Withering of tea is an essential and important processing stage in black tea manufacturing. At present, there are about 700 factories in operation processing black tea. It is absolutely important to have a uniform withering within a reasonable time period which varies from 12-16h. Withering consumes comparatively high electrical energy which is about 48% out of the total electricity consumption in the tea factory. In order to reduce the power consumption, some factories installed Variable Speed Drives (VSDs) for withering troughs. However, all the operations are done manually. As such, the benefit of using VSDs is negligible.
The Tea Research Institute with NSF support developed a system to reduce the electricity consumption establishing an automatic control system for VSD. Technical expertise, for this project, especially for electronically controlled parts is being provided by the University of Moratuwa.
Test trials have provided promising results with saving of electrical energy up to 0.18 kWh/kg. In this context, if the adaption rate of the newly developed control system for tea withering is 60% of the total 700 factories of the country, about 40 GWh annual saving of electrical energy can be expected from the tea sector. The project is expected to be completed within three months and the system will be available for the stakeholders in the near future. The successful completion of this project is undoubtedly essential for the sustainability of the tea industry in Sri Lanka.