Development of an energy management solution for mine compressor systems

Abstract

Eskom is under increasing pressure to provide reliable and sustainable electricity. Demand Side Management (DSM), offers a short– to medium–term solution to this problem. During 2009, the mining sector consumed approximately 16% of the domestic electricity supplied by Eskom. This made the mining sector one of the major targets for Eskom–initiated DSM programmes. The mining industry uses compressed air for a wide variety of applications and production purposes. This creates many opportunities to reduce electricity consumption and operating costs. Reducing the airsystem demand may however not result in significant electrical energy savings, unless the compressed–air supply is accurately managed to meet the reduced demand. Until recently, compressor control in the mining sector generally consisted of operating the compressors continuously, regardless of the actual demand for compressed air. Excessive compressed air is blown off into the atmosphere resulting in energy loss. This usually occurs when the compressors are operated manually. A computer–controlled compressor management solution, which optimises the efficiency potential of the compressed–air supply, is required to obtain significant electrical energy savings. The need for such a solution was addressed by the development of an energy management solution for mine compressor systems. This solution is referred to as Energy Management System (EMS) and is capable of starting, stopping, loading and unloading compressors. In addition to this, compressor output can be controlled to maintain a desired pressure set–point. In this study, the development and implementation of EMS on ten different mine compressor systems is presented. Automatic compressor capacity control was implemented, while an operator manually initiated compressor starting; stopping; loading and unloading, according to EMS control schedules. Centralised compressor control is one of the main advantages offered by EMS, especially for compressed–air systems with multiple compressor systems at different geographic locations. EMS facilitated effective and sustainable electrical energy reductions for all these compressed–air systems.