Comparative analysis of wood fuel energy use in tea processing factories in Rwanda

Tea processing in key producing countries such as Kenya, Sri Lanka, and Rwanda remains heavily reliant on wood fuel, particularly for withering and drying stages. Wood fuel poses significant sustainability challenges despite its widespread use, including deforestation, low energy efficiency, and rising production costs. In Rwanda, where tea is a major export commodity, the inefficient use of wood fuel in processing factories presents both environmental and economic concerns. This study provides a comparative assessment of wood fuel consumption in three anonymized tea factories designated as Factory A, Factory B, and Factory C located across different regions of Rwanda. Ethical protocols were followed, with factory identities withheld and informed consent obtained. April 2024 and August 2024 were selected as representative months for the rainy and dry seasons, respectively. Primary data on wood usage and made tea output were collected, and energy efficiency was calculated in kilograms of made tea per cubic meter of firewood consumed. Fuel costs were standardized using a rate of 28,000 Rwandan Francs (RWF) per sterre (1 m³), as informed by national benchmarks. Results revealed marked disparities in wood fuel efficiency across factories and seasons. Factory A demonstrated the most significant seasonal improvement, reducing wood consumption from 1.63 kg per kilogram of made tea in April to 1.17 kg in August—equating to an increase in fuel efficiency from 338 to 469 kg/m³. In contrast, Factory C showed limited gains, maintaining high fuel usage even in the dry season, leading to increased operational costs. These findings align with prior research emphasizing the variability of energy efficiency across processing sites. This study highlights critical opportunities for enhancing energy efficiency, reducing costs, and advancing environmental sustainability in Rwanda’s tea sector. The findings support calls for cleaner energy transitions and investment in efficient biomass technologies. Key words: Tea processing, wood fuel efficiency, seasonal variation in fuel consumption, energy costs, energy audits in Rwanda.