To provide the juice company Mali Juisi with a stable power supply a diesel generator was installed as a backup system and to reduce energy costs a solar thermal system was constructed to heat up water that is used during the production process.


The small local fruit juice company Mali Juisi was founded in 1997 as an answer to a conducted local study on the agriculture development of the region Muleba in Tanzania. This study showed that there was plenty of fruit available to be traded on other markets, but the local farmers couldn’t effort the transport. Mali Juisi buys fruit from these local farmers to produce a fresh and high quality juice (pineapple, mandarin, mango and orange juice) that is sold in Muleba and the surrounding villages. This not only stimulates the local economy, but also gives the farmers a chance for a better life.  Since the company is financially stable and needs next to no support, a fund to support the children of employees and farmers was established. The local non-profit organisation is assisted by the Belgian non-profit organisation Mali Muleba. They frequently visit the factory to assist the staff with technical problems and management.

Unfortunately Mali Juisi suffers from inconsistent power supply making it difficult to ensure the quality and continuity of the production. Moreover the production process requires a lot of heat that is electrically generated. Not only a backup energy supply to ensure production during power failures was necessary, but also an energy optimization of the production process itself. Dit project was realised in cooperation with Konings NV and Encon Energy.

Energy supply and optimization

In February engineering students Sander Nulens and Joris Gerits travelled for a week to Tanzania to conduct a prospection on site and do all the necessary measurements. Back in Belgium they conducted a complete analyses of the situation to find the optimal energy solutions. Because of financial and/or technical issues of all the investigated possible renewable energy systems, a diesel generator (which was the worst-case solution) showed to be the best long term solution as a backup system. It is a relative low investment cost, easy to implement, exploit and maintain. For the energy optimization of the production process a solar thermal system turned out to be the most beneficial. It is a relatively simple, efficient and easily expandable system that heats up the water up to 60 °C in a central storage tank which stores the energy quite efficient. By distributing this water in the production process it can lower the total energy cost with at least 25 %. In August Sander travelled back to Tanzania to manage the implementation of the installations. The installed system is modular build and can therefore be easily extended with different types of renewable energy.