Power Factors’ EMS supports complex hybrid off-grid power system at gold mine

Power Factors’ Local EMS (Energy Management System) has been successfully deployed to manage a complex hybrid off-grid power system at a gold mine, enabling the integration of renewable energy sources into its operations. The system integrates a 34 MW photovoltaic solar plant and an 18 MWh battery energy storage system (BESS) with several heavy fuel oil (HFO) generators and is projected to reduce greenhouse gas emissions by over 500 kilotons throughout the mine’s lifetime.   

Already in operation for nearly a year, the EMS’s primary goal is to maximize solar energy penetration while maintaining the minimum technical load of the HFO units and ensuring grid stability. Although the BESS acts as a buffer by injecting or absorbing power as needed, cloudy skies can still pose stability challenges. That’s where the EMS steps in, playing a critical role in improving overall system performance and penetration limits while ensuring consistent power quality and secure load supply.

To enhance the system's performance during cloud events, a weather forecasting system (WFS) based on cloud cameras was installed onsite. The WFS informs the EMS about sudden fluctuations (short, medium, and long-term) in PV production. The short-term WFS detects nearby clouds, measures cloud cover, locates cloud shadows, and predicts their future movement. With forecast times ranging from 30 seconds to 30 minutes, the WFS helps manage ramp rates and spinning reserves, optimizing control of the off-grid system under varying solar conditions. This also protects the HFO units, as rapid, uncontrolled fluctuations in intermittent PV generation could damage their mechanical components. 

While the HFO generators serve as the main grid-forming elements of the hybrid system, the BESS is also configured to operate in grid-forming mode as a voltage source alongside the HFO units, enabling seamless transitions to islanding mode when necessary. Additionally, the BESS functions as a primary frequency response element, performing frequent micro-cycles to maintain frequency stability close to the reference value. 

Power Factors’ Local EMS also conducts dynamic and static load shedding to ensure system stability. Load shedding occurs when there is insufficient reserve capacity to meet demand, causing power to be automatically disconnected from certain predefined consumers in order to balance electricity supply and demand.

As with all assets managed by Power Factors, we continuously support the system, the independent service provider (ISP), and the owner in their efforts to maintain a reliable off-grid electrification system while achieving fuel savings of approximately 180 million liters over the asset's lifetime. 

To learn more about Power Factors’ local monitoring and controls, get in touch!