South Africa regularly experiences power outages, known as load shedding, which disrupt everyday life and business. Rosebank Mall in Johannesburg is addressing this challenge with an innovative energy management system. The mall’s new hybrid power setup helps it stay lit and operational even when the national power grid falters. This article explains how the system works and why it’s important.
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What Is a Hybrid Power System?
A hybrid power system combines different sources of energy to provide a reliable electricity supply. Instead of depending on one source, like the national electric grid, the system uses a combination of solar panels, batteries that store electricity, and backup generators that run on fuel. This mix makes the power supply more stable and less vulnerable to interruptions.
The Components of Rosebank Mall’s System
Rosebank Mall’s system includes:
- Solar Panels (1.3MW): These panels capture sunlight and convert it into electricity during the day.
- Battery Bank (7.2MWh lithium-ion): The batteries store extra energy produced by the solar panels. This stored energy can be used at night or when the sun isn’t shining.
- Inverter (4.5MW): This device converts stored direct current (DC) electricity from the solar panels and batteries into alternating current (AC) electricity, which powers the mall.
- Dual-Fuel Generators (Three 1MW units): These act as backup power, running on a mix of diesel and natural gas to reduce emissions and fuel consumption.
How Smart Energy Management Works
The system uses a real-time monitoring and control platform. Think of it as the system’s brain, scheduling and managing when to use solar energy, battery power, or generators based on factors like:
- Energy availability: Using solar power when the sun shines.
- Energy cost: Charging batteries at night with cheaper grid electricity and using this stored energy during expensive peak hours.
- Demand: Turning on generators only when needed to meet high electricity needs or when solar and battery supply is insufficient.
This smart balancing act maximizes efficiency and keeps costs low.
Energy Arbitrage: Saving Money by Timing Energy Use
Energy arbitrage is the practice of buying electricity when it is cheap (usually at night) and using or selling it when it is expensive (daytime peak hours). Rosebank Mall uses this strategy by charging its batteries overnight and using that energy when electricity prices rise. This reduces the money spent on power from the grid.
Why Use Dual-Fuel Generators?
Generators often run on diesel, a costly and polluting fuel. Rosebank Mall’s generators also use natural gas, which burns cleaner and more efficiently. By blending these fuels, the mall reduces both emissions and fuel expenses by over half. This supports sustainability and lowers operational costs.
Ensuring Reliable Power Supply
The system’s components are connected and controlled by a smart controller from ComAp. This device manages smooth transitions between solar, battery, and generator power without causing interruptions. Transformers convert the electricity to the correct voltage for the mall’s use, ensuring steady and reliable power for shoppers and tenants.
Environmental Benefits
By cutting diesel use and increasing solar energy, the mall decreases its carbon footprint. Future plans aim to double solar power capacity, improving energy independence and allowing the mall to possibly share excess power with the city grid.
Impact on Business and Customers
Power outages harm businesses by forcing closures and disrupting services. With its hybrid system, Rosebank Mall experiences fewer outages, keeping shops open and customers happy. This reliable power supply also provides peace of mind for tenants planning their operations.
Use of Technology in Building the System
The mall’s hybrid power project used advanced digital tools like Autodesk Construction Cloud and HoloBuilder. These tools allowed engineers and builders to collaborate in real-time, track progress with 3D pictures, and solve problems faster. This coordination reduced construction delays and lowered costs.
Why It Matters
South Africa’s power challenges affect millions daily. Rosebank Mall’s system is a practical example of how smart technology and renewable energy can keep essential services operating during outages. It provides a model other businesses can follow to become more resilient and sustainable.
