Organic matter, such as agricultural waste, heated in the absence of oxygen splits into two types of material: a charcoal (biochar), and hydrocarbon gases and liquids. When added to soils, the charcoal can provide a powerful fertiliser. The hydrocarbons can be burnt, either to generate electricity or to power an internal combustion engine.
Biochar is exciting growing attention around the world. Charcoal’s ability to improve soils can sometimes be spectacular. But more importantly from a climate change perspective, charcoal is almost pure carbon and is strangely stable in soils. It seems to persist for centuries. Charcoal can therefore offer substantial opportunities for long-term sequestration of carbon. The valuable fuels from the biogases and liquids are also carbon-neutral since they contain CO2 previously captured during photosynthesis. As a third major benefit, soils fertilised with charcoal seem to need less artificial fertiliser, thus saving fossil fuels. Fewer applications of fertiliser would reduce the level of emissions of nitrous oxide, a particularly dangerous greenhouse gas.
Biochar manufacture represents a way of productively storing large amounts of carbon. But the carbon in the charcoal could be burnt to generate electricity instead of being stored in soil. Current emissions trading schemes, such as the European ETS, do not allow sequestered carbon to be considered as equivalent to a reduction in greenhouse warming emissions. This is a mistake that will need to be rectified. It make more sense to use agricultural land to make biochar and biogases/bioliquids than to burn the biomass in power stations. Power stations burning wood benefit from buying fewer emissions certificates and from the renewable energy subsidy, but there is no comparable benefit from storing carbon in the soil. This is an anomaly that should be removed.
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Some Amazonian soils are extremely rich and fertile. Thick and almost black, these soils contain a high percentage of very stable carbon. The pre-Columbian population appears to have fed their naturally thin soils with large amounts of charcoal which have remained until today. Known as ‘terra preta’ soils, they have remained fertile for hundreds of years after the application of carbon in the form of charcoal.
Researchers have noted that charcoals can improve soil productivity in other soils around the world. No one quite understands the process, and a great deal more scientific work needs to be done, but the evidence is strong that the highly porous structure of biochar helps retain other nutrients and provides a protective structure that encourages the growth of beneficial micro-fungi. Its sponge-like porosity gives it a huge surface area on to which nutrients and useful organisms can cling. Biochar that has been laced with applications of potassium and phosphorus appears to achieve even better results than the simple charcoal. (See http://www.eprida.com/.)
Established terra preta soils have high productivity. Yields can be more than twice those of adjacent areas to which charcoal has not been applied. From the point of view of improving soil fertility, it may make good sense to apply biochar to a large percentage of the world’s soils.
How to make biochar
Wood and other organic residues such as crop wastes can be burnt in air, and will leave a small amount of black charcoal. Most of the carbon in the organic matter is burnt, generating heat, carbon dioxide, and other gases. Unlike biochar, the carbon that is left unburnt tends to be quite quickly digested by the soil.
Heating in the absence of air is usually called ‘pyrolysis’. (Much oven cooking occurs as pyrolysis. The external layer of the food seals the inside from oxygen.) During pyrolysis, the heat drives off hydrocarbon gases and liquids (as well as the remaining water). Eventually, all that is left is biochar, which can be almost pure carbon. The carbon at the end of the pyrolysis process can represent as much as 50% of the original weight of the organic waste. The percentage depends on the original material and on the temperature to which it was heated.
Pyrolysis can be carried out on a very small scale, producing charcoal and gases for cooking use. In the past, the charcoal would have been employed as an efficient source of heat for other uses, whether metal smelting or the cooking of food. The challenge now is to produce equipment that can handle hundreds of tonnes of bio-waste or wood residues every day. Some businesses are well on the way.
In today’s pilot plants, the original organic material passes through sealed vessels to which heat is applied. This heat may be derived from burning the gases driven off in previous pyrolysis. The hydrocarbons are collected, either as gas or as liquid and the solid material is then cooled and crushed into very fine carbon granules.
Dynamotive in Canada and BEST Pyrolysis (Australia/US) are making good progress towards commercial-scale plants processing hundreds of tonnes of material a day. I don’t doubt that large industrial-scale biochar manufacturing facilities will be successfully developed within three or four years. This area is already attracting substantial sums of private capital, and the technological challenges are not of the greatest difficulty. The crucial determinant of whether the sequestration of biochar becomes a large-scale worldwide activity is financial. Does it make sense to store charcoal in soil rather than burn it?
The financial value of biochar
The short section that follows contains dense financial calculations. Its purpose is simply to say that:
- Emissions trading schemes should incorporate carbon sequestration in the soil as a valid reduction in CO2.
- The current UK system for subsidising renewable electricity generation is extremely generous to the burning of renewable fuels. The system offers a misplaced incentive to use charcoal to burn in power stations rather than store it in the soil, although the net effect on carbon emissions will be approximately equal.
For those interested, here are the numbers:
A tonne of good quality biochar has an energy value of about 28 gigajoules (GJ), slightly less than the best quality coal. (Pure black carbon is about 32 GJ/tonne.) Standard coal costs about £1.50 per GJ. If a power station operator is prepared to pay the coal-equivalent price, biochar is worth about £42 per tonne in the UK.
Burning a tonne of biochar will produce about three and a half tonnes of CO2. (Pure carbon would generate 3.667 tonnes.) The current price of CO2 in the European Emissions Trading Scheme (ETS) is about £16, meaning that sequestering 3.5 tonnes ought to be worth approximately £56. Since £56 is greater than £42, the economic logic suggests that we should hold the carbon in the soil rather than burning it. This is before considering the secondary climate change benefits of reduced fertiliser use and lowered nitrous oxide emissions.
Of course, today it isn’t yet possible to make the rational choice and plough biochar into the soil. The farmer cannot gain credit for sequestering organic matter in this way. The ETS doesn’t recognise the storing of inert carbon as a valid way of reducing emissions. So charcoal gets burnt in the UK, rather than being stored. This needs to change: sequestering biochar in the soil is a reasonably inexpensive way of reducing net CO2 emissions.
In fact, the position is far more illogical even than this. If a power station burns an ‘energy crop’, such as willow or miscanthus grass, it gets two Renewable Obligation Certificates per MWh generated, worth over £90. Per tonne of biochar used in a specialist biomass power station, such as E.ON’s at Lockerbie, the power station operator will generate about 2.3 MWh, and therefore get ROCs to the value of over £200. Carbon Commentary has written before about the excessive generosity of this arrangement – please see issue 1 of this newsletter.
The net effect of the subsidy regime in the UK is that charcoal sequestration is financially unattractive before considering the benefits in terms of reduced fertiliser use. But in terms of the underlying carbon saving, it would be better to plough the char into the soil.
Weighing the climate change benefit of smaller amounts of fertiliser
Artificial fertilisers are bad for global warming because they take substantial amounts of natural gas to make, and because they seem to cause greater amounts of nitrous oxide to be emitted from fields and local watercourses as the fertiliser breaks down. Nitrous oxide has over 300 times the global warming effect of CO2. It may be that at least 2% of the nitrogen in fertiliser ends up in the form of nitrous oxide after being applied on a damp British field.
I have seen no complete studies of how much it might be possible to reduce fertiliser use by adding biochar to a field. But a few illustrative numbers might be helpful. A hectare of wheat gets about 200kg of fertiliser a year. The CO2 cost of making this is something over 1 tonne. The nitrous oxide effect might triple this. In the ETS, four tonnes of CO2 costs perhaps £64. So even if biochar meant that the farmer could completely get rid of fertilisers, it would still only have a small CO2 benefit if all the emissions were valued at current prices. All available biochar would still probably be burnt for its value in ROCs.
The more interesting question is whether agricultural yields would go up. Terra preta soils succeed partly because they have much higher carbon content than other land in the same area. UK soils already have reasonable carbon content, so the impact of biochar is likely to be much less. We need further research on this urgently.
In Australia soil carbon levels are generally very low. There the value of adding biochar may be very much greater. Unsurprisingly, a good portion of the research into adding charcoal to soils is being carried out in Australian universities and companies.
Could sequestering biochar make a big difference to UK emissions?
The answer to this question is quite complicated, but broadly speaking the answer is yes. Soil used to grow miscanthus grass can produce about 20 tonnes of organic matter per year. Burnt in a low temperature pyrolysis furnace, this grass will give off substantial amount of gas and liquids that can be burnt as fuel, reducing fossil fuel use. This has value, and replaces fossil fuel. About 10 tonnes of char might be left, producing 35 tonnes of CO2 if it had been burnt, per hectare. To sequester 70 million tonnes of CO2, or somewhat over 10% of UK emissions per year, we would need to devote about 2m hectares to growing grasses or fast-growing willow for turning into charcoal. The UK has about 19m hectares of land in agricultural use of which over 7m is used as grassland. In other words, we probably could sequester the equivalent of 10% of our emissions every year, but it would need us to convert a lot of low-value grazing land to miscanthus. We’d get additional benefits from improved soil fertility, lowered fertiliser use, and the benefit of burning the biogas and bioliquid.
It is probably more important to get people in the tropics using biochar for soil improvement. Tropical agriculture often uses ‘slash and burn’ for clearing an area prior to cultivation. Changing this to ‘slash and char’ would sequester most of the carbon, and increase the number of years the soil could be used before the farmer moved to other land. The potential in the tropics for carbon sequestration is far greater than in high latitudes.
Biochar appears to have real significance as a technique for reducing emissions around the globe. The case for substantial investment in R+D, as well as changing the regulatory incentives to sequester carbon, is overwhelming.
(Readers interested in learning more about the worldwide research into biochar may like to go first to the web site of Cornell professor Johannes Lehmann, a leading figure in the scientific investigation: http://www.css.cornell.edu/faculty/lehmann/terra_preta/TerraPretahome.htm.)
Tags: agriculture, BEST Pyrolysis, biochar, carbon capture, carbon reduction initiatives, Dynamotive, emissions trading, ROCs
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I hope you will come to share my passion in getting the word out on the wonderful solutions provided by TP soils.
I’m sort of the TP list cub reporter, most all my list postings, under shengar@aol.com, are news items, collaborative work, lobbying efforts with government, writers and journals.Bellow are my collected stories and links that I promiscuously post to anyone who has an iron in this fire.
Thanks for your interest
Cheers,
Erichthe current news and links on Terra Preta (TP) soils and closed-loop pyrolysis of Biomass, this integrated virtuous cycle could sequester 100s of Billions of tons of carbon to the soils.
This technology represents the most comprehensive, low cost, and productive approach to long term stewardship and sustainability.Terra Preta Soils a process for Carbon Negative Bio fuels, massive Carbon sequestration, 1/3 Lower CH4 & N2O soil emissions, and 3X Fertility Too.
UN Climate Change Conference: Biochar present at the Bali Conference
http://terrapreta.bioenergylists.org/steinerbalinov2107
SCIAM Article May 15 07;
http://www.sciam.com/article.cfm?articleID=5670236C-E7F2-99DF-3E2163B9FB144E40
After many years of reviewing solutions to anthropogenic global warming (AGW) I believe this technology can manage Carbon for the greatest collective benefit at the lowest economic price, on vast scales. It just needs to be seen by ethical globally minded companies.
Could you please consider looking for a champion for this orphaned Terra Preta Carbon Soil Technology.
The main hurtle now is to change the current perspective held by the IPCC that the soil carbon cycle is a wash, to one in which soil can be used as a massive and ubiquitous Carbon sink via Charcoal. Below are the first concrete steps in that direction;
S.1884 – The Salazar Harvesting Energy Act of 2007
A Summary of Biochar Provisions in S.1884:
Carbon-Negative Biomass Energy and Soil Quality Initiative
for the 2007 Farm Bill
http://www.biochar-international.org/newinformationevents/newlegislation.html
Bolstering Biomass and Biochar development: In the 2007 Farm Bill, Senator Salazar was able to include $500 million for biomass research and development and for competitive grants to develop the technologies and processes necessary for the commercial production of biofuels and bio-based products. Biomass is an organic material, usually referring to plant matter or animal waste. Using biomass for energy can reduce waste and air pollution. Biochar is a byproduct of producing energy from biomass. As a soil treatment, it enhances the ability of soil to capture and retain carbon dioxide.
Tackling Climate Change in the U.S.
Potential Carbon Emissions Reductions from Biomass by 2030by Ralph P. Overend, Ph.D. and Anelia Milbrandt
National Renewable Energy Laboratoryhttp://www.ases.org/climatechange/toc/07_biomass.pdf
The organization 25×25 released it’s (first-ever, 55-page )”Action Plan” ; see; http://www.25×25.org/storage/25×25/documents/IP%20Documents/ActionPlanFinalWEB_04-19-07.pdf
On page 29 , as one of four foci for recommended RD&D, the plan lists: “The development of biochar, animal agriculture residues and other non-fossil fuel based fertilizers, toward the end of integrating energy production with enhanced soil quality and carbon sequestration.”
and on p 32, recommended as part of an expanded database aspect of infrastructure: “Information on the application of carbon as fertilizer and existing carbon credit trading systems.”I feel 25×25 is now the premier US advocacy organization for all forms of renewable energy, but way out in front on biomass topics.
There are 24 billion tons of carbon controlled by man in his agriculture and waste stream, all that farm & cellulose waste which is now dumped to rot or digested or combusted and ultimately returned to the atmosphere as GHG should be returned to the Soil.
Even with all the big corporations coming to the GHG negotiation table, like Exxon, Alcoa, .etc, we still need to keep watch as they try to influence how carbon management is legislated in the USA. Carbon must have a fair price, that fair price and the changes in the view of how the soil carbon cycle now can be used as a massive sink verses it now being viewed as a wash, will be of particular value to farmers and a global cool breath of fresh air for us all.
If you have any other questions please feel free to call me or visit the TP web site I’ve been drafted to co-administer. http://terrapreta.bioenergylists.org/?q=node
It has been immensely gratifying to see all the major players join the mail list , Cornell folks, T. Beer of Kings Ford Charcoal (Clorox), Novozyne the M-Roots guys(fungus), chemical engineers, Dr. Danny Day of EPRIDA , Dr. Antal of U. of H., Virginia Tech folks and probably many others who’s back round I don’t know have joined.
Also Here is the Latest BIG Terra Preta Soil news;
The Honolulu Advertiser: “The nation’s leading manufacturer of charcoal has licensed a University of Hawai’i process for turning green waste into barbecue briquets.”
See: http://terrapreta.bioenergylists.org/antalkingsford
ConocoPhillips Establishes $22.5 Million Pyrolysis Program at Iowa State
http://www.conocophillips.com/newsroom/news_releases/2007news/04-10-2007.htmGlomalin, the recently discovered soil protien, may be the secret to to TP soils productivity;
http://www.ars.usda.gov/is/pr/2003/030205.htm
Mycorrhizae Inoculent;
The International Biochar Initiative (IBI) conference held at Terrigal, NSW, Australia in 2007. The papers from this conference are posted at their home page; http://www.biochar-international.org/home.html
Here is my current Terra Preta posting which condenses the most important stories and links;
Terra Preta Soils Technology To Master the Carbon Cycle
Man has been controlling the carbon cycle , and there for the weather, since the invention of agriculture, all be it was as unintentional, as our current airliner contrails are in affecting global dimming. This unintentional warm stability in climate has over 10,000 years, allowed us to develop to the point that now we know what we did,………… and that now……… we are over doing it.
The prehistoric and historic records gives a logical thrust for soil carbon sequestration.
I wonder what the soil biome carbon concentration was REALLY like before the cutting and burning of the world’s forest, my guess is that now we see a severely diminished community, and that only very recent Ag practices like no-till and reforestation have started to help rebuild it. It makes implementing Terra Preta soil technology like an act of penitence, a returning of the misplaced carbon to where it belongs.On the Scale of CO2 remediation:
It is my understanding that atmospheric CO2 stands at 379 PPM, to stabilize the climate we need to reduce it to 350 PPM by the removal of 230 Billion tons of carbon.
The best estimates I’ve found are that the total loss of forest and soil carbon (combined
pre-industrial and industrial) has been about 200-240 billion tons. Of
that, the soils are estimated to account for about 1/3, and the vegetation
the other 2/3.Since man controls 24 billion tons in his agriculture then it seems we have plenty to work with in sequestering our fossil fuel CO2 emissions as stable charcoal in the soil.
As Dr. Lehmann at Cornell points out, “Closed-Loop Pyrolysis systems such as Dr. Danny Day’s are the only way to make a fuel that is actually carbon negative”. and that ” a strategy combining biochar with biofuels could ultimately offset 9.5 billion tons of carbon per year-an amount equal to the total current fossil fuel emissions! ”
Terra Preta Soils Carbon Negative Bio fuels, massive Carbon sequestration, 1/3 Lower CH4 & N2O soil emissions, and 3X FertilityToo
This some what orphaned new soil technology speaks to so many different interests and disciplines that it has not been embraced fully by any. I’m sure you will see both the potential of this system and the convergence needed for it’s implementation.
The integrated energy strategy offered by Charcoal based Terra Preta Soil technology may
provide the only path to sustain our agricultural and fossil fueled power
structure without climate degradation, other than nuclear power.The economics look good, and truly great if we had CO2 cap & trade or a Carbon tax in place.
.Nature article, Aug 06: Putting the carbon back Black is the new green:
http://bestenergies.com/downloads/naturemag_200604.pdfHere’s the Cornell page for an over view:
http://www.css.cornell.edu/faculty/lehmann/biochar/Biochar_home.htmUniversity of Beyreuth TP Program, Germany http://terrapreta.bioenergylists.org/?q=taxonomy/term/118
This Earth Science Forum thread on these soils contains further links, and has been viewed by 100,000 self-selected folks. ( I post everything I find on Amazon Dark Soils, ADS here):
http://forums.hypography.com/earth-science/3451-terra-preta.htmlThere is an ecology going on in these soils that is not completely understood, and if replicated and applied at scale would have multiple benefits for farmers and environmentalist.
Terra Preta creates a terrestrial carbon reef at a microscopic level. These nanoscale structures provide safe haven to the microbes and fungus that facilitate fertile soil creation, while sequestering carbon for many hundred if not thousands of years. The combination of these two forms of sequestration would also increase the growth rate and natural sequestration effort of growing plants.
The reason TP has elicited such interest on the Agricultural/horticultural side of it’s benefits is this one static:
One gram of charcoal cooked to 650 C Has a surface area of 400 m2 (for soil microbes & fungus to live on), now for conversion fun:
One ton of charcoal has a surface area of 400,000 Acres!! which is equal to 625 square miles!! Rockingham Co. VA. , where I live, is only 851 Sq. miles
Now at a middle of the road application rate of 2 lbs/sq ft (which equals 1000 sqft/ton) or 43 tons/acre yields 26,000 Sq miles of surface area per Acre. VA is 39,594 Sq miles.
What this suggest to me is a potential of sequestering virgin forest amounts of carbon just in the soil alone, without counting the forest on top.
To take just one fairly representative example, in the classic Rothampstead experiments in England where arable land was allowed to revert to deciduous temperate woodland, soil organic carbon increased 300-400% from around 20 t/ha to 60-80 t/ha (or about 20-40 tons per acre) in less than a century (Jenkinson & Rayner 1977). The rapidity with which organic carbon can build up in soils is also indicated by examples of buried steppe soils formed during short-lived interstadial phases in Russia and Ukraine. Even though such warm, relatively moist phases usually lasted only a few hundred years, and started out from the skeletal loess desert/semi-desert soils of glacial conditions (with which they are inter-leaved), these buried steppe soils have all the rich organic content of a present-day chernozem soil that has had many thousands of years to build up its carbon (E. Zelikson, Russian Academy of Sciences, pers. comm., May 1994). http://www.esd.ornl.gov/projects/qen/carbon1.html
All the Biochar Companies and equipment manufactures I’ve found:
Carbon Diversion
http://www.carbondiversion.com/Eprida: Sustainable Solutions for Global Concerns
http://www.eprida.com/home/index.php4BEST Pyrolysis, Inc. | Slow Pyrolysis – Biomass – Clean Energy – Renewable Ene
http://www.bestenergies.com/companies/bestpyrolysis.htmlDynamotive Energy Systems | The Evolution of Energy
http://www.dynamotive.com/Ensyn – Environmentally Friendly Energy and Chemicals
http://www.ensyn.com/who/ensyn.htmAgri-Therm, developing bio oils from agricultural waste
http://www.agri-therm.com/Advanced BioRefinery Inc.
http://www.advbiorefineryinc.ca/Technology Review: Turning Slash into Cash
http://www.technologyreview.com/Energy/17298/3R Environmental Technologies Ltd. (Edward Someus)
WEB: http://www.terrenum.net/The company has Swedish origin and developing/designing medium and large scale carbonization units. The company is the licensor and technology provider to NviroClean Tech Ltd British American organization WEB: http://www.nvirocleantech.com and VERTUS Ltd.
http://www.vertustechnologies.com
Genesis Industries, licensee of Eprida technology, provides carbon-negative EPRIDA energy machines at the same cost as going direct to Eprida. Our technical support staff also provide information to obtain the best use of biochar produced by the machine. Recent research has shown that EPRIDA charcoal (biochar) increases plant productivity as it sequesters carbon in soil, thus reducing atmospheric carbon dioxide.http://www.egenindustries.com/
If pre-Columbian Kayopo Indians could produce these soils up to 6 feet deep over 15% of the Amazon basin using “Slash & CHAR” verses “Slash & Burn”, it seems that our energy and agricultural industries could also product them at scale.
Harnessing the work of this vast number of microbes and fungi changes the whole equation of energy return over energy input (EROEI) for food and Bio fuels. I see this as the only sustainable agricultural strategy if we no longer have cheap fossil fuels for fertilizer.
We need this super community of wee beasties to work in concert with us by populating them into their proper Soil horizon Carbon Condos.
Erich J. Knight
Shenandoah Gardens
1047 Dave Berry Rd.
McGaheysville, VA. 22840
(540) 289-9750 -
I would like to mention another sequestration technique that has at least as much potential as Biochar, and is at least discussed on as enthusiastically as biochar, but in other networks, mainly french ones. This method is called Ramial Chipped Wood, and consists out of bringing chipped tree branches on the land. This method has the advantage that during the decomposition into stable humus (30-50% of the original C content, so as efficient as Biochar) minerals, enzymes and sugars are made available for soil life. Biochar mainly hosts life, and much less feeding it. Also RCW is cheaper, because no technology is needed, except a chipper. Finally the layer of chips prevent evaporation and unwanted herbs to grow. Permanent soil cover is also part of what has been called “Conservation Agriculture” (CA). In fact SA was the main method of sequestration paid by voluntary carbon offset funds in the USA and Australia. RCW can be seen an advanced step of CA, sequestering 10 times more than CA, up to 100 tons CO2 per hectare in 10 years time.
See for background info on RCW:
- Ramial Chipped Wood: the Clue to a Sustainable Fertile Soil (2007), by Diane Germain, Ph.D., P. Eng. http://www.hydrogeochem.qc.ca/brf/ramial_chipped_wood_2007_11_27.pdf
- http://www.sbf.ulaval.ca/brf/regenerating_soils_98.html -
Why doesnt the mass farming of hemp (or, gasp…cannabis) ever factor in to discussions on reducing CO2? I find it to be the height of irony that cannabis growers secretly purchase pollutant fertilizers and CO2 production machines to get higher yields at the same time the world is fretting over how we are going to lower CO2 in the atmosphere.
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Excellent article
Regarding comparisons between biochar and ramial chipped wood method – the carbon in chipped wood is not removed from the atmospheric carbon cycle as the carbon is released when chips decompose.
Similar efforts to apply biochar to soils result in effectively permanent sequestration of carbon (many hundreds to thousands of years) and don’t need renewing every few years.
I don’t doubt that ramial wood chips provide many agricultural and environmental benefits, but that the comparison here is not on topic with biochar’s potential to permanently sequester carbon and hence it’s value in a carbon economy.
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I like to make this technic BIOCHAR in DRC but I meet
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