Ron Larson sent me an interesting link: http://www.vrac.iastate.edu/ethos/files/ethos2012/SatAM/Panel/Mitchell_IWA:ISO.pdf
In this presentation, please see page 3 where mention is made of the Multiple Health and *Broader Impacts* of Household Energy. Note that there is a block diagram on the Environment. A distinction is made between local and global. Under local, mention is made of deforestation, erosion and desertification, and under global, mention is made of black carbon and *other greenhouse gas emissions*. No doubt CO2 is considered a greenhouse gas by the author of this presentation. On page 13, of the Lima Consensus, mention is made of tier 3 stoves that stretch goals which achieve significant, measurable health *and/or environmental goals*. On page 15, under Climate Impact the question is posed: what affect will the stove have on local and *global environment*? On page 16, mention is made of Tier 4 stoves that target ambitious health and *environmental* outcomes. A stove should be rated on what it is designed to burn. If a stove does not burn biochar, biochar should be left out of the equation used in determining its efficiency. Biochar is not part of the fuel that powers biochar-making stoves, and the production of biochar is not a residue left behind that has a negative environmental impact. The fuel that powers a biochar-making stoves is the syngas that it produces. Syngas is the fuel - not biomass. The same logic applies to some fossil fuel gas stoves. In many cases we do not judge their efficiency starting from the chemical composition of the fuel that came out of the ground. Before some fossil fuels can be used as a fuel, they have to be refined and cracked, and all of this processing translates into an inefficiency that has to be taken into account as gas is burned in a kitchen. The refining and cracking of many fossil fuel gases takes place outside of the kitchen. By contrast a biochar-making stove does the refining and cracking and burning of the gas all within the one process - while a meal is being cooked. Unlike some fossil fuel gas stoves where the refining and cracking of the gas take place at a refinery outside the kitchen, the gas that my biochar-making stove produces is not allowed to cool down before it is burned. I measured the temperature of the hot syngas from my stove, and at the beginning of a burn, it reached a temperature greater than 500 C. The efficiency of a gas stove should also be measured in terms of the efficiency of what goes into preparing the gas that it consumes. Note that there are some Chinese low-temperature pyrolysis stoves that, unlike my stove, filter and cool down the gas before it is routed to a burner. The pyrolysis unit is situated outdoors, while the burner is situated in the kitchen. All of this should be taken into account when judging the efficiency of such a stove. In judging the efficiency of a stove, we cannot limit our analysis to only what happens in a kitchen. Biochar is a precious resource that has advantages far beyond the energy it contains. Its contribution to the reduction of greenhouse gas emissions is significant, and yet this is not explicitly taken into consideration in evaluating Tier 4 stoves that target ambitious environmental outcomes. Perhaps something is missing here. Where I live in Vietnam (Dalat), there are thousands of greenhouses within and around the city. The people who operate these greenhouses know why they put rice hull biochar into their potting soil mixes. They do so because biochar increases plant growth and reduces water and fertilizer consumption. All of this should impact ambitious environmental outcomes of Tier 4 stoves. Thanks. Paul Olivier -- Paul A. Olivier PhD 26/5 Phu Dong Thien Vuong Dalat Vietnam Louisiana telephone: 1-337-447-4124 (rings Vietnam) Mobile: 090-694-1573 (in Vietnam) Skype address: Xpolivier http://www.esrla.com/
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