Energetic, economic and social analysis of briquettes made from sawdust of two tropical wood species and their hybrids: Milicia excelsa (Iroko) and Pterocarpus soyauxii (Padouk)

Abstract

The aim of this study was to assess the energy consumption, economic viability and social impact of briquette production using sawdust from two tropical woods. Energy use was determined at each stage of the production process. A 20-year economic analysis was carried out, assessing operating and investment costs using life-cycle costing (LCC). Social impacts were surveyed from 120 households in the city of Douala. The energy analysis shows that carbonization is the most energy-intensive operation, whereas the drying of sawdust is the least energy-intensive operation. The energy consumed in making briquettes is 209.86 kWh, 223.68 kWh, 215.69 kWh, 214.95 kWh and 213.79 kWh respectively for briquettes P (100 % Padouk), I (100 % Iroko), A (75 % Padouk+25 % Iroko), B (25 % Padouk+75 % Iroko), and C (50 % Padouk+50 % Iroko). The energy input per type of briquette is 1273.28 kWh, 1191.97 kWh, 928.68 kWh, 818.4 kWh and 873.54 kWh respectively for P, I, A, B and C. Briquettes are economically viable, with net present values (NPV) of $95,145 for pure and $41,730 for hybrid briquettes. The internal rates of returns (IRR) ranging from 20 % to 34 %. The social analysis shows that the main factors guiding the choice of cooking fuel are cost, household income and cleanliness. Cooking fuel usage in Douala is dominated by charcoal and liquefied petroleum gas. The average household size in Douala is approximately 5.4 people and 84 % of the population is between the ages of 18 and 60. Households rated briquettes as excellent (21 %) and good (54 %) and are willing to adopt briquettes as their main cooking fuel. These results indicate that sawdust briquettes are cost-effective and energy-saving, making them ideal for household cooking. Sawdust briquettes facilitate household access to cooking energy and are suitable as an energy source in Cameroon. • Sawdust is mixed in various proportions and converted into briquettes. • Energy analysis, economic viability and social impact of briquette are investigated. • Energy balance, sensitivity analysis and household surveys have been undertaken. • Briquettes could benefit both producers and consumers like households. • Carbonization is the most energy-intensive stage of the process.