- Biochar is the ultimate soil repair kit
- Why does biochar have such a powerful effect?
- Biochar sucks CO2 out of the air and locks it in the soil
- Both centralised and mobile schemes will make sense in different regions
- George Monbiot’s unreasonable attack
1. Biochar — the ultimate soil repair kit
The now famous system called biochar cooks up agricultural waste like corn stalks, wheat stems or rice husks and cooks it in a low oxygen process called Pyrolysis. This produces syngas and charcoal. The charcoal is returned to the soil where it becomes a habitat for all sorts of micro-organisms and fungi. The fungi grows in all the nooks and crannies of the charcoal, sucking Nitrogen and more CO2 out of the air as it grows through the soil, adding organic mass. This partially fertilises the soil, reducing the fertiliser requirements of agriculture.
At BestEnergies half of the syngas is then used to cook the next load of Biomass into Biochar, and the other half can be used as gas on the farm. Rob from Transition Culture attended a lecture with the following summary ratio of Biochar products.
“…The machine they have developed for doing the charcoal burning basically takes 10 tons of any woody or plant biomass and turns it into 1 ton of charcoal and 3.2 tons of diesel.”
Check out this must read article by Big Gav at Terra Preta: Biochar and the MEGO effect | Energy Bulletin. Note that I do not regard biochar as solving our liquid fuel energy needs, but it might just provide some niche fuels for the farming sector.
2. Why does biochar have such a powerful effect?
Biochar locks away carbon and rejuvenate the soil, becoming a ‘coral reef’ of the soil that micro-organisms can flourish in. Biochar reduces fertiliser inputs, it does not eliminate them. However by making fertliser and water uptake so much more efficient, it increases crop yeilds and on-site economics for the farmer.
Wae Nelson at TEDx 2012, Orlando, explains that biochar is so porous that one gram of biochar would have the surface area of 3 football fields, and this porous surface has a positive electric charge that sucks nutrients into the biochar which traps them in the soil and prevents them being washed away by rainwater into our rivers. This video has some spectacular photos of the difference biochar can make!
Here’s another TED talk on Biochar, where we learn that if normal agriwaste is composted, it will eventually lose 90% of the carbon to the atmosphere, storing only 10% of the carbon for any length of time. But biochar stores 50% of the carbon in the agriwaste for centuries through to millennia, and becomes one of more most economically effective way to store CO2 in our soils!
And another
As Keplie Wilson of Truthout.org puts it…
“Field trials and experiments in pots show impressive yield gains in charcoal-amended soils, but so far researchers don’t completely understand why. One question is whether the effect is primarily chemical and physical or primarily biological. Charcoal is a highly porous material that is very good at holding nutrients like nitrogen and phosphorus and making them available to plant roots. It also aerates soil and helps it retain water. Charcoal’s pores also make excellent habitat for a variety of soil microorganisms and fungi. Think of a coral reef that provides structure and habitat for a bewildering variety of marine species. Charcoal is like a reef on a micro-scale.
One of the research papers presented at the conference documented an increased diversity of beneficial microbes in terra preta soils as compared with unamended soils, but there are still no answers about whether the fertility increase is due to physical or biological factors. The best answer may be that it is both.”
Not only that, but it retains other NPK nutrients as well.
“Lehmann explains that nutrients from plant and animal remains—like nitrogen, phosphate, and potassium—bind to charcoal or biochar, drastically reducing how much is washed away by the constant rains. It is a gradual process that begins with the charcoal breaking down in the soil over time. Tiny pores in the charcoal, along with changes in its chemistry, provide more surfaces for nutrients to adhere to, which in turn encourages microorganisms to colonize the soil. “With a handful of biochar you can keep many more nutrients in the soil than with a handful of mulch or compost. It is like mopping up nutrients with a magnet that looks like a sponge—that is, it has high surface area like a sponge but can attract a thin layer of material like a magnet,” Lehmann says.”
Discover Magazine
3. Biochar sucks CO2 out of the air and locks it in the soil
With so many positive side effects for soil quality, food quantity, and even a little syngas fuel thrown in for good measure, this is one of the few economic ways to remove CO2 from the air. (Regreening the deserts is another). An International Biochar Initiative PDF states:
“2. What is IBI’s goal for carbon removal from the atmosphere?
IBI is focusing presently on the feasibility of one “wedge,” which equals one gigaton of carbon per year. The term “wedge” comes from an often-quoted analysis (Pacala and Socolow, 2004) showing a need to have seven gigatons of carbon per year (seven wedges) of reduced carbon emissions by 2054 to keep emissions at the 2004 level.3. Is a one gigaton per year biochar wedge achievable by 2054?
Yes. In the four basic scenarios we have examined, we found several ways to create at least one wedge by 2054.”
Even Tim Flannery, author of “The Weather Makers” and 2007 Australian of the Year, has stated to Podcast “Beyond Zero Emissions” that permanently sequestering “6 gigaton per annum … is eminently feasible”.
(About 9 minutes into 24 minute podcast).
The ABC’s Catalyst covered it (calling it Agrichar in 2007) and explained the basics.
Narration: Johannes Lehmann studies how terra preta can store twice as much carbon as other soils, even after thousands of years.
Dr Johannes Lehmann: The evidence is there and that’s what drives us.
Narration: Along with bits of pottery, the ancient soil is mixed with charcoal. What makes the charcoal different from your BBQ is that it comes from wood burned in ovens with out much oxygen. A process known as pyrolysis.
Johannes Lehmann: So this char, organic matter, in this terra preta is much more efficient in doing what we want all soils to do, to retain nutrients for plants, to reduce the losses of nutrients, to reduce the CO2 that goes out of the soil, to enhance soil productivity, and store more carbon.
They also showed that it reduces nitrous oxide emissions from fields, and that is significant because nitrous oxide is a super-greenhouse gas 310 times more powerful than CO2! You can watch the ABC’s Catalyst cover Agrichar here.
4. Both centralised and mobile systems
Centralised
Given that we can produce all the high ERoEI cheap electricity we need to cook up a variety of alternative fuels, I’m not some doomer peak oiler wondering how we’re going to generate enough energy to move the biomass to the biochar plant. Doomers worry that there simply will not be enough energy to do all this, let alone economic concerns. (I have clearly stated my reasons to dismiss this fatalistic worldview in the links above). But let us recap that:
“…The machine they have developed for doing the charcoal burning basically takes 10 tons of any woody or plant biomass and turns it into 1 ton of charcoal and 3.2 tons of diesel.”
In other words, an enormous road train — lets say this one carries 100 tons — goes collecting agriwaste from a variety of farms. Maybe it weighs each pickup and offers the farmer a price, or even a future discount on the biochar and diesel? It depends on the local economy and setup. Anyway, our 100 ton truck dumps it all a central biochar plant, refuels on diesel the plant itself is refining, and drives off to collect more. Meanwhile the power plant cooks up that 100 tons of agriwaste and makes 32 tons of diesel! That’s a great win to the rural economy. A smaller truck can then deliver the highly concentrated 10 tons of biochar back to the farm/s.
Second, given my views on alternative fuels this is not about energy but money: its about the cheapest way to lock up greenhouse gases, fertilise our soils, and help reduce fertiliser requirements on our farms. It’s about replenishing our soils and rural communities. These road trains could go from infamously carrying fossil fuelled diesel to agriwaste and biochar diesel.
Mobile systems:
As the wiki says:
“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. 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 harvests approximately 460 million tons (MT) ofsugarcane annually,[12] with an RPR of 0.30, and a CF of 0.70 for the sugarcane tops, which normally are burned in the field.[13] This translates into approximately 100 MT of residue annually which could be pyrolyzed to create energy and soil additives. Adding in the bagasse (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.[14] Pyrolysis technologies for processing loose and leafy biomass produce both biochar and syngas.[15]“
5. George Monbiot’s unreasonable attack
In March 2009, George Monbiot famously attacked biochar in his article Woodchips with that? He attacked a straw-man, the idea of a biochar enthusiast raving that biochar could save the world and provide all the food and energy we need! I have never claimed that, and a week later George apologised for some of his attack. I don’t think he has really analysed the technology properly, or given it a fair treatment as the important tool it is in our kit against climate change and farmland erosion.
Other references for biochar
ABC’s Catalyst 2007: Reduces nitrous oxide emissions from farming! (Thankfully these emissions are relatively smaller than Co2 because they are hundreds of times more powerful than Co2, and eliminating them is very important. They are caused by over-use of Nitrogen fertilizer, which Biochar helps reduce the use of anyway.)
The Case for burying Charcoal at Technology Review shows that it is cheaper and safer than carbon geo-sequestration or so called “clean coal”.
University of Georgia — Can work with wood chips!
The International Biochar Initiative (IBI)
Eprida — It builds soil organic content with Mychoryzal Fungi as described above
The Biochar wiki is now gaining momentum and scope.
Beyond Zero Emissions — an Australian global warming activist group — have many podcasts on Biochar.
www.carbondiversion.com
Best Energies
Dynamotive
Agritherm
Advanced Biorefinery — Green chemicals
Technology review — Turning Slash into cash
Eclipse Now 