Energy consumption analysis for the Malawian tea industry

Abstract

The tea industry in Malawi is energy intensive and is one of the top consumers of energy in the country. This study presents an energy consumption analysis for eight representative tea factories in Malawi. Primary data were collected using structured questionnaire, detailed audits of records, physical instrumentation measurements, interviews and direct observation. Results indicate that thermal energy share is on average 85% while electrical and manual energy is on average of 14.97% and 0.03%, respectively. The specific electrical and thermal energy consumption was found to be 0.64 kWh/kg and 13.41 kWh/kg of made tea, respectively, which is consistent with the data (0.4 - 0.7 kWh/kg and 4 - 18 kWh/kg) reported in the literature. Average specific fuel consumption was calculated to be 3.55 kg wood/kg of produced tea compared to 1.7 kg wood/kg of made tea quoted for tea factories in other producing countries. In addition, results of this study show that sizeable amounts of energy can be saved using a variety of interventions such as variable speed drives, waste heat recovery, improving combustion efficiency, use of energy efficient motors, use of flat belts, and alternative energy sources. This analysis serves as a benchmark for the tea industry and as a base case for stimulating changes aimed at more efficient energy utilization.