In my last post, I discussed (among other things) the fascinating potential benefits of highly-efficient micro-gasification stoves, and the potential agricultural and climate benefits of using the char they produce as a soil amendment. There seems to be tremendous promise in the basic idea—around the world, 500 million of the world’s poorest people cook on inefficient stoves that burn biomass, usually wood or charcoal, and they often cook on them indoors, which creates horrible indoor-air quality and related health problems. The new stoves are relatively cheap, and they are efficient, burning 40-50% less fuel than a traditional “three rocks and a pot” cooking setup. They can also burn a wide variety of biomass, including agricultural wastes and dung. This could reduce pressure on forests, and could reduce or eliminate traditional charcoal production, which is highly polluting. The stoves also release dramatically fewer harmful particulates and other emissions into the air.
The good news doesn’t seem to stop here—the stoves produce charcoal that can be applied to gardens or agricultural land as “biochar”, which improves water and nutrient retention, improves the workability of soils, and improves yields. AND, the carbon in biochar is in a chemical form that is “recalcitrant”, and therefore stays in the soil for hundreds or thousands of years, which effectively removes it from the carbon cycle, which, if practiced by millions upon millions of people, could reduce atmospheric carbon and help ameliorate global warming.
What’s not to love? But despite the fact that improved, inexpensive cookstoves have been around for decades, and have been supported by groups such as the United Nations, the Global Alliance for Clean Stoves, WorldStove, and the World Health Organization, they haven’t fully caught on in the developing world. The biochar addition to this whole idea is a newer one, and groups that promote it appear to encountering glitches as they try to implement a biochar system, despite its promise. It’s a case, it seems, of things never being quite as simple as they seem at first glance.
This can be seen in an interesting study of the effectiveness of one such program to help poorer families in Cambodia and India adopt both the new stoves and the use of biochar—“Biochar Stoves: An Innovation Studies Perspective“. Written by researchers at the University of Edinburgh, it tracked the use of several different stove designs in a variety of real-world contexts in 2010 and 2011, and studied many aspects of the improved-stove and biochar ideas. As it turns out, in the real world a wide variety of obstacles prevented the stoves from quite fulfilling their potential. The study is over seventy pages long, but here are some of the salient points—
— Not all the stoves make char. Some, like the TLUD (Top-Lit Up-Draft) stoves, make char, but have to be stopped at the right time, or the char combusts completely into ash. To get the char, they either have to be quenched with water or dumped out at the right time in the burning process. Both methods appear to be cumbersome in the real world, as one might imagine. Of all of the stoves, the Anila designs, in which biomass is loaded into an outer ring where it pyrolizes, made the most char. But, the Anila stoves work even if you skip the step of loading the outer ring, and it seems many families did skip this step, probably because they didn’t see the value in burning extra wood just to make char.
— When char was produced, it wasn’t always applied to the soil as biochar. Char (charcoal) is a valuable product in the developing world; something that can be burned or sold. Many families did just that, and burned the char in charcoal stoves, or sold it to others for that purpose. To take something that was worth money and till it into the soil, despite promised benefits, didn’t seem to always catch on. Some argue that this is exactly why we need to put a price on sequestering carbon, to bring market forces to bear on this issue, but others, such as Biofuelwatch, argue that this is exactly the danger we should fear—a world where the burning up of trees becomes profitable. In a world of shrinking forests, I can’t exactly say that I feel that the fears of Biofuelwatch are misplaced. It’s a tricky issue.
— There were cultural obstacles. The new stoves didn’t always fit into the cultural regimes that governed cooking and gender roles. Sometimes this was due to how the fuel was obtained, other times it was something as simple as the height of the stove. For cultures where cooking is done from a squatting position, some of the stoves were just too tall (many designs work better with a short stack on top of them, which increases the chimney effect). This one surprised me, it’s one of those unexpected items one wouldn’t normally anticipate.
— The “energy ladder” often means that the whole idea of a biomass stove that produces char has limited appeal. This one also surprised me, but made perfect sense once I thought about it. Here’s a chart from the World Health Organization—
The bottom line here is that what many of the families REALLY wanted was a propane or natural gas stove. And once families have them, they have no real desire to “revert” to a stove that burns biomass, even if the biomass stoves were cheaper or could produce other benefits.
— The biochar stoves were often harder to cook on. Though the stoves may be more efficient than other improved stoves (like rocket-stoves), they are fueled in batches, at the beginning of a cooking cycle, which makes them more difficult to use. In addition, the study found that it is difficult to increase or decrease the heat on most of the biochar stove designs, which is something a rocket stove can do well.
— The use of biochar was effective as a soil amendment, but not overwhelmingly so. The explanation for this doesn’t seem to be in this particular study, but from what I’ve read elsewhere, biochar needs to be “loaded up” with nutrients before it is applied to fields, because it is so absorptive that it actually will capture nutrients from the soil if applied directly to the soil in quantity. This biochar preparation can be done, for example, by adding the char to organic materials as they compost, and then adding the compost to agricultural soils. The study found improved yields from the methods that were employed, but not in all cases, and they conclude that more study needs to be done.
All of this is a bit sobering, and might be a reminder that just because something sounds like a good idea, that it doesn’t mean that it’s workable. There are still plenty of solutions to all of these stove-related problems, such as the pelletization of grass crops for fuel, or improved stove designs, or more education and research about the benefits of biochar. But what I really wonder is whether the whole effort is a Band-aid, when we might be needing a tourniquet. The average poor person in the developing world has something like 1/20th of the climate impact of someone in the United States or the industrialized world (good Tom Murphy post, “The Real Population Problem“). Americans and other citizens of the wealthy world can (and do) choose to eat lots of meat, drive big vehicles, power up their hot-tubs, and run their air conditioners, and the consequences of these actions dwarf those of the world’s poor trying to cook a meal.
It seems we have met the enemy, and he is us.