[Stoves] Inherent emissions differ from combustion emissions — by Crispin PP

Dear Karin, Verena and All

I appreciate the explanations.

I have just emerged from the Black Carbon Summit organised by the Polish Government, ICCI, CCAC and the GACC in Warsaw. One of the major outcomes was a clear picture of the change that, while mostly in the mind, has its roots in the performance of advanced stoves: there is a decoupling of emissions from fuel type.

Fuels have chemistry, and stoves have  combustion efficiencies. The former leads to ‘inherent emissions’ and the latter leads to ‘combustion emissions’. Black Carbon is not an inherent emission.

The concept of a ‘clean fuel’ is, without doubt, rooted in the assumption that combustion emissions are in fact inherent emissions. This is a conceptual error.

There was a presentation on advances in coal combustion (it was a conference on small coal and wood fire heating stoves) using state of the art in Poland. The emissions of PM2.5 (which are combustion emissions and the lofting of particles of fly ash) were reduced to 4-5 mg per cu metre (O₂ normalised to 6%) by the combination of their fifth tier boilers and the addition of a 1 kW electrostatic precipitator.

Testing at the China Agriculture University by Altanzul has shown that the TJ4.0 stove (which is two models behind the current one) has emissions in approximately that same range. This was achieved without electric controls, fans or stack cleaning. In short, there is no meaningful relationship between the fuel type (wood, as demonstrated by the Austrians and by the Masonry Heaters in the US or coal as demonstrated in Kyrgyzstan and Tajikistan this winter) and PM emissions. In the case of the Austrian and Americans, the standard (20mg) was met without electronic controls or stack cleaning.

Thus the concept incorporated in the thesis of the paper of ‘people moving to clean fuels’ is mistaken. They already use ‘fuels’ which if burned properly, produce very clean results, as much as 75% below the highest EU standard for air quality.

I agree that there is a war on solid fuels but as we heard in Warsaw, this is not limited to solid fuels only. For about 18 years now there has also been a war on paraffin (kerosene) waged on the basis that ‘it is burned badly in lighting appliances in India’ as if that somehow defined properties of the fuel.

Believe me, kerosene is still on the hit list of the WHO. It is classified as a ‘dirty fuel’ in spite of being the most widely used energy carrier for modern aviation. Ultra-low emissions kerosene appliances like aircraft, FLOX burners and stoves are ignored while 19^th century wick lamps are held up not to illuminate the subject, but to cloud the issue.

I realise it is very fashionable in some circles to promote subsidised LPG. It would be far more effective far sooner and far cheaper in the long run to promote cleaning burning appliances than to subsidise LPG for the next few decades through its expensive, regulation-ensconced and inevitably long supply chain.

If we want transformation at scale, it is far easier to move a stove for a day than fuel for a lifetime.

Crispin

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