Member Case Studies

Introduction

In an effort to modernise its energy infrastructure, the City of Cape Town (COCT) undertook a significant upgrade to its data centres. The primary objectives were to enhance reliability, improve safety, and support sustainability goals. This case study outlines the challenges encountered and details the innovative solution implemented through WEST's ENVOY Series 10 energy storage system.

The Challenge: Outdated Lead-Acid Batteries

COCT's data centres previously depended on lead-acid batteries to bridge the gap between grid power and backup generators. While these batteries served their purpose, they posed several critical challenges:

• Frequent Replacements and High Costs: The batteries required replacement every three years, resulting in substantial maintenance costs and operational downtime.

• Downtime Risks: The system lacked redundancy; a single module failure could trigger a complete system shutdown, jeopardising essential digital services.

• Degradation and Inefficiency: Over time, battery performance deteriorated, leading to reduced efficiency.

• Safety Concerns: As chemical-based batteries, they generated heat, required parasitic cooling, and carried a fire risk—factors that increased energy demands and potential hazards.

• Limited Alternatives: Lithium-ion batteries were not a viable option due to similar fire risks and stringent safety requirements.

These challenges not only undermined reliability but also hampered the city’s ambitions for a sustainable and resilient infrastructure.

The Solution: WEST's ENVOY Series 10 Electrostatic Supercapacitor Technology

To address these issues, COCT partnered with WEST (Wright Energy Storage Technologies) to implement the ENVOY Series 10, an advanced energy storage solution utilising electrostatic supercapacitor technology. This system stands as a future-proof alternative to traditional chemical batteries, delivering enhanced performance, safety, and longevity.

Key Features of the ENVOY Series 10

• High Discharge Rate: Capable of a 5C (12-minute) discharge rate, enabling rapid and efficient energy delivery.

• Modular Design: Each rack includes 10 x 1.78kWh modules, totaling 17.8kWh per rack and 84kW output. With six racks (107kWh total), the system can support a 500kW load seamlessly.

• Flexibility: Users can select fast power delivery or extended duration—providing 500kW for 12 minutes or 1W for 12.2 years.

• Industry-Leading Warranty: The system is backed by a 10-year warranty for long-term reliability.

• Robust Infrastructure: Supported by a 200-amp, 480V UPS, the system ensures continuous, uninterrupted power.

This deployment eliminates the short replacement cycles and high costs associated with lead-acid batteries, while also boosting operational resilience.

Addressing the Pain Points

The ENVOY Series 10 directly resolves the legacy system’s shortcomings:

• No Downtime: Built-in fault tolerance enables the system to operate even if a single module fails.

• Negligible Degradation: Electrostatic storage maintains high performance with minimal wear over time.

• Non-Chemical Architecture: The system produces negligible heat, eliminates fire risk and thermal runaway, and does not require additional cooling. This results in superior safety and energy efficiency.

Additional benefits include:

• 500kW Capability: High-power output suitable for mission-critical applications.

• 100% Usable Capacity: Full utilisation with no losses typical of chemical batteries.

• Extreme Temperature Resilience: Operates from -40°F to +150°F (-40°C to 65°C) without degradation, eliminating the need for complex environmental controls.

• 45-Year Design Life: Provides a long-term solution that surpasses traditional options in longevity.

• Modular and Scalable: The system can be expanded easily by adding units that integrate seamlessly.

• Safety Classification: Classified as non-dangerous goods, with no hazardous materials, heat generation, or fire risks.

• Sustainability Focus: Manufactured in a net-zero facility and features self-monitoring modules for intelligent diagnostics and proactive maintenance.

A Resilient Future for Cape Town

By transitioning to the ENVOY Series 10, the City of Cape Town has secured uninterrupted power supply, reduced costs, and advanced towards a more sustainable energy infrastructure. This upgrade supports vital digital services while aligning with broader environmental objectives. The system’s robust performance establishes a new benchmark for flexibility and reliability, even under extreme conditions.

Conclusion: Setting a Benchmark for Backup Power

The successful implementation of WEST’s electrostatic supercapacitor technology at COCT illustrates the potential of innovative energy storage solutions. As the demand for resilient infrastructure increases, technologies like the ENVOY Series 10 are paving the way for safer, more efficient, and scalable systems. Wright Energy Storage Technologies continues to lead in providing future-proof solutions for critical applications.