Biochar: Wikis

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Left - a nutrient-poor oxisol; right - an oxisol transformed into fertile terra preta using biochar.

Biochar is charcoal created by pyrolysis of biomass, and differs from charcoal only in the sense that its primary use is not for fuel, but for biosequestration or atmospheric carbon capture and storage.[1] Charcoal is a stable solid rich in carbon content, and thus, can be used to lock carbon in the soil. Biochar is of increasing interest because of concerns about climate change caused by emissions of carbon dioxide (CO2) and other greenhouse gases (GHG). Carbon dioxide capture also ties up large amounts of oxygen and requires energy for injection (as via carbon capture and storage), whereas the biochar process breaks into the carbon dioxide cycle, thus releasing oxygen as did coal formation hundreds of millions of years ago. Biochar is a way for carbon to be drawn from the atmosphere and is a solution to reducing the global impact of farming (and in reducing the impact from all agricultural waste). Since biochar can sequester carbon in the soil for hundreds to thousands of years[2], it has received considerable interest as a potential tool to slow global warming. The burning and natural decomposition of trees and agricultural matter contributes a large amount of CO2 released to the atmosphere. Biochar can store this carbon in the ground, potentially making a significant reduction in atmospheric GHG levels; at the same time its presence in the earth can improve water quality, increase soil fertility, raise agricultural productivity and reduce pressure on old growth forests.[3]

Current biochar projects are small scale and make no significant impact on the overall global carbon budget, although expansion of this technique has been advocated as a geoengineering approach. As trees pull down carbon dioxide and release oxygen very efficiently they are already well suited to geoengineering. Further research is in progress, notably by the University of Edinburgh, which has a dedicated research unit.[4] Agrichar is produced by Best Industries in Australia.

The approach which favors applications that benefit the poorest is gaining traction: in May 2009, the Biochar Fund received a grant from the Congo Basin Forest Fund to implement its concept in Central Africa. In this concept, biochar is a tool used to simultaneously slow down deforestation, increase the food security of rural communities, provide renewable energy to them and sequester carbon.[5]

Contents

History

Pre-Columbian Amazonian Natives are believed to have used biochar to enhance soil productivity and made it by smoldering agricultural waste[6]. European settlers called it Terra Preta de Indio.[7]. Following observations and experiments by a research team working in French Guiana it has been hypothesized that the Amazonian earthworm Pontoscolex corethrurus was the main agent of fine powdering and incorporation of charcoal debris to the mineral soil[8].

Biochar is a high-carbon, fine-grained residue which used to be produced using centuries-old techniques by smoldering biomass (i.e., covering burning biomass with soil and letting it smolder). Biochar is another word for charcoal. The ancient method for producing charcoal for native use as fuel (and accidentally as a soil additive) was the “pit” or “trench” method, which created terra preta, or dark soil after abandonment.[9]

Uses

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Carbon sink potential

Biochar can sequester carbon in the soil for hundreds to thousands of years, like coal[2]. Modern biochar is being developed using pyrolysis to heat biomass in the absence of oxygen in kilns[10]. However, to the difference of coal and/or petroleum charcoal, when incorporated to the soil in stable organo-mineral aggregates does not freely accumulate in an oxygen-free and abiotic environment. This allows it to be slowly oxygenated and transformed in physically stable but chemically reactive humus, thereby acquiring interesting chemical properties such as cation exchange capacity and buffering of soil acidification, both are precious in nutrient- and clay-poor tropical soils[11]. Modern biochar production can be combined with biofuel production in a process that may produce 3 to 9 times more energy than invested, is carbon-negative (withdraws more carbon from the atmosphere than it releases) and rebuilds geological carbon sinks[12]. This technique is advocated by prominent scientists such as James Lovelock, creator of the Gaia hypothesis, for mitigation of global warming by greenhouse gas remediation.[13]

Biochar is a high-carbon, fine-grained residue which today is produced through modern pyrolysis processes. Pyrolysis is the direct thermal decomposition of biomass in the absence of oxygen to obtain an array of solid (biochar), liquid (bio-oil) and gas (syngas) products. The specific yield from the pyrolysis is dependent on process conditions, and can be optimized to produce either energy or biochar[14]. Even when optimized to produce char rather than energy, the energy produced per unit energy input is higher than for corn ethanol[15].

Use as a carbon sink

Biochar can be used to hypothetically sequester carbon on centurial or even millennial time scales. In the natural carbon cycle, plant matter decomposes rapidly after the plant dies, which emits CO2; the overall natural cycle is carbon neutral. Instead of allowing the plant matter to decompose, pyrolysis can be used to sequester some of the carbon in a much more stable form. Biochar thus removes circulating CO2 from the atmosphere and stores it in virtually permanent soil carbon pools, making it a carbon-negative process. In places like the Rocky Mountains, where beetles have been killing off vast swathes of pine trees, the utilization of pyrolysis to char the trees instead of letting them decompose into the atmosphere would offset substantial amounts of CO2 emissions. Although some organic matter is necessary for agricultural soil to maintain its productivity, much of the agricultural waste can be turned directly into biochar, bio-oil, and syngas.[16] The use of pyrolysis also provides an opportunity for the processing of municipal waste into useful clean energy rather than increased problems with land space for storage.[17]

Biochar is believed to have long mean residence times in the soil. While the methods by which biochar mineralizes (turns into CO2) are not completely known,[18] evidence from soil samples in the Amazon shows large concentrations of black carbon (biochar) remaining after they were abandoned thousands of years ago.[19] The amount of time the biochar will remain in the soil depends on the feedstock material, how charred the material is, the surface:volume ratio of the particles, and the conditions of the soil the biochar is placed in.[20] Estimates for the residence time range from 100 to 10,000 yrs, with 5,000 being a common estimate.[21] Lab experiments confirm a decrease in carbon mineralization with increasing temperature, so carefully controlled charring of plant matter can increase the soil residence time of the biochar C.[22]

Under some circumstances, the addition of biochar to the soil has been found to accelerate the mineralization of the existing soil organic matter, probably from the excessive potash and increased pH from biochar[23] but this would only reduce and not suppress the net benefit gained by sequestering carbon in the soil by this method. Furthermore, the suggested soil conditions for the integration of biochar are in heavily degraded tropical soils used for agriculture, not organic matter-rich boreal forest soils (as tested in the above reference).

Assuming biochar is effective at storing carbon for adequately long periods of time, serious questions remain as to whether biochar will play a significant role in combatting global warming. First is a question of scale. Assuming a natural carbon cycle in which trees absorb and release 120 billion tonnes of carbon per year, and human-caused emissions of 8 billion to 10 billion tonnes per year,[24] in order to address even half of human-caused emissions, biochar would require harvesting of 3% to 4% of the world's forests per year - an enormous undertaking. Just the notion of making "nature to blame" by requiring nature's biogenic carbon to be made into biochar, an alibi for fossil carbon from industry, instead of contributing biologically to soil humus formation and microbial ecology, borders on the extreme. In fact, from this point of view, biochar from plant material deprives the soil of necessary humus and biologically active carbon. In this sense, it is most likely a significant detriment to the environment.

There is another combined question of policy and markets. Energy produced from producing biochar is less than that produced from burning biomass. Thus, in order to scale up biochar to industrial levels worldwide, there would need to be a significant price imposed on carbon emissions so as to make biochar more financially attractive than burning. Yet if there were a significant price on carbon emissions, alternative (non-biochar) techniques for carbon reduction would become increasingly cost-effective.

Johannes Lehmann, of Cornell University, estimates that pyrolysis can be cost-effective for a combination of sequestration and energy production when the cost of a CO2 ton reaches $37 [25]. As of mid-February 2010, CO2 is trading at $16.82/ton on the European Climate Exchange (the ECX), so using pyrolysis for bioenergy production may be feasible even if it is more expensive than fossil fuels.

The technology for biochar sequestration does not require a fundamental scientific advance. The underlying production technology is robust and simple, making it appropriate for many regions of the world. [26]

There is a separate question as to whether it is justifiable at all to take biogenic active carbon "out of circulation" in order to reduce other sources of atmospheric fossil CO2.

Positive and Negative Effects on Soil

Biochar may be a substance mostly suited to severely weathered and deprived soils (low pH, absent potassium, low or no humus). Clearly, there is the real potential for carbon sequestration, simply because biochar is so stable and is not accessible to normal microbial decay. Soils require active carbon to maintain micro and macro populations, not the inactive form found in biochar [27]. Biochar can prevent the leaching of nutrients out of the soil, partly because it absorbs and immobilizes certain amounts of nutrients, however, too much immobilization can be harmful [28][29]. It has been reported to increase the available nutrients for plant growth, but also depress them [30][31] increase water retention,[32] and reduce the amount of fertilizer required. Additionally, it has been shown to decrease N2O (Nitrous oxide) and CH4 (methane) emissions from soil, thus further reducing GHG emissions.[33] Although it is far from a perfect solution in all economies, biochar can be utilized in many applications as a replacement for or co-terminous strategy with other bioenergy production strategies.[34]

Co-benefits for soil of pyrolysis

Biochar can be used as a soil amendment to affect plant growth yield, but only for plants that love high potash and elevated pH [35], improve water quality, reduce soil emissions of GHGs, reduce leaching of nutrients, reduce soil acidity, and reduce irrigation and fertilizer requirements.[36].

These positive qualities are dependent on the properties of the biochar,[37] and may depend on regional conditions including soil type, condition (depleted or healthy), temperature, and humidity.[38] Modest additions of biochar to soil were found to reduce N2O emissions by up to 80% and completely suppress methane emissions.[39]

Pollutants such as metals and pesticides seep into the earth's soil and contaminate the food supply. This pollution reduces the amount of land suitable for agricultural production and contributes to global food shortages. Studies have reported positive effects to crop production in highly degraded and nutrient poor soils [40]. Biochars can be designed to have specific qualities that can target distinct properties of soils [41].Application of biochar reduces leaching of critical nutrients, creates a higher crop uptake of nutrients, while also providing greater soil availability of nutrients [42]. Biochar added at 10% levels reduced contaminant levels in plants by up to 80%, while reducing total chlordane and DDX content in the plants by 68 and 79%,[43].

Animal feed

Before incorporating biochar into the soil, it also has use as dietary supplement for animals, and traditionally as charcoal biscuits for humans. These reports are possibly dubious however, and a veterinary should be consulted before animals are exposed. The effects of this are to provide additional minerals, maintain a healthy digestive system, reduce flatulence (which is a source of methane), and reduce the odour of and ammonia emissions from slurry (ie. sweeten the dung). However raising the pH of dung causes huge ammonia-N losses, so this practice is also dubious. Caution: Use of highly alkaline and especially high potash biochar in animal grazing systems could lead directly to grass tetany, a severe and sudden ailment that is often fatal to milking cows.

Slash and char

Switching from slash-and-burn to slash-and-char techniques in Brazil can both decrease deforestation of the Amazon and increase the crop yield. Under the current method of slash-and-burn, only 3% of the carbon from the organic material is left in the soil.[44]

Switching to slash-and-char can sequester up to 50% of the carbon in a highly stable form.[45] Adding the biochar back into the soil rather than removing it all for energy production is necessary to avoid heavy increases in the cost and emissions from more required nitrogen fertilizers.[46] Additionally, by improving the soil tilth, fertility, and productivity, the biochar enhanced soils can sustain agricultural production, whereas non-amended soils quickly become depleted of nutrients, and the fields are abandoned, leading to a continuous slash-and-burn cycle and the continued loss of tropical rainforest. Using pyrolysis to produce bio-energy also has the added benefit of not requiring infrastructure changes the way processing biomass for cellulosic ethanol does. Additionally, the biochar produced can be applied by the currently used tillage machinery or equipment used to apply fertilizer.[47]

Energy production: bio-oil

Bio-oil can be used as a replacement for numerous applications where fuel oil is used, including fueling space heaters, furnaces, and boilers.[48] Additionally, these biofuels can be used to fuel some combustion turbines and reciprocating engines, and as a source to create several chemicals.[49] If bio-oil is used without modification, care must be taken to prevent emissions of black carbon and other particulates. Syngas and bio-oil can also be “upgraded” to transportation fuels like biodiesel and gasoline substitutes.[50] If biochar is used for the production of energy rather than as a soil amendment, it can be directly substituted for any application that uses coal. pyrolysis also may be the most cost-effective way of producing electrical energy from biomaterial.[51] Syngas can be burned directly, used as a fuel for gas engines and gas turbines, converted to clean diesel fuel through Fischer Tropsch or potentially used in the production of methanol and hydrogen.[52]

Bio-oil has a much higher energy density than the raw biomass material.[53] Mobile pyrolysis units can be used to lower the costs of transportation of the biomass itself if the biochar is returned to the soil and the syngas stream is used to power the process.[54][55] Bio-oil contains organic acids which are corrosive to steel containers, has a high water vapor content which is detrimental to ignition, and, unless carefully cleaned, contains some biochar particles which can block injectors.[56] The greatest potential for bio-oil seems to be its use in a bio-refinery, where compounds that are valuable chemicals, pesticides, pharmaceuticals or food additives are first extracted, and the remainder is either upgraded to fuel or reformed to syngas.[57]

Production of biochar

The yield of products from pyrolysis varies heavily with temperature. The lower the temperature, the more char is created per unit biomass.[58] High temperature pyrolysis is also known as gasification, and produces primarily syngas from the biomass.[59] The two main methods of pyrolysis are “fast” pyrolysis and “slow” pyrolysis. Fast pyrolysis yields 60% bio-oil, 20% biochar, and 20% syngas, and can be done in seconds, whereas slow pyrolysis can be optimized to produce substantially more char (~50%), but takes on the order of hours to complete. For typical inputs, the energy required to run a “fast” pyrolyzer is approximately 15% of the energy that it outputs.[60] Modern pyrolysis plants can be run entirely off of the syngas created by the pyrolysis process and thus output 3–9 times the amount of energy required to run.[61] Alternatively, microwave technology has recently been used to efficiently convert organic matter to biochar on an industrial scale, producing ~50% char.[62]

The ancient method for producing biochar as a soil additive was the “pit” or “trench” method, which created terra preta, or dark soil.[9] While this method is still a potential to produce biochar in rural areas, it does not allow the harvest of either the bio-oil or syngas, and releases a large amount of CO2, black carbon, and other GHGs (and potentially, toxins) into the air. Modern companies are producing commercial-scale systems to process agricultural waste, paper byproducts, and even municipal waste.

There are three primary methods for deploying a pyrolysis system. The first is a centralized system where all biomass in the region would be brought to a pyrolysis plant for processing. A second system would effectively mean a lower-tech pyrolysis kiln for each farmer or small group of farmers. A third system is a mobile system where a truck equipped with a pyrolyzer would be driven around to pyrolyze biomass. It would be powered using the syngas stream, return the biochar to the earth, and transport the bio-oil to a refinery or storage site. Whether a centralized system, a distributed system, or a mobile system is preferred is heavily dependent on the specific region. The cost of transportation of the liquid and solid byproducts, the amount of material to be processed in a region, and the ability to feed directly into the power grid are all factors to be considered when deciding on a specific implementation.

Unless crops are going to be dedicated to biochar production, the residue-to-product ratio (RPR) for the feedstock material is a useful gauge of the approximate amount of feedstock that can be obtained for pyrolysis after the primary product is harvested and the waste remains. The amount of crop residue available to be used for pyrolysis can be determined by using the RPR, and the collection factor (the percent of the residue not used for other things). For instance, Brazil harvests approximately 460Mt of sugar cane annually[63], with an RPR of 0.30, and a collection factor (CF) of 0.70 for the sugar cane tops, which are normally burned on the field.[64] This translates into approximately 100Mt of residue which can be pyrolyzed to create energy and soil additives annually. Adding in the bagasse (sugar cane waste) (RPR=0.29 CF=1.0) which is currently burned inefficiently in boilers, raises the total to 230 Mt of pyrolysis feedstock just from sugar cane residues. Some plant residue, however, must remain on the soil to avoid heavily increased costs and emissions from nitrogen fertilizers.[65]

Nevertheless some technologies of pyrolysis of loose and leafy biomass have been developed which produce both biochar and syngas from them [66]

Commercial viability

Current biochar projects are small scale, though many developments show that organic matter can be efficiently turned into biochar, potentially making a significant impact on the overall global carbon budget.[67][68]

Emerging commercial sector

A commercial production plant opened in Dunlap, Tennessee in August 2009 after testing and an initial run. It was subsequently shut down as part of a Ponzi scheme investigation. [69] The plant was a "pressurized partially pyrolytic gasification" system using 3.5 ton autoclave units loaded with canisters full of feedstock. The system was to operate between 400 and 800 °C to produce an estimated output of "8,000 pounds per hour".[70] The 2009 International Biochar Conference in Boulder, Colorado saw the launch of a mobile pyrolysis unit with a specified intake of 1,000 pounds per hour. The unit, with a length of 12 feet and height of 7 feet, is intended for agricultural applications.[71]

See also

References

  1. ^ Biochar Carbon Sequestration - Comment to bioenergy with carbon storage (BECS)
  2. ^ a b Terra Preta de Indio, Lehmann, Johannes, in Soil Biochemistry (internal citations omitted); see also Biochar and Bioenergy Production for Climate Change Mitigation, Winsley, Peter, 64 New Zealand Sci. Review. 5, 5 (2007); Kern, Dirse C.,New Dark Earth Experiment in the Tailandia City – Para-Brazil: The Dream of Wim Sombroek, 18th World Congress of Soil Science (9-15 July 2006). Not only do biochar-enriched soils contain more carbon, 150gC/kg compared to 20-30gC/kg in surrounding soils, but biochar-enriched soils are, on average, more than twice as deep as surrounding soils. Therefore, the total carbon stored in these soils can be one order of magnitude higher than adjacent soils. See id
  3. ^ Laird, David A., The Charcoal Vision: A Win–Win–Win Scenario for Simultaneously Producing Bioenergy, Permanently Sequestering Carbon, while Improving Soil and Water Quality, AGRONOMY J., 100 178-181 (2008)
  4. ^ "The UK Biochar Research Centre (UKBRC)". University of Edinburgh. http://www.geos.ed.ac.uk/sccs/biochar/. Retrieved 2009-03-10. 
  5. ^ Biochar project wins critical funding for protection of rainforests in Congo
  6. ^ Solomon, Dawit, Johannes Lehmann, Janice Thies, Thorsten Schafer, Biqing Liang, James Kinyangi, Eduardo Neves, James Petersen, Flavio Luizao, and Jan Skjemstad, Molecular signature and sources of biochemical recalcitrance of organic carbone in Amazonian Dark Earths, 71 Geochemica et cosmochemica ACTA 2285, 2286 (2007) (“Amazonian Dark Earths (ADE) are a unique type of soils apparently developed between 500 and 9000 years B.P. through intense anthropogenic activities such as biomass-burning and high-intensity nutrient depositions on pre-Columbian Amerindian settlements that transformed the original soils into Fimic Anthrosols throughout the Brazilian Amazon Basin.”) (internal citations omitted)
  7. ^ Glaser, Bruno, Johannes Lehmann, and Wolfgang Zech, Ameliorating physical and chemical properties of highly weathered soils in the tropics with charcoal – a review, 35 Biology and Fertility of Soils 219, 220 (2002) (“These so called Terra Preta do Indio (Terra Preta) characterize the settlements of pre-Columbian Indios. In Terra Preta soils large amounts of black C indicate a high and prolonged input of carbonized organic matter probably due to the production of charcoal in hearths, whereas only low amounts of charcoal are added to soils as a result of forest fires and slash-and-burn techniques.”) (internal citations omitted)
  8. ^ Jean-François Ponge, Stéphanie Topoliantz, Sylvain Ballof, Jean-Pierre Rossi, Patrick Lavelle, Jean-Marie Betsch and Philippe Gaucher,Ingestion of charcoal by the Amazonian earthworm Pontoscolex corethrurus: a potential for tropical soil fertility, 38 Soil Biology & Biochemistry, 2008, 2009 (2006)
  9. ^ a b To date, scientists have been unable to completely reproduce the beneficial growth properties of terra preta. It is hypothesized that part of the alleged benefits of terra preta require the biochar to be aged so that it increases the cation exchange capacity of the soil, among other possible effects. In fact, there is no evidence natives made biocahr for soil treatment, but really for transportable fuel charcoal. Abandoned or forgotten charcoal pits left for centuries were eventually reclaimed by the forest. In that time the harsh negative effects of the char (high pH, extreme ash content, salinity) had worn off and turned to positive as the forest soil ecosystem saturated the charcoals with nutrients. Lehmann, Bio-energy in the black, supra note 2 at 386 (“Only aged biochar shows high cation retention, as in Amazonian Dark Earths. At high temperatures (30–70°C), cation retention occurs within a few months. The production method that would attain high CEC in soil in cold climates is not currently known.”) (internal citations omitted).
  10. ^ Lehmann, Johannes, A handful of carbon, 447 Nature 143, 143 (2007) (“this sequestration can be taken a step further by heating the plant biomass without oxygen (a process known as low-temperature pyrolysis).”)
  11. ^ Glaser, Bruno, Johannes Lehmann, and Wolfgang Zech, Ameliorating physical and chemical properties of highly weathered soils in the tropics with charcoal – a review, 35 Biology and Fertility of Soils 219, 220 (2002)
  12. ^ Lehmann, Johannes, Bio-energy in the black, 5 Front Ecol Environ 381, 385 (2007) (“pyrolysis produces 3–9 times more energy than is invested in generating the energy. At the same time, about half of the carbon can be sequestered in soil. Such a carbon-negative technology would lead to a net withdrawal of CO2 from the atmosphere, while producing and consuming energy.”)
  13. ^ One last chance to save mankind 23 January 2009 by Gaia Vince Magazine issue 2692. New Scientist
  14. ^ Gaunt, John L. and Johannes Lehmann, Energy Balance and Emissions Associated with Biochar Sequestration and pyrolysis Bioenergy Production, 42 Environmental Sciences & Technologies. 4152, 4155 (2008) (“Assuming that the energy in syngas is converted to electricity with an efficiency of 35%, the recovery in the life cycle energy balance ranges from 92 to 274 kg CO2 MW-1 of electricity generated where the pyrolysis process is optimized for energy and 120 to 360 kg CO2 MW-1 where biochar is applied to land. This compares to emissions of 600–900 kgCO2MW-1 for fossil-fuel-based technologies.)
  15. ^ Id. at 4152 (“Despite a reduction in energy output of approximately 30% where the slow pyrolysis technology is optimized to produce biochar for land application, the energy produced per unit energy input at 2–7 MJ/MJ is greater than that of comparable technologies such as ethanol from corn.”)
  16. ^ The question scientists are debating is precisely how much can be removed. Adding the char back into the soil makes up for a large amount of the SOM (soil organic matter) needed, but it may not be sufficient in all cases.
  17. ^ Shinogi, Y., H. Yoshida, T. Koizumi, M. Yamaoka, and T. Saito, Basic characteristics of low-temperature carbon products from waste sludge, 7 Advances Envtl. RES. 661, (2003) (“The results showed there are not harmful levels (based on the Japanese standard) of heavy metals and harmful substances.”), See also Flash Carbonization, M. Antal, Hawaii Natural Energy Institute (1 July 2008).
  18. ^ Masiello, C.A., New directions in black carbon organic geochemistry, 92 Marine Chemistry 201, 202 (2004) (“We know little about black carbon (biochar) loss processes and almost nothing about biotic or abiotic agents of black carbon decomposition.”)
  19. ^ Lehmann, Johannes, John Gaunt, and Marco Rondon, Biochar Sequestration In Terrestrial Ecosystems – A Review, supra note 11 Mitigation and Adaptation Strategies for Global Change 403, 404 (2006) (“Large amounts of biochar-derived carbone stocks remain in these soils today, hundreds and thousands of years after they were abandoned. The total carbone storage is as high as 250MgCha−1 m−1 compared to typical values of 100MgCha−1 m−1 in Amazonian soils derived from similar parent material.”) (internal citations omitted).
  20. ^ Cheng, Chih-Hsin, Johannes Lehmann, and Mark H. Engelhard, Natural oxidation of black carbon in soils: Changes in molecular form and surface charge along a climosequence, 72 Geochemica et Cosmochemica ACTA 1598, 1599 (2008) (“Biotic and abiotic processes, such as greater temperature and moisture, may facilitate black carbon oxidation, while aggregate protection of black carbon [decreased surface to volume ratio] promoted in fine-textured soils may reduce black carbon oxidation.”); see also infra note 17.
  21. ^ Cheng, Chih-Hsin, Johannes Lehmann, Janice E. Thies, and Sarah D. Burton, Stability of black carbon in soils across a climatic gradient, 113 J. Geophysical Res. G02027, 8 (2008) (“the half-life of black carbon at a site with 10C MAT may be as high as 925 years. Due to systematic overestimation of long-term black carbon decay by short-term incubations, the true half-life of black carbon is most likely greater than calculated here. This agrees well with the C-14 ages of black carbon which have been reported to lie in the hundreds to thousands of years”) (emphasis added) (internal citations omitted); Warnock, Daniel D. & Johannes Lehmann, Mycorrhizal responses to biochar in soil – concepts and mechanisms, 300 Plant & Soil 9 (2007) (“Biochar is believed to have long mean residence times in soil, ranging from 1,000 to 10,000 years, with 5,000 years being a common estimate.”)
  22. ^ Baldock and Smernik (2002) used red pine (Pinus resinosa) wood charred at different temperatures. After 120 days incubation in sand, 20% of carbone was mineralized from wood heated at 70 carbone (essentially unaltered). Carbon mineralization decreased to 13% for wood heated to 150 C, and to less than 2% for chars produced at 200–350 C, with increasing proportions of aromatic C.
  23. ^ Wardle, David, Marie-Charlotte Nilsson, and Olle Zackrisson, Fire-Derived Charcoal Causes Loss of Forest Humus, 320 Science 1 (2 May 2008) (“Although several studies have recognized the potential of black C for enhancing ecosystem carbone sequestration, our results show that these effects can be partially offset by its capacity to stimulate loss of native soil C, at least for boreal forests.”) (emphasis added) (internal citations omitted).
  24. ^ http://www.newscientist.com/article/dn14851
  25. ^ Lehmann, Johannes,A handful of carbon, 447 Nature 143, 144 (2007). (“We calculate that biochar sequestration in conjunction with bioenergy from pyrolysis becomes economically attractive, under one specific scenario, when the value of avoided carbon dioxide emissions reaches $37 per tonne.”)
  26. ^ Id.
  27. ^ Soil Biology, With Special Reference to the Animal Kingdom. 2d EdIt . Kuehnelt
  28. ^ Steiner, Christoph, Wenceslau G. Teixeira, Johannes Lehmann, Thomas Nehls, Jeferson Luis, Vasconcelos de Macêdo, Winfried E. H. Blum, Wolfgang Zech, Long term effects of manure, charcoal and mineral fertilization on crop production and fertility on a highly weathered Central Amazonian upland soil, 291 Plant & Soil 275, 287 (“The application of charcoal significantly reduced leaching of applied mineral fertilizer N. The increased ratio of uptake to leaching due to charcoal application indicates a high efficiency of nutrients applied with charcoal.”)
  29. ^ Note: Biochar can also severely immobilize nutrients rendering them unavailable for immediate plant growth. Container mix trials are reported in which biochar suppressed growth more than adding raw chipped wood.
  30. ^ See previous note about severe immobilization
  31. ^ Id. (“The increased ratio of uptake to leaching due to charcoal application indicates a high efficiency of nutrients applied with charcoal. In this study, we were not able to statistically prove increased availability of soil nutrient contents but in spite of significantly higher nutrient export by means of yield withdrawal, the available nutrient contents remained as high or higher in soils receiving charcoal than only mineral fertilized soils (Fig. 4).”)
  32. ^ Glaser, Bruno, Johannes Lehmann, and Wolfgang Zech, Ameliorating physical and chemical properties of highly weathered soils in the tropics with charcoal – a review, 35 Biology and Fertility Soils 219, 223 (2002) (“[S]oil water retention increased by 18% upon addition of 45% (by volume) charcoal to a sandy soil. Glaser et al. (2002b) reported that charcoal-rich Anthrosols whose surface areas were 3 times higher than those of surrounding soils increased the field capacity by 18%. Tryon (1948) also studied the effect of charcoal on the percentage of available moisture in soils of different textures. Only in sandy soil did the addition of charcoal increase the available moisture (Table 3). In loamy soil, no changes were observed, and in clayey soil the available soil moisture even decreased with increasing coal additions, probably due to hydrophobicity of the charcoal. Therefore, improvements of soil water retention by charcoal additions may only be expected in coarse-textured soils or soils with large amounts of macropores”) (internal citations omitted) (citing Tryon, EH, Effect of charcoal on certain physical, chemical, and biological properties of forest soils, 18 Ecological Monographs 81 1948)).
  33. ^ Gaunt, supra note 3 at 4152. (“Rondon et al. found that CH4 emissions were completely suppressed and N2O emissions were reduced by 50% when biochar was applied to soil. Yanai et al. also found suppression of N20 when biochar was added to soil”) (internal citations omitted).
  34. ^ Toohey, Brian (2008-12-30). "A perfect green solution: In theory". The Weekend Australian Financial Review: p. 22. 
  35. ^ Lehmann, Johannes, and Jose Pereira da Silva Jr., Christoph Steiner, Thomas Nehls, Wolfgang Zech, & Bruno Glaser, Nutrient availability and leaching in an archaeological Anthrosol and a Ferralsol of the Central Amazon basin: fertilizer, manure and charcoal amendments, 249 Plant & Soil 343, 355 (2003)
  36. ^ Supra note 6; Day, Danny, Robert J. Evans, James W. Lee, and Don Reicosky, Economical CO2, SOx, and NOx capture from fossil-fuel utilization with combined renewable hydrogen production and large-scale carbon sequestration, 30 Energy 2558, 2560
  37. ^ Glaser, supra note 7 at 224 (“Three main factors influence the properties of charcoal: (1) the type of organic matter used for charring, (2) the charring environment (e.g. temperature, air), and (3) additions during the charring process. The source of charcoal material strongly influences the direct effects of charcoal amendments on nutrient contents and availability.”)
  38. ^ Dr. Wardle points out that plant growth has been observed in tropical (depleted) soils by referencing Lehmann, but that in the boreal (high native soil organic matter content) forest this experiment was run in, it accelerated the native soil organic matter loss. Wardle, supra note 18. (“Although several studies have recognized the potential of black C for enhancing ecosystem carbone sequestration, our results show that these effects can be partially offset by its capacity to stimulate loss of native soil C, at least for boreal forests.”) (internal citations omitted) (emphasis added).
  39. ^ Lehmann - Bioenergy in the Black, supra note 3 at 384. (“In greenhouse experiments, NOx emissions were reduced by 80% and methane emissions were completely suppressed with biochar additions of 20 g kg-1 (2%) to a forage grass stand.”)
  40. ^ http://www.csiro.au/resources/Biochar-Factsheet.html
  41. ^ Novak, Jeff. Development of Designer Biochar to Remediate Specific Chemical and Physical Aspects of Degraded Soils. Proc. of North American Biochar Conference 2009, Universtiy of Colorado at Boulder. Florence: U.S. Department of Agriculture, 2009. 1-16. Print
  42. ^ Julie, Major, Johannes Lehmann, Macro Rondon, and Susan J. Riha. Nutrient Leaching below the Rooting Zone Is Reduced by Biochar, the Hydrology of a Columbian Savanna Oxisol Is Unaffected. Proc. of North American Biochar Conference 2009, Universtiy of Colorado at Boulder. Ithaca: Cornell University Department of Crop and Soil Sciences, 2009. Print.
  43. ^ Elmer, Wade, Jason C. White, and Joseph J. Pignatello. Impact of Biochar Addion to Soil on the Bioavailability of Chemicals Important in Agriculture. Rep. New Haven: University of Conneticut, 2009. Print).
  44. ^ Glaser, supra note 7 at 225 (“The published data average at about 3% charcoal formation of the original biomass C.”)
  45. ^ Biochar Sequestration In Terrestrial Ecosystems – A Review, by Johannes Lehmann, John Gaunt, and Marco Rondon. Mitigation and Adaptation Strategies for Global change 403, 404 (2006). supra note 11 at 407 (“If this woody aboveground biomass were converted into biochar by means of simple kiln techniques and applied to soil, more than 50% of this carbone would be sequestered in a highly stable form.”)
  46. ^ Gaunt, supra note 3 at 4152 (“This results in increased crop yields in low-input agriculture and increased crop yield per unit of fertilizer applied (fertilizer efficiency) in high-input agriculture as well as reductions in off-site effects such as runoff, erosion, and gaseous losses.”)
  47. ^ Lehmann, A handful of carbon, supra note 9 at 143. (“It can be mixed with manures or fertilizers and included in no-tillage methods, without the need for additional equipment.”)
  48. ^ Badger, Phillip C. and Peter Fransham, Use of mobile fast pyrolysis plants to densify biomass and reduce biomass handling costs—A preliminary assessment, 30 Biomass & Bioenergy 321, 322 (2006) (“including fueling space heaters, furnaces, and boilers (including cofiring in utility boilers); and fueling certain combustion turbines and reciprocating engines, as well as serving as a source of several chemicals.”)
  49. ^ Id.
  50. ^ Laird, supra note 21 at 178.
  51. ^ Bridgwater, A. V., A.J. Toft, and J.G. Brammer, A techno-economic comparison of power production by biomass fast pyrolysis with gasification and combustion, 6 Renewable & Sustainable Energy Rev. 181, 231 (“the fast pyrolysis and diesel engine system is clearly the most economic of the novel systems at scales up to 15 MWe”);
  52. ^ McKendry, Peter, Energy production from biomass (part 2): conversion technologies, 83 BIORESOURCE TECH. 47, 48-49 (2002) (“can be burnt directly or used as a fuel for gas engines and gas turbines. . . . The production of syngas from biomass allows the production of methanol and hydrogen.”) (internal citations omitted).
  53. ^ Badger, supra note 36 at 323.
  54. ^ Id. at 322
  55. ^ Michael Jacobson, Cedric Briens and Franco Berruti, “Lift tube technology for increasing heat transfer in an annular pyrolysis reactor”, CFB’9, Hamburg, Germany, May 13-16, 2008.
  56. ^ Yaman, Serdar, pyrolysis of biomass to produce fuels and chemical feedstocks, 45 Energy Conversion & MGMT 651, 659 (2003).
  57. ^ Cedric Briens, Jan Piskorz and Franco Berruti, Biomass Valorization for Fuel and Chemicals Production -- A Review, 2008. International Journal of Chemical Reactor Engineering, 6, R2.
  58. ^ Winsley, Peter, Biochar and bioenergy production for climate change mitigation, 64 NEW ZEALAND SCI. REV. 5 (2007) (See Table 1 for differences in output for Fast, Intermediate, Slow, and Gasification).
  59. ^ Id.
  60. ^ Laird, David A., The Charcoal Vision: A Win–Win–Win Scenario for Simultaneously Producing Bioenergy, Permanently Sequestering Carbon, while Improving Soil and Water Quality, AGRONOMY J., 100 178-181 (2008) (“The energy required to operate a fast pyrolyzer is ∼15% of the total energy that can be derived from the dry biomass. Modern systems are designed to use the syngas generated by the pyrolyzer to provide all the energy needs of the pyrolyzer.”)
  61. ^ Lehmann - Bioenergy in the Black, supra note 3.
  62. ^ Carbonscape “Describes microwave technology used to convert organic matter to biochar” (“Retrieved on 12 December 2008)
  63. ^ FAOSTAT 2006, available at http://faostat.fao.org/site/567/DesktopDefault.aspx?PageID=567 (accessed 1 July 2008) (production quantity of sugar cane in brazil in 2006).
  64. ^ Perera, K.K.C.K., P.G. Rathnasiri, S.A.S. Senarath, A.G.T. Sugathapala, S.C. Bhattacharya, and P. Abdul Salam, Assessment of sustainable energy potential of non-plantation biomass resources in Sri Lanka, 29 Biomass & Bioenergy 199, 204 (2005) (showing RPRs for numerous plants, describing method for determining available agricultural waste for energy and char production).
  65. ^ Laird, supra note 21 at 179 (“Much of the current scientific debate on the harvesting of biomass for bioenergy is focused on how much can be harvested without doing too much damage.”)
  66. ^ <doi:10.1016/S0961-9534(97)00014-7 Sugarcane leaf-bagasse gasifier for industrial heating applications. Biomass and Bioenergy, Vol 13, No.3, 1997.>
  67. ^ Ananthaswamy, Anil, Microwave factory to act as carbon sink, NEW SCIENTIST, 1 October (2008) (“Retrieved on 12 December 2008)
  68. ^ Biochar: Is the hype justified? By Roger Harrabin - Environment analyst, (09:20 GMT, Monday, 16 March 2009) BBC News
  69. ^ http://philadelphia.bizjournals.com/philadelphia/stories/2009/11/16/daily25.html
  70. ^ Austin, Anna (2009-09). "Mantria opens biochar plant in Tennessee". Biomass Magazine (BBI International). http://www.biomassmagazine.com/article.jsp?article_id=2992. Retrieved 2009-10-30. 
  71. ^ Austin, Anna (2009-10). "A New Climate Change Mitigation Tool". Biomass Magazine (BBI International). http://www.biomassmagazine.com/article.jsp?article_id=3091&q=&page=all. Retrieved 2009-10-30. 

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