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The Promise of Biochar

Charcoal: The word (for me at least) elicits thoughts of barbeque briquettes or perhaps the favored fuel source for a traditional blacksmith’s forge. It has been in use for thousands of years across the globe and isn’t typically thought of as a particularly “advanced material”. Compared to its allotropic carbon brethren (e.g. nanotubes, graphene, carbyne, activated and nanoporous carbons), charcoal has been the persona non grata. But perhaps we’re about to witness a change from low-value carbon residue to soil amendment and carbon sequestration extraordinaire – the proverbial ugly duckling story, if you will.

Biochar, the name given to charcoal when used for soil improvement and/or geoengineering, is produced through pyrolysis, the thermal decomposition of biomass in the absence of oxygen. Along with solid biochar, the pyrolysis of biomass creates a mixture of liquids (bio-oil) and gases (syngas aka H2 and CO). The ratio of biochar solids compared to gases and liquid is tunable and depends heavily on temperature.

The production and usage of biochar could have a large impact on many of our focal areas here at Pangaea including energy, sustainability, and the environment.

Energy: Pyrolysis is a net energy-producing process typically requiring about 15% of the energy it outputs to sustain itself once initialized. This energy can be used locally or fed in to the grid. The syngas and bio-oil that’s produced can be converted into liquid hydrocarbon fuels using the traditional Fischer-Tropsch process or other newer approaches like using extremophilic microbes and synthetic biology. Furthermore, biochar can directly substitute for coal in many applications as well.

Recently, biochar has made its way in to the energy storage realm. Supercapacitor electrodes have been fabricated using biochar and these devices show similar performance metrics compared to activated carbon electrodes. These devices take advantage of the intricate pore structure that occurs naturally within the biochar. This removes the need for the often costly and not-so-environmentally friendly procedures necessary to impart the desired micro- and nanostructures necessary to increase electrode surface area and device performance.

Sustainable Chemical Production: Bio-oil can be refined to create high value chemicals along with pesticides and food additives. Beyond biofuels (liquid hydrocarbons), the syngas can be used to produce methanol and hydrogen.

Environment: Biochar can be used to enhance the properties of native soils while simultaneously sequestering carbon from the atmosphere. From improved water retention to reduced soil emissions and nutrient leaching, biochar as a soil amendment has been shown to increase agricultural yields and restore marginal lands.

The ability of biochar to retain important nutrients including phosphorus and nitrates potentially can reduce fertilizer requirements limiting harmful runoff and algal blooms. Therefore, biochar products can potentially be utilized in horticulture applications such as potting mixes, organic fertilizers, and peat replacement.

Long-term sequestration of carbon is achieved when biochar is ploughed in to soils storing greenhouse gases in the earth instead of the atmosphere. Combined with net positive energy production displacing fossil fuel generation and increased agricultural productivity, biochar could really be a big win for both farmers and the environment.

Materials that have the ability to make big impacts across multiple big markets excite us here at Pangaea and can lead to excellent venture returns. Maintaining focus is key in wading one’s way through many of these nascent markets, sometimes simultaneously. As a VC firm supporting advanced materials entrepreneurs, we believe our experience in the space and world-leading partner network can help move the needle for our portfolio companies as they trudge toward commercial success. While the challenges loom large, biochar could represent a sustainable pathway towards improved agriculture and gigaton-level carbon mitigation.

Associate, Pangaea Ventures Ltd. Matt holds an MPhil in Micro- & Nanotechnology Enterprise from the University of Cambridge and graduated summa cum laude from the University of Pennsylvania with a BSE in Materials Science & Engineering.View Matthew Cohen's profile on LinkedIn

Comments

  • Guest
    Tony Pietsch Monday, 25 November 2013

    Hello Matthew,

    With regard to Biochar, I thought that you might enjoy some additional history. There are many scholarly (and not so) articles that address soil enhancement through blending in bio-derived charcoal and its potential benefits such as: "The Charcoal Vision: A Win–Win–Win Scenario for Simultaneously Producing Bioenergy, Permanently Sequestering Carbon, while Improving Soil and Water Quality".

    Perform a search for "charcoal soil enhancement" and you'll find a wide variety (from individual speculation to USDA advocacy) of information. The reality is that this is neither new nor speculative -- I believe that the Discovery channel had a special dedicated to biochar based on historical evidence in the Amazon River region, and included its continued application in the upper watershed in Peru (it has been made this way in the Amazon for over a thousand years). The charcoal is ground into small flakes and mixed with poor soil in about a 1:10 ratio. It is often referred to as "black soil" and old deposits are being "mined" today in Brazil to become short-lived soil enhancement for high-intensity agriculture that uses its fantastic properties up, leading to another round of enrichment and total consumption. The biological properties come about from the very high surface area of porous carbon that enables it to retain minerals, water, etc. that would otherwise be washed away during flooding in the region.

    My belief is that soil enhancement with bio-charcoal to a depth of 6 feet or more, restoration of lower density agriculture or wild plant life with recycling into biochar is the ONLY sustainable means of reducing atmospheric CO2. Plants have evolved to be able to convert very low concentrations (currently about 400 ppm) back down to the low double digit values found in the past. Sadly, we're still turning this wonderful blue planet into a desert.

  • Matthew Cohen
    Matthew Cohen Monday, 02 December 2013

    Hi Tony,

    Thanks for the additional info. In the case of biochar, looking to our past can really help propel us towards a better future.

  • Guest
    Neil Farbstein Monday, 25 November 2013

    The problem with biochar as greenhouse mitigation agent is that it is black and absorbs sunlight. When biochar in soil get blown by then wind it gets into the atmosphere and heats the atmosphere not cooling it as its adherents say. Instead of burying it in the soil. We can fertilize aquaculture lagoons with it.

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Guest Tuesday, 16 September 2014