Biochar

Biochar

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Biochar or terra preta is charcoal
Charcoal
Charcoal is the dark grey residue consisting of carbon, and any remaining ash, obtained by removing water and other volatile constituents from animal and vegetation substances. Charcoal is usually produced by slow pyrolysis, the heating of wood or other substances in the absence of oxygen...

 created by pyrolysis
Pyrolysis
Pyrolysis is a thermochemical decomposition of organic material at elevated temperatures without the participation of oxygen. It involves the simultaneous change of chemical composition and physical phase, and is irreversible...

 of biomass
Biomass
Biomass, as a renewable energy source, is biological material from living, or recently living organisms. As an energy source, biomass can either be used directly, or converted into other energy products such as biofuel....

. Biochar is under investigation as an approach to carbon sequestration via bio-energy with carbon capture and storage
Bio-energy with carbon capture and storage
Bio-energy with carbon capture and storage is a greenhouse gas mitigation technology which produces negative carbon emissions by combining biomass use with geologic carbon capture and storage....

. Biochar thus has the potential to help mitigate climate change
Climate change
Climate change is a significant and lasting change in the statistical distribution of weather patterns over periods ranging from decades to millions of years. It may be a change in average weather conditions or the distribution of events around that average...

, via carbon sequestration. Independently, biochar can increase soil fertility, raise agricultural productivity and reduce pressure on forest
Forest
A forest, also referred to as a wood or the woods, is an area with a high density of trees. As with cities, depending where you are in the world, what is considered a forest may vary significantly in size and have various classification according to how and what of the forest is composed...

s. Biochar is a stable solid, rich in carbon
Carbon
Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds...

 and can endure in soil for thousands of years.

History


Pre-Columbian
Pre-Columbian era
The pre-Columbian era incorporates all period subdivisions in the history and prehistory of the Americas before the appearance of significant European influences on the American continents, spanning the time of the original settlement in the Upper Paleolithic period to European colonization during...

 Amazonian
Amazon Rainforest
The Amazon Rainforest , also known in English as Amazonia or the Amazon Jungle, is a moist broadleaf forest that covers most of the Amazon Basin of South America...

s are believed to have used biochar to enhance soil productivity. They produced it by smoldering agricultural waste (i.e., covering burning biomass with soil) in pits or trenches. European settlers called it terra preta de Indio.
Following observations and experiments, a research team working in French Guiana
French Guiana
French Guiana is an overseas region of France, consisting of a single overseas department located on the northern Atlantic coast of South America. It has borders with two nations, Brazil to the east and south, and Suriname to the west...

 hypothesized that the Amazonian earthworm
Earthworm
Earthworm is the common name for the largest members of Oligochaeta in the phylum Annelida. In classical systems they were placed in the order Opisthopora, on the basis of the male pores opening posterior to the female pores, even though the internal male segments are anterior to the female...

 Pontoscolex corethrurus was the main agent of fine powdering and incorporation of charcoal debris to the mineral soil.

The term “biochar” was coined by Peter Read to describe charcoal used as a soil improvement.

Production


Pyrolysis produces biochar, liquids and gases from biomass by heating the biomass in a low/no oxygen
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...

 environment. The absence of oxygen prevents combustion
Combustion
Combustion or burning is the sequence of exothermic chemical reactions between a fuel and an oxidant accompanied by the production of heat and conversion of chemical species. The release of heat can result in the production of light in the form of either glowing or a flame...

. The relative yield of products from pyrolysis varies with temperature. Temperatures of 400–500 °C (752–932 F) produce more char
Char
Char is the solid material that remains after light gases and tar coal tar have been driven out or released from a carbonaceous material during the initial stage of combustion, which is known as carbonization, charring, devolatilization or pyrolysis.Further stages of efficient combustion are...

, while temperatures above 700 °C (1,292 °F) favor the yield of liquid and gas fuel components. Pyrolysis occurs more quickly at the higher temperatures, typically requiring seconds instead of hours. High temperature pyrolysis is also known as gasification
Gasification
Gasification is a process that converts organic or fossil based carbonaceous materials into carbon monoxide, hydrogen, carbon dioxide and methane. This is achieved by reacting the material at high temperatures , without combustion, with a controlled amount of oxygen and/or steam...

, and produces primarily syngas
Syngas
Syngas is the name given to a gas mixture that contains varying amounts of carbon monoxide and hydrogen. Examples of production methods include steam reforming of natural gas or liquid hydrocarbons to produce hydrogen, the gasification of coal, biomass, and in some types of waste-to-energy...

. Typical yields are 60% bio-oil, 20% biochar, and 20% syngas. By comparison, slow pyrolysis can produce substantially more char (~50%). Once initialized, both processes produce net energy. For typical inputs, the energy required to run a “fast” pyrolyzer is approximately 15% of the energy that it outputs. Modern pyrolysis plants can use the syngas created by the pyrolysis process and output 3–9 times the amount of energy required to run.

The Amazonian pit/trench method harvests neither bio-oil nor syngas, and releases a large amount of , black carbon
Black carbon
In Climatology, black carbon or BC is a climate forcing agent formed through the incomplete combustion of fossil fuels, biofuel, and biomass, and is emitted in both anthropogenic and naturally occurring soot. It consists of pure carbon in several linked forms...

, and other greenhouse gas
Greenhouse gas
A greenhouse gas is a gas in an atmosphere that absorbs and emits radiation within the thermal infrared range. This process is the fundamental cause of the greenhouse effect. The primary greenhouse gases in the Earth's atmosphere are water vapor, carbon dioxide, methane, nitrous oxide, and ozone...

es (GHG)s (and potentially, toxin
Toxin
A toxin is a poisonous substance produced within living cells or organisms; man-made substances created by artificial processes are thus excluded...

s) into the air. Commercial-scale systems process agricultural waste, paper byproducts, and even municipal waste and typically eliminate these side effects by capturing and using the liquid and gas products.

Centralized, decentralized and mobile systems


In a centralized system, all biomass in a region is brought to a central plant for processing. Alternatively, each farmer or group of farmers can operate a lower-tech kiln
Kiln
A kiln is a thermally insulated chamber, or oven, in which a controlled temperature regime is produced. Uses include the hardening, burning or drying of materials...

. Finally, a truck equipped with a pyrolyzer can move from place to place to pyrolyze biomass. Vehicle power comes from the syngas stream, while the biochar remains on the farm. The biofuel is sent to a refinery or storage site. Factors that influence the choice of system type include the cost of transportation of the liquid and solid byproducts, the amount of material to be processed, and the ability to feed directly into the power grid.

For crops that are not exclusively for biochar production, the residue-to-product ratio (RPR) and the collection factor (CF) the percent of the residue not used for other things, measure the approximate amount of feedstock that can be obtained for pyrolysis after harvesting the primary product. For instance, Brazil
Brazil
Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...

 harvests approximately 460 million tons (MT) of sugarcane
Sugarcane
Sugarcane refers to any of six to 37 species of tall perennial grasses of the genus Saccharum . Native to the warm temperate to tropical regions of South Asia, they have stout, jointed, fibrous stalks that are rich in sugar, and measure two to six metres tall...

 annually, with an RPR of 0.30, and a CF of 0.70 for the sugarcane tops, which are normally burned in the field. This translates into approximately 100 MT of residue annually which could be pyrolyzed to create energy and soil additives. Adding in the bagasse
Bagasse
Bagasse is the fibrous matter that remains after sugarcane or sorghum stalks are crushed to extract their juice. It is currently used as a biofuel and as a renewable resource in the manufacture of pulp and paper products and building materials....

 (sugarcane waste) (RPR=0.29 CF=1.0) which is otherwise burned (inefficiently) in boilers, raises the total to 230 MT of pyrolysis feedstock. Some plant residue, however, must remain on the soil to avoid increased costs and emissions from nitrogen fertilizers.

Pyrolysis technologies for processing loose and leafy biomass produce both biochar and syngas.

Thermo catalytic depolymerization


Alternatively, thermo-catalytic depolymerization using microwave
Dielectric heating
Dielectric heating, also known as electronic heating, RF heating, high-frequency heating and diathermy, is the process in which a high-frequency alternating electric field, or radio wave or microwave electromagnetic radiation heats a dielectric material. At higher frequencies, this heating is...

s has recently been used to efficiently convert organic matter to biochar on an industrial scale, producing ~50% char.

Carbon sink


The burning and natural decomposition of biomass and in particular agricultural waste adds large amounts of and to the atmosphere. Biochar can store large amounts of greenhouse gases in the ground, potentially reducing or stalling the growth 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.

Biochar can sequester carbon in the soil for hundreds to thousands of years, like coal
Coal
Coal is a combustible black or brownish-black sedimentary rock usually occurring in rock strata in layers or veins called coal beds or coal seams. The harder forms, such as anthracite coal, can be regarded as metamorphic rock because of later exposure to elevated temperature and pressure...

. This technique is advocated by prominent scientists such as James Hansen
James Hansen
James E. Hansen heads the NASA Goddard Institute for Space Studies in New York City, a part of the Goddard Space Flight Center in Greenbelt, Maryland. He has held this position since 1981...

, head of the NASA Goddard Institute for Space Studies
Goddard Institute for Space Studies
The NASA Goddard Institute for Space Studies , at Columbia University in New York City, is a component laboratory of NASA's Goddard Space Flight Center Earth-Sun Exploration Division and a unit of The Earth Institute at Columbia University...

, and James Lovelock
James Lovelock
James Lovelock, CH, CBE, FRS is an independent scientist, environmentalist and futurologist who lives in Devon, England. He is best known for proposing the Gaia hypothesis, which postulates that the biosphere is a self-regulating entity with the capacity to keep our planet healthy by controlling...

, creator of the Gaia hypothesis
Gaia hypothesis
The Gaia hypothesis, also known as Gaia theory or Gaia principle, proposes that all organisms and their inorganic surroundings on Earth are closely integrated to form a single and self-regulating complex system, maintaining the conditions for life on the planet.The scientific investigation of the...

, for mitigation of global warming
Mitigation of global warming
Climate change mitigation is action to decrease the intensity of radiative forcing in order to reduce the potential effects of global warming. Mitigation is distinguished from adaptation to global warming, which involves acting to tolerate the effects of global warming...

 by greenhouse gas remediation
Greenhouse gas remediation
Greenhouse gas remediation projects are a type of geoengineering and seek to remove greenhouse gases from the atmosphere, and thus tackle the root cause of global warming. These techniques either directly remove greenhouse gases, or alternatively seek to influence natural processes to remove...

.

Biochar can sequester carbon in the soil for hundreds to thousands of years, this storage property of carbon has received considerable interest as a potential tool to slow global warming. The IPCC Fourth Assessment Report
IPCC Fourth Assessment Report
Climate Change 2007, the Fourth Assessment Report of the United Nations Intergovernmental Panel on Climate Change , is the fourth in a series of reports intended to assess scientific, technical and socio-economic information concerning climate change, its potential effects, and options for...

 includes Biochar as a key technology for reaching low carbon dioxide atmospheric concentration targets. The negative emissions that can be produced by bio-energy with carbon capture and storage (BECCS) has been estimated by the Royal Society
Royal Society
The Royal Society of London for Improving Natural Knowledge, known simply as the Royal Society, is a learned society for science, and is possibly the oldest such society in existence. Founded in November 1660, it was granted a Royal Charter by King Charles II as the "Royal Society of London"...

 to be equivalent to a 50 to 150 ppm decrease in global atmospheric carbon dioxide concentrations
Carbon dioxide in the Earth's atmosphere
The concentration of carbon dioxide in Earth's atmosphere is approximately 392 ppm by volume and rose by 2.0 ppm/yr during 2000–2009. 40 years earlier, the rise was only 0.9 ppm/yr, showing not only increasing concentrations, but also a rapid acceleration of concentrations...

.

Annual net emissions of carbon dioxide , methane and nitrous oxide could be reduced by a maximum of 1.8 Pg -C equivalent (-C) per year (12% of current anthropogenic -Ce emissions; 1 Pg=1 Gt), and total net emissions over the course of a century by 130 Pg -Ce, without endangering food security, habitat or soil conservation.
According to the International Energy Agency
International Energy Agency
The International Energy Agency is a Paris-based autonomous intergovernmental organization established in the framework of the Organisation for Economic Co-operation and Development in 1974 in the wake of the 1973 oil crisis...

, the BLUE map climate change mitigation scenario
Climate change mitigation scenarios
Climate change mitigation scenarios are possible futures in which global warming is reduced by deliberate actions, such as a comprehensive switch to energy sources other than fossil fuels...

 calls for more than 2 gigatons of negative emissions per year with BECCS in 2050.

Biochar is a high-carbon, fine-grained residue which today is produced through modern pyrolysis processes. Pyrolysis is the direct thermal decomposition
Thermal decomposition
Thermal decomposition, or thermolysis, is a chemical decomposition caused by heat. The decomposition temperature of a substance is the temperature at which the substance chemically decomposes....

 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. Even when optimized to produce char rather than energy, the energy produced per unit energy input is higher than for corn ethanol
Corn ethanol
Corn ethanol is ethanol produced from corn as a biomass through industrial fermentation, chemical processing and distillation. Corn is the main feedstock used for producing ethanol fuel in the United States and it is mainly used as an oxygenate to gasoline in the form of low-level blends, and to a...

.

Soil amendment


Biochar can be used as a soil amendment
Soil conditioner
A soil conditioner, also called a soil amendment, is a material added to soil to improve plant growth and health. A conditioner or a combination of conditioners corrects the soil's deficiencies in structure and-or nutrients.-Purpose:...

 to improve yield, but only for plants that require high potash
Potash
Potash is the common name for various mined and manufactured salts that contain potassium in water-soluble form. In some rare cases, potash can be formed with traces of organic materials such as plant remains, and this was the major historical source for it before the industrial era...

 and elevated pH
PH
In chemistry, pH is a measure of the acidity or basicity of an aqueous solution. Pure water is said to be neutral, with a pH close to 7.0 at . Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline...

, improve water quality, reduce soil emissions of greenhouse gases, reduce nutrient leaching, reduce soil acidity, and reduce irrigation
Irrigation
Irrigation may be defined as the science of artificial application of water to the land or soil. It is used to assist in the growing of agricultural crops, maintenance of landscapes, and revegetation of disturbed soils in dry areas and during periods of inadequate rainfall...

 and fertilizer
Fertilizer
Fertilizer is any organic or inorganic material of natural or synthetic origin that is added to a soil to supply one or more plant nutrients essential to the growth of plants. A recent assessment found that about 40 to 60% of crop yields are attributable to commercial fertilizer use...

 requirements.

These positive qualities are dependent on the properties of the biochar, and may depend on regional conditions including soil type, soil condition (depleted or healthy), temperature, and humidity. Modest additions of biochar to soil reduce nitrous oxide
Nitrous oxide
Nitrous oxide, commonly known as laughing gas or sweet air, is a chemical compound with the formula . It is an oxide of nitrogen. At room temperature, it is a colorless non-flammable gas, with a slightly sweet odor and taste. It is used in surgery and dentistry for its anesthetic and analgesic...

  emissions by up to 80% and eliminate methane
Methane
Methane is a chemical compound with the chemical formula . It is the simplest alkane, the principal component of natural gas, and probably the most abundant organic compound on earth. The relative abundance of methane makes it an attractive fuel...

 emissions, which are both more potent greenhouse gases than .

Pollutants such as metals and pesticide
Pesticide
Pesticides are substances or mixture of substances intended for preventing, destroying, repelling or mitigating any pest.A pesticide may be a chemical unicycle, biological agent , antimicrobial, disinfectant or device used against any pest...

s seep into soil and contaminate food supplies, reducing the amount of land suitable for agricultural production. Studies have reported positive effects from biochar on crop production in degraded and nutrient–poor soils. Biochar can be designed with specific qualities to target distinct properties of soils. Biochar reduces leaching of critical nutrients, creates a higher crop uptake of nutrients, and provides greater soil availability of nutrients. At 10% levels biochar reduced contaminant levels in plants by up to 80%, while reducing total chlordane
Chlordane
Chlordane, or chlordan, is an organochlorine compound that was used as a pesticide. This white solid was sold in the U.S. until 1983 as an insecticide for crops like corn and citrus and on lawns and domestic gardens.-Production and uses:...

 and DDX content in the plants by 68 and 79%, respectively.

Slash and char


Switching from slash and burn
Slash and burn
Slash-and-burn is an agricultural technique which involves cutting and burning of forests or woodlands to create fields. It is subsistence agriculture that typically uses little technology or other tools. It is typically part of shifting cultivation agriculture, and of transhumance livestock...

to slash and char techniques in Brazil can decrease both deforestation of the Amazon basin
Amazon Basin
The Amazon Basin is the part of South America drained by the Amazon River and its tributaries that drains an area of about , or roughly 40 percent of South America. The basin is located in the countries of Bolivia, Brazil, Colombia, Ecuador, Guyana, Peru, and Venezuela...

 and carbon dioxide emission, as well as increase crop yields. Slash and burn leaves only 3% of the carbon from the organic material in the soil.

Slash and char can sequester up to 50% of the carbon in a highly stable form. Returning the biochar into the soil rather than removing it all for energy production reduces the need for nitrogen fertilizers, thereby reducing cost and emissions from fertilizer production and transport. Additionally, by improving the soil tilth
Tilth
Tilth can refer to two things:Tillage and a measure of the health of soil.Good tilth is a term referring to soil that has the proper structure and nutrients to grow healthy crops. Soil in good tilth is loamy, nutrient-rich soil that can also be said to be friable because optimal soil has a mixture...

, fertility, and productivity, biochar – enhanced soils can indefinitely sustain agricultural production, whereas non-amended soils quickly become depleted of nutrients, forcing farmers to abandon the fields. This produces a continuous slash and burn cycle and the continued loss of tropical rainforest
Tropical rainforest
A tropical rainforest is an ecosystem type that occurs roughly within the latitudes 28 degrees north or south of the equator . This ecosystem experiences high average temperatures and a significant amount of rainfall...

. Using pyrolysis to produce bio-energy also has the added benefit of not requiring infrastructure changes the way processing biomass for cellulosic ethanol
Cellulosic ethanol
Cellulosic ethanol is a biofuel produced from wood, grasses, or the non-edible parts of plants.It is a type of biofuel produced from lignocellulose, a structural material that comprises much of the mass of plants. Lignocellulose is composed mainly of cellulose, hemicellulose and lignin...

 does. Additionally, the biochar produced can be applied by the currently used tillage machinery or equipment used to apply fertilizer.

Energy production: bio-oil & syngas


Bio-oil can be used as a replacement for numerous applications where fuel oil is used, including fueling space heaters, furnace
Furnace
A furnace is a device used for heating. The name derives from Latin fornax, oven.In American English and Canadian English, the term furnace on its own is generally used to describe household heating systems based on a central furnace , and sometimes as a synonym for kiln, a device used in the...

s, and boiler
Boiler
A boiler is a closed vessel in which water or other fluid is heated. The heated or vaporized fluid exits the boiler for use in various processes or heating applications.-Materials:...

s. Additionally, these biofuels can be used to fuel some combustion turbines and reciprocating engines, and as a source to create several chemicals. 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
Biodiesel
Biodiesel refers to a vegetable oil- or animal fat-based diesel fuel consisting of long-chain alkyl esters. Biodiesel is typically made by chemically reacting lipids with an alcohol....

 and gasoline substitutes. 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. Syngas can be burned directly, used as a fuel for gas engines and gas turbines, converted to clean diesel fuel
Ultra-low sulfur diesel
Ultra-low-sulfur diesel is a term used to describe diesel fuel with substantially lowered sulfur content...

 through the Fischer–Tropsch process or potentially used in the production of methanol
Methanol
Methanol, also known as methyl alcohol, wood alcohol, wood naphtha or wood spirits, is a chemical with the formula CH3OH . It is the simplest alcohol, and is a light, volatile, colorless, flammable liquid with a distinctive odor very similar to, but slightly sweeter than, ethanol...

 and hydrogen
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...

.

Bio-oil has a much higher energy density than the raw biomass material. 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. 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. 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.

Research


Further research is in progress, notably by Cornell University
Cornell University
Cornell University is an Ivy League university located in Ithaca, New York, United States. It is a private land-grant university, receiving annual funding from the State of New York for certain educational missions...

 and the University of Georgia
University of Georgia
The University of Georgia is a public research university located in Athens, Georgia, United States. Founded in 1785, it is the oldest and largest of the state's institutions of higher learning and is one of multiple schools to claim the title of the oldest public university in the United States...

, which has a dedicated research unit.

Students at Stevens Institute of Technology
Stevens Institute of Technology
Stevens Institute of Technology is a technological university located on a campus in Hoboken, New Jersey, USA – founded in 1870 with an 1868 bequest from Edwin A. Stevens. It is known for its engineering, science, and technological management curricula.The institute has produced leading...

 in New Jersey are developing supercapacitor
Supercapacitor
An electric double-layer capacitor , also known as supercapacitor, supercondenser, electrochemical double layer capacitor, or ultracapacitor, is an electrochemical capacitor with relatively high energy density. Their energy density is typically hundreds of times greater than conventional...

s that use electrodes made of biochar. A process developed by University of Florida
University of Florida
The University of Florida is an American public land-grant, sea-grant, and space-grant research university located on a campus in Gainesville, Florida. The university traces its historical origins to 1853, and has operated continuously on its present Gainesville campus since September 1906...

 researchers which removes phosphate
Phosphate
A phosphate, an inorganic chemical, is a salt of phosphoric acid. In organic chemistry, a phosphate, or organophosphate, is an ester of phosphoric acid. Organic phosphates are important in biochemistry and biogeochemistry or ecology. Inorganic phosphates are mined to obtain phosphorus for use in...

 from water, also yields methane gas usable as fuel and phosphate-laden carbon suitable for enriching soil.

Emerging commercial sector


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. As of mid-February 2010, CO2 is trading
Emissions trading
Emissions trading is a market-based approach used to control pollution by providing economic incentives for achieving reductions in the emissions of pollutants....

 at $16.82/ton on the European Climate Exchange
European Climate Exchange
The European Climate Exchange manages the product development and marketing for ECX Carbon Financial Instruments , listed and admitted for trading on the ICE Futures Europe electronic platform. It is no longer a subsidiary of the Chicago Climate Exchange but rather a sister company...

 (ECX), so using pyrolysis for bioenergy production may be feasible even if it is more expensive than fossil fuel
Fossil fuel
Fossil fuels are fuels formed by natural processes such as anaerobic decomposition of buried dead organisms. The age of the organisms and their resulting fossil fuels is typically millions of years, and sometimes exceeds 650 million years...

s.

Pyrolysis does have costs associated with the machinery and heating (around US$4 per gigajoule) and is dependent on a supply of cheap biomass. At the local or field scale, biochar can usefully enhance existing sequestration approaches. It can be mixed with manures or fertilizers and included in no-tillage methods, without the need for additional equipment. Biochar has been shown to improve the structure and fertility of soils, thereby improving biomass production. Biochar not only enhances the retention and therefore efficiency of fertilizers but may, by the same mechanism, also decrease fertilizer run-off. For biochar sequestration to work on a much larger scale, an important factor is combining low-temperature pyrolysis with simultaneous capture of the exhaust gases and converting them to energy as heat, electricity, biofuel or hydrogen. Depending on the feedstock used and bioenergy produced, low-temperature pyrolysis with gas capture (but no sequestra- tion) can be a carbon-neutral energy source. Most companies that generate bioenergy in this way view biochar merely as a byproduct that can itself be burned to offset fossil-fuel use and reduce costs. But our calculations suggest that emissions reductions can be 12–84% greater if biochar is put back into the soil instead of being burned to offset fossil-fuel use. Biochar sequestration offers the chance to turn bioenergy into a carbon-negative industry.

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
Geoengineering
The concept of Geoengineering refers to the deliberate large-scale engineering and manipulation of the planetary environment to combat or counteract anthropogenic changes in atmospheric chemistry The Intergovernmental Panel on Climate Change concluded in 2007 that geoengineering options, such...

 approach. 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
Central Africa
Central Africa is a core region of the African continent which includes Burundi, the Central African Republic, Chad, the Democratic Republic of the Congo, and Rwanda....

. In this concept, biochar is a tool used to simultaneously slow down deforestation
Deforestation
Deforestation is the removal of a forest or stand of trees where the land is thereafter converted to a nonforest use. Examples of deforestation include conversion of forestland to farms, ranches, or urban use....

, increase the food security
Food security
Food security refers to the availability of food and one's access to it. A household is considered food-secure when its occupants do not live in hunger or fear of starvation. According to the World Resources Institute, global per capita food production has been increasing substantially for the past...

 of rural communities, provide renewable energy
Renewable energy
Renewable energy is energy which comes from natural resources such as sunlight, wind, rain, tides, and geothermal heat, which are renewable . About 16% of global final energy consumption comes from renewables, with 10% coming from traditional biomass, which is mainly used for heating, and 3.4% from...

 to them and sequester carbon.

Various companies in North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

, Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

 and England
England
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...

 sell biochar and/or biochar production units.

The 2009 International Biochar Conference in Boulder, Colorado
Boulder, Colorado
Boulder is the county seat and most populous city of Boulder County and the 11th most populous city in the U.S. state of Colorado. Boulder is located at the base of the foothills of the Rocky Mountains at an elevation of...

 saw the launch of a mobile pyrolysis unit with a specified intake of 1,000 pounds per hour (450 kg per hour). The unit, with a length of 12 feet and height of 7 feet (3.6 m by 2.1m), was intended for agricultural applications.

A unit which opened in Dunlap, Tennessee
Dunlap, Tennessee
Dunlap is a city in Sequatchie County, Tennessee, United States. The population was 4,173 at the 2000 census. It is the county seat of Sequatchie County.Dunlap is part of the Chattanooga, TN–GA Metropolitan Statistical Area.-Geography:...

 in August 2009 after testing and an initial run, was subsequently shut down as part of a Ponzi scheme
Ponzi scheme
A Ponzi scheme is a fraudulent investment operation that pays returns to its investors from their own money or the money paid by subsequent investors, rather than from any actual profit earned by the individual or organization running the operation...

 investigation.

See also


  • Vertical farming
    Vertical farming
    Vertical farming is a concept that argues that it is economically and environmentally viable to cultivate plant or animal life within skyscrapers, or on vertically inclined surfaces...

  • Soil carbon
    Soil carbon
    Soil carbon is the generic name for carbon held within the soil, primarily in association with its organic content. Soil carbon is the largest terrestrial pool of carbon. Humans have, and will likely continue to have, significant impacts on the size of this pool...

  • Soil ecology
    Soil ecology
    Soil ecology is the study of the interactions among soil organisms, and between biotic and abiotic aspects of the soil environment. It is particularly concerned with the cycling of nutrients, formation and stabilization of the pore structure, the spread and vitality of pathogens, and the...


External links


Biochar organisations by country