Developing a dynamic operational energy management strategy for energy intensive industries

Abstract

Fossil fuels are likely to supply most human energy needs for the 21st century. However, these fuels are exhaustible and have adverse environmental effects when combusted. To reduce the negative environmental effects, the onus is on energy consumers to reduce their energy consumption by being more energy efficient. Industry is responsible for approximately 29% of world energy consumption. As international studies have estimated that efficiency improvements of between 5% and 30% are possible in this sector, it has become a prime target of policy and improvement initiatives globally. A history of low energy prices in South Africa has resulted in poor energy management practices and inefficient energy use. With recent energy price increases, specifically electricity prices increasing 271% since 2000, South African industry must improve its energy efficient practices. Due to a strained economy, there is no capital for large energy efficiency improvement projects, but operational energy management can provide energy savings of 5% with very little capital outlay. Operational energy management consists of measurement, analysis and feedback to reduce operational energy waste. The foundation is to measure energy usage accurately enough that the derived data is reliable. This data must be analysed, resulting in information regarding the actual energy performance. Finally, effective feedback ensures that the right person receives the right performance information, empowering the person to act and thereby improve energy performance. Existing practices in South African industry relevant to operational energy management were reviewed and found to be not of a suitable level of maturity yet. Several additional barriers were identified, such as a lack of knowledge on how to approach applying operational energy management to a complex industrial facility, how to effectively implement it, and how to manage energy data. It was also evident that most existing research in this field is either very high level, or focuses on a very specific sub-component of operational energy management. No literature could be found that provides a comprehensive methodology for implementing operational energy management in industry. Most literature focuses either on high level guidance and policies, or offers very low level and technical information. Available literature was not vertically integrated, meaning that only a part of the process (such as analysis) was covered with no support for integration with other steps. The need for a comprehensive methodology for the South African energy intensive industry was identified. This study develops a system-based approach for integrated operational energy management in South Africa. A methodology for implementing energy measurement is developed. This methodology provides a systematic process for ensuring the correct measurement of important energy streams. A method to effectively manage measurement quality, thereby ensuring that measurements are verified, is also developed. Effective management of energy data is implemented, ensuring that the provided data is reliable and available where needed. The second part of the methodology is performing accurate analyses. This process uses a systematic process to accurately identify energy drivers acting on each system in the facility. This information and data are then used to develop a performance evaluation model of the system, based either on mathematical principles or historical and metadata, depending on available infrastructure. Finally, a methodology for effective operational energy management feedback is developed. This process is designed to ensure that feedback is integrated into facility operations by incorporating all relevant stakeholders. Guidelines are developed to ensure that the developed feedback is effective at promoting improved energy performance. This comprehensive methodology was implemented on a South African gold mining group as a case study, which demonstrates the methodology, identifies key challenges and validates the proposed methodology. Validation is done by measuring energy cost savings achieved by the group. The implementation contributes to a total of R41.9 million in cost savings in specific isolated cases for one year. Furthermore, through improved operational control, a R25.3 million annual cost saving was realised on the group's total bill