Using energy balances to evaluate electricity savings projects on platinum mines

Abstract

The platinum mine industry is under economic pressure due to decreased production and increased electricity prices. Implemented energy saving strategies and projects aim to reduce the electricity consumption, but this takes time to bring about change. To speed up the process, the platinum mining sector focused on easily achievable savings. The impact of these savings is visible when evaluating the performance by means of isolated boundaries on which the projects are implemented. However, the average impact of energy saving initiatives is less than 10% of the electrical energy consumption of the mine. It is therefore required to evaluate the holistic impact of individual projects on a high level and not only according to the isolated boundaries. The need was identified to develop a framework that evaluates individual energy savings projects on whole facility level and also considers the uncertainty associated with facility noise. The developed framework consists of four phases, namely; data quality, energy balances, energy monitoring, and savings quantification. The framework was tested and verified by applying it to a case study that consists of three boundary levels. The first level represents the high-level energy balance that is done holistically. The second level is a reticulation energy balance, while level 3 focuses on the energy balance of a subsystem, such as a compressed air network. The energy balances showed differences that ranged between -0.3% and 1.0%, while implemented energy savings projects had an impact of 3% of the total energy used. This impact was evaluated by using the bottom-up traceability method to consider the differences within the system. The framework aims to evaluate the whole facility impact of individual energy savings projects that were implemented within isolated boundaries. I would like to express my gratitude towards Prof Edward Mathews and Prof Marius Kleingeld for providing me with the opportunity and resources to conduct this research. Thank you to ETA operations (Pty) Ltd and Enermanage (Pty) Ltd for the financial support to complete this study. Dr Andries Gous, thank you for your expert guidance and willingness to always go the extra mile. And for all your help in compiling a good quality dissertation, your mentoring made this study possible. Special thanks to my parents and sister for all your support and love. Without whom I would not be the woman I am today. No word can explain how much your guidance and believing in me has meant, especially in compiling my dissertation. To my friends, thank you for the support you provided while I wrote this dissertation. Thank you for understanding when I had to work. A sincere thank you to Hein and Wendy Eksteen, my guidance in Christ, without whose support this dissertation would have been a much larger challenge. Most important, I would like to thank God Almighty, for providing me with the strength, knowledge and capability to follow my aspirations in life.