The aim of this study was to perform a rigorous field evaluation of alternative cooking fuel during actual use. Chabon Vet (green charcoal) fuel briquettes are produced by Carbon Roots International (CRI) in Cap Haïtien, Haiti and are made from carbonized agricultural waste, predominantly sugarcane bagasse. During this study Chabon Vet was compared to other commonly used wood-derived fuels (wood charcoal and firewood). 93% of Haitians rely on wood and wood charcoal as their primary household energy source. This has resulted in mass deforestation leaving only 2% of Haiti’s original forest cover remaining. In addition, Haitians spend, on average, 50% of their income on cooking fuel. CRI is addressing these urgent issues by introducing a renewable alternative to wood fuels made from readily available agricultural waste.
A mobile laboratory was developed and deployed by a team from MIT’s D-Lab to perform cooking technology evaluations in and around Cap-Haïtien where Chabon Vet is produced and sold. A modified version of the standard laboratory test method for cooking technology, the Water Boil Test (WBT), was used during the evaluations. The field team set up the mobile lab at a different household each day and worked with stove users to perform the tests. This method is unique in that it utilizes the advanced measurement methods commonly used in controlled laboratory testing, but brings the laboratory to the home and involves the user to incorporate local practice and behavior into the test.
A total of 57 individual WBTs were performed in seven different households and one commercial setting (restaurant). Of the 57 WBTs performed, 44 were completed successfully. Three different fuels (Chabon Vet, wood charcoal and firewood) and eight different cookstoves were tested.
The averaged test outputs from this study show that in general Chabon Vet performs similarly to conventional wood charcoal in terms of practical use, efficiency (Figure 1) and emissions indicators (Figure 2). Use of Chabon Vet in both traditional and improved stoves requires more time to complete the WBT compared to wood charcoal due in large part to its lower net calorific value (also referred to as lower heating value). At the same time, the average burn rate and firepower of stoves using Chabon Vet are 30-45% lower than stoves using wood charcoal, which results in more efficient heat transfer from the burning fuel to the pot (thermal efficiency). The average dry fuel consumed during the WBT was nearly equal for Chabon Vet and wood charcoal despite the large difference in calorific value.
Measurement of respirable particulate (PM10) and primary gas phase emissions (carbon dioxide, carbon monoxide, sulfur dioxide, nitrogen oxides) were obtained during each test in this campaign. These results reaffirm previous findings which show that the use of carbonized fuels produce significantly lower PM10 emissions than firewood, achieving 2-3 orders of magnitude reduction. Emissions factors of CO2 from use of Chabon Vet are on average 29% lower than wood charcoal. Emissions of CO for both Chabon Vet and wood charcoal are higher than for firewood used in a three-stone fire.
