New Generation Wood Stove Evaluation in Dabaab Kenya: Review Series
I just read a very fascinating report called Evaluation of Manufactured Wood-Burning Stoves in Dabaab Refugee Camps Kenya by the Berkeley Air Monitoring Group. This report compares the performance of many of the stoves that were mentioned in a previous post on next generation stoves. As part of this blog, from time to time I will provide a brief review of interesting studies or conferences. This is not meant to be a peer review, but rather the remarks will be my own personal views. Others can express their opinions by commenting on these review postings.
This study reminded me that measuring the efficiency of improved stoves is not a simple task, but it is quite necessary. Often there are evaluations of single stove interventions, but comparative reviews are not as common. Testing methods actually have been a point of great contention and debate because some favor certain types of stoves over others. Such a lack of objective information or comparative testing results has been hampering improved stoves in developing countries for many years. Millions of dollars are given for stove programs and the monitoring and evaluation is often not very credible.
This study actually lays out its methods very clearly describing the testing environment in detail. There also were focus discussion groups with the cooks, a research technique that is highly recommended and often lacking in other work on stoves. The technical part of the study evaluates multiple manufactured stoves using a method called the controlled cooking test. Under this test the same amount of typical local food is cooked with measured amounts of fuelwood. The results are reported in kilograms of the fuelwood required for standardized cooking of one kilogram of food. Again, this is obviously a contrived environment, but it is a standard method that has been used for more than 25 years.
See more below.
Of course there are drawbacks to this study as well. The stoves were tested among a limited number of cooks and under controlled rather than real world conditions. The setting was refugee camps in Africa so there was no stove testing done in actual homes. Instead the cooks were given specific cooking tasks and carried out their cooking in partially covered space. The stoves also are new so there is no long term evidence from which to draw conclusions. How would they perform after a year, two years or five years? These were not stoves purchased by the cooks. Finally, there were no measurements or comparisons of air pollution levels emitted by the different stoves.
Turning to the results, among all the stoves in the study there were no differences in cooking time. This is actually not too surprising since the heat in the pot probably determines the time required to achieve similar cooking tasks. There were differences found in the efficiency of the stoves. All these manufactured stoves performed quite well compared to the open fire. The best performing stove was the Save80 stove which used two-thirds less fuel than the open fire. The stoves from Envirofit and Stovetec involeved fuel savings of about 50 percent compared to an open fire. This would also mean a 50 percent or more reduction in the burden of fuel collection for family members if the study results were mirrored in actual household conditions.
The focus discussion groups revealed that neither the fastest nor the most efficient stove was preferred by the consumers, which emphasizes that there is more to stove marketing than test results. In fact one suggestion by the cooks for all the stoves was that they would like a better view of the fire. The cooks also did not like using the small pieces of wood fed into small openings required for the Save80 and Philips stoves. Also, these stoves all carry price tags that may or may not be affordable to people using the open fire. The price of the stoves was not part the stove testing for obvious reasons.
So what are the results and who is the winner? Picking one winner is actually somewhat irrelevant because of the tightly controlled conditions. But the loser is clearly the open fire. The choice of stove should actually be determined by the marketplace for stoves, but there is a tremendous need for objective information like that presented in this very interesting study. The winner actually may be all the manufacturers that agreed to these performance tests and the enlightened donors willing to fund such interesting and relevant research.
I wish to thank Dean Still who brought this study to my attention.