While none of the techniques listed below approach industrial scale, they are illustrative and engaging ways to make small amounts of charcoal for experimentation. In developing world scenarios, biochar will most likely be made in small amounts using simple techniques like these. Over time, vast areas of soil can be regenerated in places of the world where it is needed the most to ensure food security. If you'd like to contribute a design, please email us at info@carbonzero.ch. Thanks!

The CarbonZero team has constructed a simple closed retort kiln using an insulated firebrick enclosure designed for a 200 liter steel barrel as a retort. Further images and explanations are provided here!

Folke Gunther demonstrates how to construct and use a simple biochar kiln made from two metal barrels with ample images and explanations here.

This article by Gary Gilmore contains a wealth of basic information for newcomers to charcoal making, and explains how to construct and use another simple two barrel kiln with a retort and afterburner here.

Making Biochar

Everything Nice is a biochar producing stove design by Nathaniel Mulcahy of World Stove - http://www.worldstove.com. More details are available at http://www.bioenergylists.org/node/2584/ and http://www.bioenergylists.org/en/sheet-steel-EverythingNice-stove.

Peter Hirst demonstrates New England Biochar's adaptation of the barrel in a barrel method. I wonder if his claim that the retort remains around 450 to 500 C is true though, especially if the feedstock is dry. See the video here.

A series of YouTube videos explains a unique horizontal afterburner design to produce biochar, process heat and electricity. TheMadGeneralist

Lucia WorldStove on YouTube

With a "terra preta pot" you can make biochar from crop residues instead of wood, and you can use the pot at the same time to cook food or to warm the home. The pot-in-a-pot is in fact a micro-pyrolyser. It is made from local materials, and can be manufactured by any skilled potter. Thus it is possible to make biochar-generating cooking stoves while maintaining local pottery traditions.

Unfortunately, the website describing the production technique seems to no longer be available, but we leave the link for a while longer. http://terrapretapot.org/

This entertaining series of YouTube videos shows and explains the traditional heap method of charcoal making as practiced in Pennsylvania, USA.