[Stoves] ETHOS 2013: Where is the New Data on Stove

Wed Nov 28 22:50:54 CST 2012

Dear Ron

The two messages seem to have crossed in the post but I will try to catch up.

>Forget everything about joules as the fundamental variable.  

My second response did not include Joules. Just Carbon and how to make a CO2 production comparison.

>…do appropriate computations where the fundamental variable is kgs of C or CO2.  Think about comparing the carbon neutrality and carbon negativity values of stoves.

The carbon neutrality of the source is judged on 2 counts by the UNFCCC, meaning there is non-renewable use of biomass and renewable. As I understand their present formulas (they allow mixing of the two) you will have to include the concept and consider coal to be in the same non-renewable category.

So if I get you right you want to consider first the renewable or non-renewable aspect, right? That is not an attribute of the stove but it is an attribute of a programme with stoves in it, or could be.

Next you want to consider the turning of a renewably sourced biomass converted into a sequestered carbon, right?

A non-renewably sourced biomass turned into sequestered carbon would cancel, are we agreed? Because it is unsustainably removed then put back. Is your point also that in doing so, we can get the H2 energy out? If so, then something that was about 50% not-sustainable could be changed into equally-sustainable, right? And I mean in terms of Carbon only, right?

What it boils down to is that you could grow biomass using carbon that was not only recycled into new biomass after taking out some of the energy, but there would be a net sequestration. Is this the idea?

The stove would be part of that equation though it is not a contribution directly by the stove, it is a contribution or achievement of the programme that manages the char and the biomass. For that reason I can’t see how you would attach the sequestration to the stove. If it an attribute of the system of which the stove is an integral part. But without the programme, the stove would not achieve it.

  RWL:  I am certainly claiming that a stove with favorable carbon negative attributes needs to be recognized by stove performance monitoring groups.  

So my point is that the stove is not itself carbon negative. It is the behaviour of people who use it, or a programme that uses it. And that programme would qualify as the creator of that sequestration, not the stove. It is not a feature, metric of attribute of the stove.

>I do happen to believe that many char-making stoves are more energy efficient (because they can easily control power level and excess air) 

I expect them to be and have been disappointed lately as people copy one product or another and don’t get the basics right. I see a digression of opinion from forestry people and stove carbon people coming. The forestry people want to know how much raw fuel a stove takes from the stock of trees and they view ‘efficiency’ as the work done and the amount of wood taken.  So ‘efficient’ has two quite different meanings. I think the heat transfer efficiency of gasifiers should or could be great but I approach things from an engineering perspective – efficiency of mass transfer! No so the boys with the seedlings.

>>Totally agree. There is to be [NO] double-counting.

   RWL. I don't understand last sentence.

Because I left out a word.  J  I meant that, as you said, you can’t claim both to be using less fuel while simultaneously creating masses of char, when that ‘less fuel’ is a number calculated from the energy used, not the fuel used. A stove can’t use ½ the fuel AND yield ½ of the energy in the form of char AND cook a meal with ‘the other ½’. That is three halves.

Regards

Crispin

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.bioenergylists.org/pipermail/stoves_lists.bioenergylists.org/attachments/20121128/4754c62c/attachment.html>