August 31, 2016


Biochar is charcoal that is added to soil. It is one of the most potent tools our species currently has to slow climate change. It is made by heating wood in the absence of oxygen.

Biochar Kiln 1.0 – The Micro Kiln

The micro kiln was created as a first step on the journey to large-scale biochar production. It was a proof of concept that was easy to make and easy to test. It was simply a small steel box that was placed inside a woodstove. Small pieces of wood waste were placed inside the box and heated by fire. Pyrolysis gasses can been seen burning in picture #5. The finished biochar is in picture #6.This prototype system worked but took up about 1/3 of the space inside the stove. The volumes of biochar it produced were small.

Biochar Kiln 2.0 – The 50 Gallon Drum Kiln

The next step on NOPRI’s biochar kiln design process was to create a 50 gallon drum version using common materials, easily accessed tools and a modest budget. The goal was to learn to control the consistency of the end product and produce garden-scale quantities of biochar. We went through several batches of experimentation with controllable variables (loading density, feedstock material and size, air flow rate, primary fuel consumption, and flame temperature). The system worked but loading, management and post-processing was too labour intensive for practical regular use. Plus there was no easy way to capture and utilize the surplus waste heat coming off of the kiln.

Biochar Kiln 3.0 – The Woodstove Kiln – COMING SOON


The goals for Kiln 3.0 are to create a system that is easy to load/unload, easy to control burn temperature and easy to utilize the waste heat for heating hot water and to produce garden-scale quantities of biochar. Kiln 3.0. will utilize an existing woodstove, plus the heavy steel cores out of two salvaged hotwater tanks.

You can help! Budget requirements for Kiln 3.0 are approximately $1,000 for tooling, materials, and supplies: