- methane, carbon dioxide, and hydrogen sulfide. The nitrogen pathway during decomposition is particularly relevant to the use of sludge as soil treatment materials, because the amount of available nitrogen in digester sludge is typically higher after digestion than before.
The higher the nitrogen content of the materials introduced into the Digester as charging media, the higher the nitrogen content of the sludge will be. While no tests have yet been run on the N content of manure from animals fed exclusively on biomass tobacco, it is reasonable to assume that the nitrogen remaining in digested sludge from such animal manure would meet or exceed the levels in ordinary manures and plants materials.
This would mean that approximately 20% of the nitrogen in the biomass manure sludge would be in the form of ammoniacal nitrogen, and the balance in organic nitrogen.
Another major advantage of anaerobically digested materials as soil builders is that during digestion, practically all of the available trace elements are effectively chelated, or converted to a state in which they are readily available to plants when the material is plowed into the soil. This chelation of trace elements will probably prove to be extremely important with biomass tobacco as a digester charging medium, because of the abundance of trace elements taken from the soil by tobacco, and the importance of returning these elements to that soil in usable form for the next planting cycle.
One of the major differences between anaerobically digested sludge and the material produced by aerobic digestion, such as a compost pile, is that in anaerobic digestion only a relatively small amount of the available carbon and nitrogen are converted to bacterial cell mass protein. This means that anaerobically digested sludge is far less likely to smell badly or to attract insects than conventionally composted materials. In addition, during anaerobic digestion almost all weed seeds or spores are destroyed, and pathogens are either destroyed or greatly reduced in number. In addition, most of the organisms responsible for human health hazards in manure, such as intestinal parasites like worms, are destroyed in the anaerobic process, and the die-off of these organisms continues well after the sludge is removed from the digester.
There is simply no other treatment available for treatment of manure or human excrement, whether for disposal or for return to the land, that will reduce the burden of pathogenic organisms as much as does anaerobic digestion. Biomass digester sludge will contain large quantities of cellulose, as well as other original organic plant materials. Since the surfaces of most soils will contain abundant micro-organismic life, the organic constituents of digester sludge will be readily decomposed, yielding abundant humus compounds as well as H2O and CO2. This in turn will improve soil properties such as aeration, moisture-holding capacity, water infiltration capacity, and cation-exchange rates.
The size of digester required to handle a daily load of 15,000 Lbs of manure, plus water to create a slurry, and to retail its charge for 50 days in order to obtain complete digestion and Methane generation, can be calculated as follows:
Biogas technical literature offers numerous proven methods of improving biogas yield from manure and other organic materials. One of the most effective methods is simply to bubble a portion of the daily yield of biogas back through the digester, thereby agitating the slurry. This technique alone has been shown to double the daily gas output of a given amount of manure. Another simple but effective approach is to mix animal urine with the manure, using the urine to provide some or all of the moisture required to make the slurry. This approach has been shown to increase biogas yield by as much as 65% over the use of plain water.
Other simple, effective techniques include the addition of high sugar agricultural wastes to the manure slurry, or the addition of 1% actual cane sugar by weight. Either of these approaches would be cheap and simple if the energy crop being used were biomass tobacco or alfalfa, both of which are high in natural sugars.
One potential concern regarding use of biomass tobacco as a digester charging medium, or as feed for animals whose manure is used, is that tobacco takes up relatively large concentrations of certain heavy metals during its life cycle, and there is the possibility that sludge created from such material would be toxic to plants or soil microorganisms. However, a number of exhaustive studies on anaerobically digested municipal waste, with high concentrations of heavy metal contamination from human feces and industrial processes, has shown that even heavy applications of such waste to agricultural lands has not resulted in any such toxic buildup.
The principal output of either anaerobic digestion of manure, direct digestion of biomass, or fermentation of either biomass or manure to yield ethanol will be high grade gas and/or liquid fuel. This fuel will find a number of on-farm uses, including vehicle fuel, fuel for pumps etc, fuel for powering refrigeration units for meat processing etc, and process heat fuel. The CO2 output of either anaerobic digestion or ethanol fermentation will find a major usage in soil fumigation and plant growth enhancement through application via subsurface systems.
Animals fed on biomass or on its byproducts will in turn produce economic yields in terms of new animal production, including gains in existing animal live weight, output of eggs, milk, hides, animal fiber such as wool or mohair, production of fish, crayfish, shrimp, or other aquaculture products, and other site and plan-specific animal products.
A digester facility would generate natural, organic fertilizer worth approximately $30/Ton at the master distributor wholesale level, meaning an income potential of $54,000 per year per herd of 1500 animals. There is an almost unlimited market for high quality land treatment materials in many parts of the US, particularly if these materials are available at low cost to farmers and ranchers.
On the other hand, this sludge will also have considerable economic value for processing to obtain a wide range of materials with industrial applications, such as pigments, resins, free lignin, etc; an equally wide range of materials with agricultural value such as protein supplement feedstock for animals, colored poultry feed supplements, and fertilizer components; and a number of high-value applications in areas of pharmaceuticals & medical products, as well as human food-grade protein production.
All of the above applications will require more processing than simple use of the sludge as a soil-conditioning agent, but in a large farming operation, or one which operates on contract to a large processing operation off-farm, the richness and diversity of components of the biomass sludge creates a promising economic picture.
Ensilaged and pelletized tobacco biomass may provide poultry producers with the best, lowest cost feed they have ever used, and could be a factor in bringing ultra-low cost poultry protein production to even the least economically-developed areas of the world.
Egg production is an excellent method of conversion of plant feed to animal protein, with laying chickens requiring about 500 Btu's in plant protein energy to produce 25 Btu's of animal protein in the form of eggs. The plant protein is the result of twin energy inputs- solar energy and fuel energy, mostly fossil fuel energy in conventional farming. In addition to feed energy, with its solar and fossil fuel components, laying chickens require an input of their own energy to maintain their environment.
In fossil energy terms, laying chickens require 500 + 330 additional Btu's of fossil energy to produce 25 Btu's of animal protein. Clearly, anyone who can provide his own energy in replacement of fossil fuel costs in production of animal feed, either with methane for heat, electricity, and stationary engine operations, or with ethanol for vehicle fuel, and can also replace fossil fuel costs in the direct production of animal protein, in applications such as heating/cooling and lighting, will be able to produce egg protein very efficiently.
This doesn't mean that the market system is ready to absorb all this protein, so the individual farmer at one time or another may just have to feed eggs to the fish, and to the pigs, and send some to free food distribution centers in the cities. But with an integrated farm operating on principles of balance, if there is no market for eggs, use the eggs to feed other animals, and for other internal purposes until a market opens up for your eggs. If you feed eggs to the fish because there's no market for eggs, and then there's no market for your fish- sell what you can, feed some of the fish to your animals, give some away, make a few worm beds with some, and then plow the rest back into your land.
An important objection which many people raise upon first hearing of the idea of feeding biomass tobacco to animals is the fear that nicotine on the tobacco will poison or harm livestock in some way. Biomass tobacco is harvested when it is very young, well before significant concentrations of nicotine form. Also, many varieties are low nicotine, high carbohydrate plants well suited to biomass production. Finally there is plenty of evidence that small amounts of nicotine do no harm to cattle and pigs, nor probably to any other animals or creatures including man. This would not be the first instance of a potent natural toxin having little effect when consumed in small amounts. In fact, in a penned feeding situation where manure collection is the objective, a certain amount of mild nicotine addiction on the part of the animals is probably good, in that it will tend to keep them hanging around the feeding areas and the manure collection area.
One of the most important is that there is an inverse relationship between the richness of the soil and the production of carbohydrates by tobacco. In other words, the poorer the soil, the richer the tobacco for animal feed and energy production purposes. This happy circumstance means that those parts of the world which are typically the poorest, where the soils are poor, can benefit from the energy and animal forage potential of Biomass tobacco acreage.
As an example, current projections call for People's Republic of China to go on line with several hundred electric power plants in the next 20 years, most of them fueled by cheap, highly polluting soft brown coal from Western China. If PRC were to explore the tobacco biomass energy option successfully, in addition to providing its people with a new source of clean energy, it could provide employment for millions in producing the biomass for that energy, and could feed hundreds of millions of people with the animal protein produced as a sidestream to the energy being produced to power economic growth.
As another example, Turkey is a vital, high energy culture and economy with almost no energy reserves, and is therefore dependent upon uncertain relationships in a shifting world. However, Turkey also has one of the world's greatest breadbasket regions, and by my informal calculations could become energy self-sufficient by devoting approximately 3% of its current agricultural acreage to biomass tobacco energy crop production - a plant that already flourishes in Turkey in conventional forms.
My own curiosity about tobacco as a source of food and energy came about because of a combination of personal inquiries and activities around Native American tobaccos and New Mexico, where I was living in the early 1980's and this research and thinking got started.
I have many people to thank for what I've learned about tobacco over the years, but for what I know about tobacco biomass there is really only one person in the world - Dr. Ray Long, whose work on tobacco protein and whose efforts to grow tobacco biomass for the extraction of that protein led me to ask, after doing some calculating from what I was seeing in the tobacco research literature - what's happening with all that cellulose and sugar? That led to some long telephone conversations between Ray and me, and several visits since the early 1980's when this inquiry began.
For the only actual ethanol production runs so far I have to thank the folks at Floyd (Virginia) Agricultural Energy Cooperative, who so far have been the only group besides Dr. Long's NCSU team to take the idea of tobacco-based energy seriously. In 1983-84 the Floyd Coop ran a series of trials, using tobacco biomass materials from NCSU as well as conventional local tobacco scraps, which demonstrated that there is no inhibition to conventional ethanol processes and that there is a high rate of conversion of both sugars and cellulosic materials. While crunched due to economic forces generated by the federal government and especially the anti-alternative fuels DOE of the Reagan administration, the Floyd Coop experiments demonstrate that not only does tobacco not mess up ethanol production, it produces at the high conversion rates predicted.
To my knowledge nobody has yet produced a patch of biomass tobacco and fed it, before or after ensilaging it, to animals. I personally grew several plots of Native American tobacco measuring about 1/4 acre each in New Mexico in the early 1980's, and while this wasn't planted as biomass I can testify that it was extremely popular with the local animals and, of course, the insects. These patches of N. Rustica, the sacred tobacco of the Native Americans, were planted as part of the work founding a small company originally intended to work with Native American communities producing small amounts of sacred natural tobacco for sale to those who understood and cared about the difference. My interest in biomass tobacco came after I found myself without a company after some legal manuverings by some unwisely-chosen investors.
While growing this N. Rustica I thought it was interesting that this extremely high nicotine Native American tobacco didn't keep off the bugs, so I made a strong tincture of the gummiest leaves and tried spraying bugs all around the garden - on my veggies, etc. This tincture killed a few of those hardy New Mexico bugs, and staggered some others, but it left most of them unfazed.
Then, in a spirit of equality, I made a tincture using ten cigarettes in a quart of water. Voila! Dead bugs everywhere I sprayed. Just a small illustration of an interesting somewhat larger question and issue - if nicotine is such a deadly poison, why does the tobacco industry have to use all those pesticides to keep bugs from eating the plants? As you may be beginning to see, wherever you poke a stick at this subject some kind of interesting idea reveals itself.
The rest of this part of the site is devoted to an exploration of ideas, questions, possibilities, and a few probably unjustified but irresistible conclusions, usually in the form of "What if...?"
What if tobacco biomass permits the small-scale production of very clean high quality ethanol fuel at a true cost of +/- $0.50/gallon?
What if tobacco biomass means that farmers can supply the US energy needs 100% at competitive prices?
What if it turns out that the byproducts extracted from the discharge from ethanol production are themselves so valuable and easily marketed that the ethanol can be considered paid-for?
What if tobacco biomass permits small scale production of pipeline quality methane gas used to produce electricity at a fully capitalized cost of less than $0.05 per KwH?
What if tobacco biomass can be used to feed animals like goats so cost-effectively that it becomes economically feasible to give them limited range in certain kinds of terrain and to collect their droppings mechanically for energy conversion?
What if biomass tobacco energy production discharge can be used as a high quality, environmentally sound soil reclamation additive?
What if tobacco fraction 1 protein offers a cheap, high quality medical resource for millions of people?
What if it were possible for millions of small farms worldwide to supply 100% of the energy needs of the cities, and to produce 100% of a stable, moderate farm income from energy sales, which would take perhaps 50% of their time and resources leaving the rest free for diversified food production and quality of life?
What if it is possible for a village of 500 people to supply 100% of moderate food and energy needs, and to generate capital, by raising about approximately 20 acres of biomass tobacco, using it to maintain a herd of 1500 goats, and using appropriate technology to produce energy, goat meat, milk, hides, and kids?
(Adapted from Pimental et al)
The concept of integrated agriculture goes back many centuries, and examples of the practice are found in many parts of the world. The ancient Indian cultures of Mexico and central America practiced a form of integrated agriculture known as the "chinampa" system. In this form of agriculture, illustrated beautifully in several areas of the Valley of Mexico and in the Yucatan Peninsula, artificial islands, or floating gardens, were built up in shallow parts of natural lakes by piling layers of silt and aquatic plants until the surface of the island was slightly above the water level of the lake.
The islands were built in narrow strips, in order to allow continuous infiltration of fresh water. Seedlings of various crops were started in beds of organic waste and channel mud located on nearby dry land, and were transplanted onto the islands as soon as they sprouted.
As the plants grew, their "floating" beds were enriched with human and animal organic wastes and with waste from other sources, notably weeds pulled from nearby dryland fields being cleared for cultivation. Fish from the lake channels were consumed as human food, and the waste products of this consumption were returned to the soil of the "islands".
Silt from the lake bottom was continuously used to replace soil lost from the surfaces of the islands. Residues from the harvested crops were also returned to the surface of the growing beds. Cane produced on the islands was burned as a heat source, and the resulting ashes were used to enrich land on the borders of the lake used as prime agricultural territory. In this fashion, a continuous relatively closed cycle of water, soil, and organic materials were integrated with the natural energy of the sun to provide a continuously renewing energy-food cycle which supported an extremely dense population with all of the nutrients required for the development of a complex civilization.
A contemporary version of integrated farming is found in Panthum Thani province, Thailand, where a large Rice producer produces about 450 tons of Rice per day, obtaining its Rice from contract growers in the area. The by-products and co-products of rice processing are used in a closed system with multiple outputs. The Rice husks are burned to produce the energy required for parboiling, drying, and oil extraction of the Rice.
Part of the partially incinerated ash from these burned husks is used to mix with clay for a brick-making operation, and part is burned further to fire the brick-making kilns. The completely burned ash from the kiln fires is almost pure silica, and is sold for use in abrasives manufacturing. Waste heat in the flue gasses from the kiln is used for drying.
About 6000 chickens, 6000 pigs, and 7000 ducks are produced in an integrated animal production operation. About 1.4 million chicken eggs and 1.6 million duck eggs are produced and sold each year. The chicken coops are located above the feed bins for the pigs, so that wasted food and chicken droppings are consumed by the pigs. Rice crop wastes are also consumed by the pigs. Some of the pig manure is used to charge a biogas unit which generates heat for cooking that portion of the pig output which is sold as processed meat; the remainder is used to fertilize fish ponds where carp and other cash fish are raised.
The approximately 40 acres of fish and duck ponds produce 24 tons of marketable fish annually, and fish pond sludge is combined with Biogas generator sludge to produce marketable fertilizer. In addition to these major crops, significant amounts of maize, bananas, pineapples, and other food crops are produced and sold.
In the Philippines, a 60 acre integrated farm maintains approximately 15,000 pigs, and markets approximately 30,000 animals annually. Every day the 7.5 tons of manure generated by these pigs is fed into three 500 Cubic Meter Biogas Digesters which are operated on a continuous flow basis with a retention time of 25 days. The 400 Cubic Meters of gas generated daily is stored in a number of floating chamber tanks, and is used for powering deep well pumps, slurry pumps, a feed mill, and the refrigerating units of the on-farm meat packing plant.
At night, surplus gas is diverted to electricity production. The liquid effluent from the digesters is shunted into fish ponds, where it promotes heavy algae growth which in turn is prime feed for the carp population. Digester sludge is also used as 10% of the feed for the pigs, reducing costs and actually promoting faster growth.
Besides animal protein, one of the major outputs from any animal herd is manure, and with biomass ag/energy farming, manure is elevated to position of primary output. In a few feedlots across the country, and on many individual farms, manure is already being converted into methane gas by anaerobic digestion. The animals are being fed because of their production of animal protein, not because of their manure. Even though many farms replace expensive gas energy with on-site biogas, most such operations view the manure and the gas as a byproduct, rather than as a primary engine with which to drive the farm. This is because the cost of all conventional feed is too high for penned feeding of animals exclusively to produce methane energy, and of course you just don't collect the droppings of ranged animals.
Integrated energy agriculture is in concept a system in which every process feeds on the output of another process and in turn provides the energy or materials for other processes. In an ideal, well-functioning integrated system there is little or no waste, and each process feeds other processes in a loop that keeps on functioning as long as the proper balance of inputs is provided.
So in practice an integrated energy farm would consist of a series of processes, each one feeding off previous processes and then providing input for subsequent processes, with one or more energy streams - electricity, methane gas, or ethanol - as the primary outputs. In an ideal process the cost of the inputs to the system would be so low that the cost of the outputs would be competitive.
An integrated farm system begins with inputs of land, sunshine, water, labor, materials including chemicals, fuel, equipment, and other materials, and capital. In the initial cycle of operations, most or all of the materials components have to be imported into the system- specifically the irrigation and solar systems, the anaerobic digesters that break down and literally digest the plant materials, the biogas storage tanks, ethanol distillation units and storage, electricity generators, associated equipment and materials such as pipe, wiring etc, fuel, chemicals, and seed stock.
Once the system is operational, many consumable materials such as fuel and seed stock will be produced within the system, and thus these do not represent on-going imported costs of operation.
Once the farm is up and running and the right kinds of biomass material are produced and harvested, this biomass can either be used directly as charging material for anaerobic digester/ethanol distillation units, or can be utilized as livestock, poultry, or fish feed. The latter represents the most economic use of high quality biomass materials, since passing the materials through animals extracts considerable economic value from the biomass without degrading its subsequent usefulness as a charging material for anaerobic digestion or ethanol production. In other words, if you can feed biomass to animals and still extract as much or more energy from their manure as you could have from the original biomass, then you have all that animal protein as a bonus.
Existing technical and scientific literature offers plenty of guidance for anyone who wants to begin to calculate the energy balances of an integrated energy agriculture model. That doesn't make the task of constructing the model any simpler, nor does it offer any easy answers to questions about how to value different kinds of inputs and outputs, including items with confusing energy balance equations involving factors like money, and time, and other factors like environmental impact calculations.
The basic equations in farming are pretty well established. Agricultural scientists and working farmers all know pretty how many pounds of hay you need to feed a cow to produce a pound of beef, and they know that if you feed that same cow whole grains and a high protein diet, she will gain weight faster than if she grazes.
In other words, it is well established how many pounds of plant material a cow has to eat to make a pound of protein. We also know how many pounds of feed it takes to produce a dozen eggs, a pound of pork, a gallon of milk, a pound of mohair, a unit of work, and all the other products of animal consumption of plants which we grow or provide for them.
We also know how much of the solar energy which reaches the plant gets converted into the sugars, protein, starch, cellulose, and other plant materials which we feed to the animals. We know how much solar energy falls on each area of the world, and we can calculate how much of the available solar each plant receives by making physical calculations of the exposed leaf surfaces in each type of plant we want to study. All this has been exhaustively catalogued, calculated, and placed in standard reference and scientific literature, and it is readily available to anyone through A&M libraries, State University libraries, electronic data banks, and in other ways.
When we begin to calculate the energy input/output patterns, and their values in energy terms, we are dealing with well-established principles of science. The First Law of Thermodynamics states that energy can be transformed, but is neither created nor destroyed in the process.
A farmer puts direct forms of energy into the land to produce a crop of plants, whether he uses his own labor, or the labor of a draft animal, or a machine to produce that energy. The direct energy path from farmer to field to plant to harvested food, for instance, is a fundamentally simple set of transformations.
When the energy in sunlight is absorbed by a plant, a large amount of it is converted into biological energy allowing the plant to breathe, circulate its fluid components, and carry on cellular life. Much of the rest of the solar energy falling on a plant is converted by that plant directly into food energy, which the plant uses to build its own structure, systems, and fruiting parts. This same food energy is available to all other forms of life which feed upon the plants, directly or indirectly, and it is the basis for sustaining human life and the rest of organic life on Earth. The plant has taken starlight energy, plus energy from the earth, and from the hand of man, and has made the earth green, with every spot potentially a garden. The farmer is nearest of all people to this fundamental process, and it is the source of their universal love and respect for the earth. The Second Law of Thermodynamics states that in order to have transformation of energy from one form into another, energy must go from a concentrated form to a diluted form, and that in every transformation energy is lost into the environment, so no process is 100% efficient.
When the energy in gasoline is degraded by burning it in an engine, and that transformed energy is extracted as mechanical energy from the engine in order to propel a car, a huge proportion of the energy originally in the gasoline is lost to the environment. This loss takes many paths, from waste heat transferred to coolant water to energy absorbed by the resistance of each mechanical part of the engine. The energy running your car is only about 25% of the energy you paid for at the pump.
When wind flows past the blades of the windmill, only a portion of the energy absorbed by the sails arrives at ground level after passing through components which absorb energy in fulfilling their mechanical purposes. In electric power generation, only about 25% of the energy in the fuel which runs the engines is produced as electrical energy.
The basic elements of an integrated agricultural system depend upon a harmonious balancing of the energy flows within the system. The basic units for calculating such flows are the calorie, the Btu, and the watt.
The calorie is useful because with it we can calculate food energy, and compare it with any other kind of energy. Nutritional Calories are actually kilocalories, or 1000 "small" calories, which are the basic unit of nutritional energy value measurement. We'll be using the term KCal to designate this large calorie unit, which most of us know intimately as the calories in a fudge sundae or double deck burger.
The Btu is a familiar measure to Americans, and it has a value of approximately .252 KCal. Both Btu's and calories measure the amount of heat energy in foods, equating this measure with the food's potential for sustaining animal biological processes.
For instance, we can calculate the calories in the feed given to an animal, and the amount of weight the animal gains over time, and know the amount of feed it takes to produce a pound of animal protein. Equally, by calculating the caloric value of all the labor, fuels, chemicals and fertilizers, and other inputs to a field of grain, and by calculating the caloric values of the grain produced from the field, we can determine the relationship between inputs of different types of energy, and the output of food.
The watt is a measure of electrical energy, and is a measure of how much work a given amount of electricity will do in a given amount of time. The watt is equivalent to 14.3 KCal/minute, or 859 KCal/Hour as a measure of work done or energy expended by electricity. A Kilowatt/Hour of electric power is equivalent to the expenditure of 859,000 KCal in food energy. This useful conversion allows us to translate Kilowatts of electric power used in growing and processing a field of grain, vegetables or fruits, into KCalories of food energy ultimately produced by the field.
ANIMAL PROTEIN YIELD PER HECTARE IN THE US, WITH FEED & FOSSIL ENERGY INPUTS COMPARED WITH PROTEIN YIELD AND RESULTANT ENERGY RATIOS. (After Pimentel, et al, 1975)
| Type Of Protein | Protein Yield In Pounds | Feed Energy Input In KCALS | Fossil Energy Input In KCALS | Human Labor Input In Man/Hours | Ratio Feed Energy Input To Protein | Ratio Fossil Energy Input To Protein |
| Milk | 130 | 6,963,000 | 8,561,000 | 23 | 30.0 | 35.9 |
| EGGS | 400 | 14,406,000 | 9,560,000 | 174 | 20.0 | 13.1 |
| Broilers | 255 | 8,886,000 | 10,233,000 | 38 | 19.0 | 22.1 |
| Catfish | 112 | 5,007,000 | 7,068,000 | 55 | 25.0 | 34.6 |
| Pork | 143 | 17,021,000 | 9,212,000 | 28 | 65.0 | 35.4 |
| Feed Beef | 112 | 24,952,000 | 15,845,000 | 31 | 122.0 | 77.7 |
| Range Beef | 5 | 1,420,000 | 89,000 | 1 | 164 | 10.1 |
| Range Lamb | 0.17 | 128,000 | 9,000 | 0.2 | 188 | 16.2 |
This chart illustrates the vast differences in energy input/output which arise from different types of animal product production systems. It also shows you that, by and large, the more an animal has to move around for its food, the less usable protein it will make from a pound of its food, even though the protein it does make costs the farmer or rancher very little money in fossil fuels to produce the animal. On the other hand, penned animals produce much more protein per pound of feed input, and although they cost a lot more in terms of fossil fuel energy input, their output justifies the expense. Note that the figures above reflect only one aspect of the energy balance- feed and fossil energy in ... nutritional energy out.
Utilization of tobacco biomass material as animal feed presents many options to the farmer/rancher. The biomass may be fed directly to ruminant animals such as cattle, goats or sheep. It may be ensilaged and used as a feed for swine, or pelletized and used as a poultry feed. In turn, the poultry droppings may be partially recycled as feed for swine in particular, and may also be used as nutrient for fishponds.
The manure output of any type of animal being raised under penned or feedlot conditions will find its greatest economic use as a methane biogas resource material, as described in detail elsewhere. The manure also has a relatively rich potential for yielding ethanol, with a considerable advantage in that it is already processed into a form which is easy to slurry.
In a few feedlots across the country, and on many individual farms, manure is already being converted into Methane gas by anaerobic digestion. ( This simply means putting the manure and some water, usually urine into a closed tank where it can undergo chemical decomposition under limited-oxygen conditions, producing Methane gas as a byproduct of the breakdown of the manure.) However, in such operations the animals are being fed because of their production of animal protein, not because of their manure. Even though many farms replace expensive gas energy with on-site Biogas, most such operations view the Manure and the Gas as a byproduct, rather than as a primary engine with which to drive the farm. This is because the cost of all conventional feed is too high for penned feeding of animals exclusively to produce methane energy, and of course you just don't collect the droppings of ranged animals.
The key to economic success or failure of any integrated biomass operational concept lies in the original yield of the biomass materials. There are many examples of integrated biomass farm and industrial operations found throughout the world, most of them relying on conventional yields from conventional plant materials, with output enhanced as much as possible by optimizing the processing cycle.
The difference in the system I am proposing is that much greater than conventional yields per acre are realized for the original biomass materials, and that the original materials are a mix of the conventional (alfalfa, etc) and the novel (biomass tobacco). It is the extremely high yield per acre of biomass tobacco, coupled with its remarkable physical characteristics, which make the concept of integrated energy farming work at a level of economic return rarely realized in any previous situation.
Of course, along with biomass tobacco, it is important to consider the potential utility of other conventional forage crop plants in any integrated farm energy system.
You have to begin with hemp which, when combined with biomass tobacco production adds high quality plant fiber to the output stream of biomass acreage. Although I wrote the Cultivators Handbook of Marijuana back in the 1960s and have been a strong advocate of both legal marijuana and industrial hemp as cash crops for farmers I've never done a deep analysis - but fortunately many others have.
Alfalfa clearly deserves all the attention it gets as a high potential crop, and while alfalfa is nowhere as desirable as biomass tobacco, with tobacco's 40% holocellulose, 20% protein, 30% sugars & starches, and 1.5% Lignin, it is has a better profile than most conventional plant materials as a biomass resource.
Alfalfa tops are a well-balanced, high energy plant material, with the following basic constituents:
There are very real problems with feeding alfalfa as part of methane production, and the economics don't work out as a stand-alone ethanol resource, but as part of a biomass mix on an energy production farm alfalfa would be an important crop.
Other possible candidates include:
CORN
SOYBEAN TOPS
MATURE WHEATSTRAW
Perhaps the most important categories in the comparisons above are the absolute percentages, and the proportions of Hemicellulose and Holocellulose, and the % of Lignin in the plant material. The digestibility of any plant material, whether in an animal stomach or in an ethanol vat, is directly and primarily affected by these two factors, and the general rule is that the higher the proportion and percentage of Holocellulose, the more digestible and higher food-energy the plant material will be. Equally, the lower the percentage of