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EAI presents Cleantech Snapshots: a quick summary of some of the most interesting and innovative areas in clean technology that will drive the sustainability movement in future.


This snapshot focuses on Biochar. Within this page you will find


Overview

  • Biochar is charcoal used for soil amendment. Like all other charcoal, it is created by pyrolysis of biomass. It is a solid material obtained from the carbonization of biomass
  • Biochar may be added to soils with the intention to improve soil functions and to reduce emissions from biomass that would otherwise naturally degrade to greenhouse gases
  • It also has appreciable carbon sequestration value which provides significant benefits as a medium for carbon sequestration, while at the same time sustainably enhancing soil fertility
  • It is stable and can endure in soil for thousands of years. Biochar has been used in various forms in many cultures over history, and is making a comeback in its popularity owing to the emphasis on sustainability in agricultural practices

BiocharBiochar Production(Image source)

 

Composition

  • Biochar is produced using pyrolysis – biomass is super-heated in the absence of oxygen at high temperatures (350-700°C) in specially designed furnaces. The most sustainable feedstock are what’s now considered waste: excess manure, wood debris, construction waste, slash from forest thinning, food processing waste, residue from methane digesters or urban tree trimmings
  • In the modern method, hydrocarbons and most of the oxygen and hydrogen in the biomass (including GHGs) are burned and captured. Thesecaptured emissions are known as synthesis gas and can be used like natural gas
  • It stimulates the activity of soil microorganisms, which can greatly affect the microbiological properties of soil. But it’s much too expensive for the farmers to afford, which is the reason for not been widely used by the farmers

Comparison of biochar with synthetic fertilizers

Pros:
  • Both replenishes and retains soil nutrients so crops will be more nutrient-dense
  • Improves cation exchange capacity for greater mineral delivery to plant roots
  • Increases microbial populations, including increased reproduction and higher retention of microorganisms
  • Neutralizes and maintains pH of soil
  • Increases the water holding capacity of soil
  • Improves resistance to infestation by fungus,nematodes and insects
Cons:
  • Feedstock availability is limited
  • Biochar needs to be handled carefully (highly flammable)
  • Biochar System Deployment is difficult

Potential in Future

  • Economically, biochar is influenced by favorable government policies;uncertainties regarding change in policies may risk investment in biochar production. The viability also depends on the growing cost of waste disposal and implementation of renewable energy targets

Biochar Case studies

  • The social shaping of technology –A case study of biochar in Denmark. Link
  • Department of Agriculture, Fisheries and Forestry, Australia’s Farming Future Climate Change Research Program.Link
  • Use of biochar for Soil Health Enhancement and Greenhouse Gas Mitigation in India: Potential and Constraints. Link
  • Biochar Stoves: an innovation studies perspective. Link