Re: [biochar] Methane from char-makers

FIRST POINT:  I think that these statement that “TLUDs emit substantive amounts of CH4" is fallacious reasoning that is jumping to conclusions.   The evidence I have seen (below) is that forced draft TLUDs don’t emit substantive amounts of CH4, and the conclusion on natural draft TLUDs is made on a single? observation of a old design.

In these Yahoo discussions I have only been able the one paper by Cornelissen  et al. (2016), so my comments follow form that.

I think this paper gives some important of data on CH4 release from Kon.Tiki.  We should take note of these emissions and conduct further studies to corroborate their findings, and extend the range of conditions, such as low or high nitrogen content fuels (e.g., manures and leafy biomass).

On the subject of TLUDs, Cornelissen’s paper cites an old study McCarthy et al. (2008) were substantive emissions of CH4 were measured from an early design of natural draft TLUD (ND-TLUD), and low CH4 emissions from a forced draft Philips TLUD (FD-TLUD).  The ND-TLUD in McCarthy paper had at best a Tier-3 burner, and possibly only Tier-2 in emissions.

McCarthy et al’s paper is an important step in SCIENTIFIC reasoning, because it logically REFUTES the hypothesis that "all ND-TLUDs emit benign amounts of CH4"    It also CORROBORATES (but does not logically confirm) the hypothesis that "all FD-TLUDs emit benign amounts of CH4"

However, from McCarthy’s study we can only draw the conclusion that "there exists at least one ND-TLUD such that it emits substantive amounts CH4".    

It would be a logical fallacy called “affirming the consequent” to conclude that “all ND-TLUDs emit substantive amounts of CH4" This is tantamount to declaring “all swans are white” on the basis of seeing some white swans, but bothering to see if there any swans of a different color, i.e. back ones.

What McCarthy’s paper does, however, is challenges us to refute this hypothesis, that “all ND-TLUDs emit substantive amounts of CH4".

Since 2008, there has been work to move ND-TLUDs into the Tier-4 category of emissions.  With these modern ND-TLUDs it is quite likely that the hypothesis that “all ND-TLUDs emit substantive amounts of CH4" would be REFUTED.

From what I can see, this recent Yahoo debate that asserts that “all ND-TLUDs emit substantive amounts of CH4," is fallacious reasoning.    Extrapolating beyond the evidence.  Jumping to conclusions.

I need to be strong on this point, there are damaging consequence to promoting false conclusions.  It has to be emphasized that we need more research first.

SECOND POINT.

When it comes to calculating the contribution of biochar production to the mitigation of climate change, context is really important.

ND-TLUDs are being introduced to get households who are ALREADY burning biomass and producing CH4 to switch to method that makes biochar.  In that context, the biochar should get full credit for sequestering carbon.

That is a different context from where people, who were not previously burning biomass, start making biochar in TLUDs and Kon Tiki kilns.

THIRD POINT

There is a social dimension to ND-TLUD stove.  Households that use a traditional stove are completely self-sufficient in cooking.  When they switch to any ‘improved’ stove that is manufactured elsewhere, they are relinquishing that self-sufficiently.  That is extremely important for communities that are not strongly integrated into a cash economy, living in countries whose currencies have a weak purchasing power in international markets.

The ND-TLUD has a unique feature compared to other biomass stoves.  It automatically makes biochar whilst cooking with less fuel, and greatly reducing women’s exposure to smoke.  Biochar has a value to the household to increase their food production, or can be sold in the community.  Biochar compensates the family for giving up their traditional stove — their self-sufficiency in cooking — by increasing household income and food security.

Because of the interaction of the TLUD and the biochar, this system is socially and economically sustainable, and doesn’t need subsidies for carbon credits to exist (although carbon credits would greatly help in scaling-up and research and development).

For an example, see this video documentary from Bangladesh.  “Documentary — Biochar Production in Bangladesh — The Akha Gasifier Stove (Subtitles)”
https://youtu.be/ujqza-NDy4I
Note that this is at early stages, so don’t take the TLUD design, or how they handle biochar as optimized.  This is a work in progress, and they are learning.

(Disclaimer: All my work on TLUDs and biochar is pro bono)  

Julien.