I am on the board of the U.S. Biochar Initiative and author of <i>The Biochar Solution: Carbon Farming and Climate Change</i> (2009) and <i>BURN: Using Fire to Ignite a New Carbon Economy to End the Climate Crisis</i> (2018). In a collaborative spirit let me offer a few corrections to errors in your post.
“Biochar sometimes referred to as charcoal”
Biochar is never referred to as charcoal. Charcoal has little quality control, is burned, and returns its carbon to the atmosphere. It is often tainted with additives unsuited to farming and gardening.
“This type of sequestration is sometimes called pyrogenic carbon capture and storage, or bio-energy carbon capture and storage, with the latter being more commonly used.”
The two processes are distinct. BECCS may or may not produce biochar but produces energy as heat and/or electricity. PyCSS produces biochar and bio-oils and may or may not capture heat or co-generate electricity.
"The thermal treatment of biomass at 350 °C–900 °C in an oxygen-deficient atmosphere.”
Below 450°C you will not get torrified biomass not biochar. Temperature matters because that is what releases elemental bonds and changes carbon's molecular form to create the ring and chain structures that do not readily degrade. At 350°C the product you create will not withhold carbon from biological cycling as it remains in a labile form. Above 450° - 600°C (depending on other variables) it may be withheld from the carbon cycle for hundreds to thousands of years. There are documented examples of hundred-million-year-old biochars.
“Three main carbonaceous products are generated during this process, which can be stored subsequently in different ways to produce [negative emissions]: a solid biochar as soil amendment, a pyrolytic liquid (bio-oil) pumped into depleted fossil oil repositories, and permanent-pyrogas (dominated by the combustible gases CO, H2 and CH4) that may be transferred as CO2 to geological storages after combustion.”
You need to separate each product from its potential uses. All have multiple applications, which affect durability, price, and other values. Biochar strengthens concrete 30%, for instance, and reduces the requirement for sand. It is also valuable in electronics, dyes, batteries, water filtration, mold-control and much more. Soil application may be its lowest value proposition. Likewise it would be a great waste to pump bio-oil or volatile gases into geological storage when those can form industrial cascades as bioplastics, composites, polymers, chemicals and epoxies, and also have soil chemistry applications.
“Deliberate biochar creation has a long history. Humans have been taking advantage of this soil additive for a long time, documented at least 150 years in the western world, and evidence of its use for centuries longer in Africa and Asia."
Anthropogenic dark earths widely found in South America have been dated back 8000 years. There is no continent except Antarctica where ancient, biochar-infused soils have not been discovered.
Durability is a function of kiln temperature; pyrolysis dwell time; and end application—in other words, it is susceptible to quality control, and that is coming to be regulated by the drawdown credit marketplace and ESG demands by buyers.
“The potential for biochar as a climate change mitigation tool is substantial, although mixed in magnitudes. Current variations in contributions of carbon sequestration lie between 1 to 35 GT CO2 per year. Still, due to uncertainties in the availability of biomass for pyrolysis and the yet to be demonstrated scale of projects, it could be anywhere from 0.3-2 GT CO2 per year.”
When all the potential uses for biochar at a profit are taken into account (ignoring carbon offset subsidies), its limiting factor is only the availability of photosynthetic-origin feedstocks. As Kathleen Draper and I describe in detail in <i>BURN,</i> if you factor in future marine algae farming and kelp forestry wastes, municipal sewage and rubbish, wildfire mitigation, and step-harvested agroforestry, the potential for <i>annual</i> sequestration for biochar is likely to be well above 50 GT CO2.
Thank you for your consideration of this important topic.
Albert Bates
Global Village Institute for Appropriate Technology
Sir:
I am on the board of the U.S. Biochar Initiative and author of <i>The Biochar Solution: Carbon Farming and Climate Change</i> (2009) and <i>BURN: Using Fire to Ignite a New Carbon Economy to End the Climate Crisis</i> (2018). In a collaborative spirit let me offer a few corrections to errors in your post.
“Biochar sometimes referred to as charcoal”
Biochar is never referred to as charcoal. Charcoal has little quality control, is burned, and returns its carbon to the atmosphere. It is often tainted with additives unsuited to farming and gardening.
“This type of sequestration is sometimes called pyrogenic carbon capture and storage, or bio-energy carbon capture and storage, with the latter being more commonly used.”
The two processes are distinct. BECCS may or may not produce biochar but produces energy as heat and/or electricity. PyCSS produces biochar and bio-oils and may or may not capture heat or co-generate electricity.
"The thermal treatment of biomass at 350 °C–900 °C in an oxygen-deficient atmosphere.”
Below 450°C you will not get torrified biomass not biochar. Temperature matters because that is what releases elemental bonds and changes carbon's molecular form to create the ring and chain structures that do not readily degrade. At 350°C the product you create will not withhold carbon from biological cycling as it remains in a labile form. Above 450° - 600°C (depending on other variables) it may be withheld from the carbon cycle for hundreds to thousands of years. There are documented examples of hundred-million-year-old biochars.
“Three main carbonaceous products are generated during this process, which can be stored subsequently in different ways to produce [negative emissions]: a solid biochar as soil amendment, a pyrolytic liquid (bio-oil) pumped into depleted fossil oil repositories, and permanent-pyrogas (dominated by the combustible gases CO, H2 and CH4) that may be transferred as CO2 to geological storages after combustion.”
You need to separate each product from its potential uses. All have multiple applications, which affect durability, price, and other values. Biochar strengthens concrete 30%, for instance, and reduces the requirement for sand. It is also valuable in electronics, dyes, batteries, water filtration, mold-control and much more. Soil application may be its lowest value proposition. Likewise it would be a great waste to pump bio-oil or volatile gases into geological storage when those can form industrial cascades as bioplastics, composites, polymers, chemicals and epoxies, and also have soil chemistry applications.
“Deliberate biochar creation has a long history. Humans have been taking advantage of this soil additive for a long time, documented at least 150 years in the western world, and evidence of its use for centuries longer in Africa and Asia."
Anthropogenic dark earths widely found in South America have been dated back 8000 years. There is no continent except Antarctica where ancient, biochar-infused soils have not been discovered.
Durability is a function of kiln temperature; pyrolysis dwell time; and end application—in other words, it is susceptible to quality control, and that is coming to be regulated by the drawdown credit marketplace and ESG demands by buyers.
“The potential for biochar as a climate change mitigation tool is substantial, although mixed in magnitudes. Current variations in contributions of carbon sequestration lie between 1 to 35 GT CO2 per year. Still, due to uncertainties in the availability of biomass for pyrolysis and the yet to be demonstrated scale of projects, it could be anywhere from 0.3-2 GT CO2 per year.”
When all the potential uses for biochar at a profit are taken into account (ignoring carbon offset subsidies), its limiting factor is only the availability of photosynthetic-origin feedstocks. As Kathleen Draper and I describe in detail in <i>BURN,</i> if you factor in future marine algae farming and kelp forestry wastes, municipal sewage and rubbish, wildfire mitigation, and step-harvested agroforestry, the potential for <i>annual</i> sequestration for biochar is likely to be well above 50 GT CO2.
Thank you for your consideration of this important topic.
Albert Bates
Global Village Institute for Appropriate Technology
givx.org