How South Ocean Overcame Load-Shedding Challenges with SigenStor?

South Africa’s ongoing load-shedding has long been a challenge for households and businesses alike. While temporary improvements to the power grid in 2024 provided some relief[1], the return of load-shedding in early 2025[2] again posed significant operational challenges for industries.

At the same time, Eskom’s[3] electricity tariffs have been steadily rising, with a staggering 653% increase from 2007 to 2022, according to PowerOptimal[4]. Eskom continues to push for even higher rates. In early 2025, the National Energy Regulator of South Africa (Nersa) granted Eskom a 12.7% tariff hike for the 2025/26 period—far below the 36.1% increase the utility had requested[5]. The combination of rising costs and ongoing power supply instability has placed immense pressure on businesses.

This case study explores how South Ocean Electric Wire, a leading cable manufacturer, turned to Sigenergy’s C&I energy storage system to ensure uninterrupted production and support its sustainability goals amidst these challenges.

Project Background and Challenges

South Ocean Electric Wire, located in Alberton near Johannesburg, operates a 40,000-square-meter factory that runs 24/7, producing 2,850 tons of cable each month. Frequent load-shedding disrupted operations, causing costly production halts and increasing dependence on diesel generators. These generators, while offering temporary relief, posed high fuel and maintenance costs, and lacked the ability to provide seamless power transitions. The company needed a more stable, eco-friendly but also powerful energy solution to protect its operations especially during power outages.

Energy Storage Solution provided by Sigenergy

Sigenergy responded with a customized energy storage solution that included:

• 96 SigenStor units, each paired with a 25 kW three-phase inverter, providing a total storage capacity of 4.1 MWh.
• 2 Energy Gateways with a 1,200 kW power output, ensuring seamless grid-to-backup power switching.
• Integration with a 2.05 MW solar PV system, expected to generate over 3 million kWh annually once operational, reducing grid dependency and boosting energy independence

This solution not only ensured a reliable backup during load-shedding but also supported the company’s move towards cleaner, renewable energy.

The Three Biggest Issues South Ocean Faced—and Solved

1. Ensuring Uninterrupted Production

A key highlight of the solution is the Energy Gateway, custom-designed by Sigenergy in collaboration with local partners, with a power output of up to 1,200 kW to meet the specific needs of South Ocean Electric Wire. This makes the Energy Gateway the largest of its kind in the South African market. Thanks to this advanced feature, the system can seamlessly transition between grid and backup power without notice, providing up to five hours of backup during load-shedding when paired with the 4.1 MWh energy storage system, effectively preventing production downtime.

The entire process—from design and production to installation—was completed impressively fast, taking just two months, underscoring Sigenergy’s technical expertise and commitment to meeting urgent customer needs.

The SigenStor Energy Gateway consolidates the functions of an AC combiner, backup power unit, and Automatic Transfer Switch (ATS) into a single, compact device. This integration reduces the need for additional equipment, simplifies installation, and improves system reliability. Furthermore, additional generator can be connected to Energy Gateway for further backup if needed. With RJ45 network communication cables, data transmission is faster and more reliable, significantly enhancing overall system stability.

In contrast, many competing systems require separate ATS units with limited capacity (typically under 250 kW), leading to more complex wiring and slower communication. These systems rely on CAN bus connections, which result in slower, less stable data transmission and longer, more cumbersome installation processes.

Copyright Photo From: Herholdt’s Group (2025). Size Matters – We’Ve Got Proof (Online) Available at: Size Matters - And We've Got Proof! - YouTube [Accessed 26 Feb. 2025].

2. Reducing Operational Costs

The system delivers significant cost savings through:

• Peak Shaving: Discharging energy during high-demand periods reduces peak power demand and lowers associated charges.
• Time-of-Use Optimization: The system charges during off-peak hours when electricity rates are lower and discharges during peak hours, avoiding higher grid prices.
• Replacing Diesel Generators: Eliminating diesel generators has cut fuel, maintenance, and environmental compliance costs, while also reducing noise and emissions.

3. Driving Green Transformation

South Ocean Electric Wire is integrating a 2.05 MW solar PV system, expected to generate over 3 million kWh of clean energy annually. This integration will increase the use of renewable energy and strengthen the company’s commitment to energy independence.

Advantages of Sigenergy’s SigenStor System

1. Innovative Design

The DC-coupled design of SigenStor integrates the Energy Management System (EMS), inverter, and PCS (power control system) and battery pack (energy storage system) into a single unit, eliminating the need for additional devices like data loggers. This streamlined approach improves efficiency, reduces installation time, and cuts costs. Its modular design and quick connector technology further simplify installation and allow for easy expansion as business needs grow.

2. Enhanced Safety

The system’s low-voltage design (32.85V) minimizes risks, while additional protective features—including temperature sensors, internal fire extinguishers, and aerogel-insulated pads—ensure safe operation and mitigate potential hazards, making it leading safe energy storage system in the industry.

3. Minimum Maintenance

With an IP66 rating, the system is built to withstand harsh conditions, making it suitable for both indoor and outdoor installations. Its parallel architecture allows for the easy replacement of individual battery modules without disrupting overall system operation, reducing maintenance requirements and lowering long-term operational costs. In contrast, other energy storage solutions often demand frequent system checks, which can lead to higher maintenance costs and require shutting down the entire system during inspections.

Conclusion

The successful deployment of SigenStor has enabled South Ocean Electric Wire to tackle the challenges of load-shedding while advancing its sustainability goals. By ensuring uninterrupted production and significantly lowering operational costs, the company has boosted efficiency and reduced energy expenses.

As the solar PV system comes online, South Ocean Electric Wire will further decrease its reliance on the grid, achieving greater energy independence. This case demonstrates the transformative power of energy storage solutions, not only in overcoming energy supply challenges but also in driving cost savings and fostering sustainability in industrial operations.