Temporary Battery-Backed Monitoring Power System

JCE was appointed to design, manufacture and commission a fully ATEX & IECEx certified Temporary Power Supply Package to support critical subsea cable monitoring on the Okha offshore facility in Western Australia.

The system was engineered to maintain uninterrupted power to a specialist signal injection and insulation monitoring system during a 75 day period when the primary support vessel would be removed for scheduled maintenance.

The client required a self-contained, hazardous area compliant, DC power solution capable of sustaining continuous monitoring and active protection of subsea cables connected to a floating production system.

With the support vessel temporarily removed, no AC supply would be available. However, cable integrity needed to be preserved, monitored and actively protected to prevent insulation degradation or failure across ageing subsea infrastructure.

The solution needed to:

• Operate autonomously for a minimum of 75 days
• Be certified for hazardous offshore environments (ATEX & IECEx)
• Integrate with existing turret junction boxes
• Be deployable in an extremely space restricted environment
• Allow rapid commissioning within a limited offshore access window

Due to the production critical and highly technical nature of the installation, specialist commissioning expertise was required to ensure safe integration with the monitoring system.

Harsh Offshore Environment

The installation location is exposed to severe offshore weather conditions, including high winds, salt spray, heavy rain and constant marine corrosion. Equipment therefore needed to be engineered for long-term reliability in an aggressive marine environment while remaining compact enough to fit within the limited available space on the structure.

To ensure durability and operational integrity, the system was designed with weather protected support frames and high ingress protection ratings, allowing it to withstand prolonged exposure to harsh offshore conditions.

Offshore Constraints

The system was installed on a floating production structure with limited deck space, restricted lifting access and no permanent accommodation facilities.

Personnel access was time critical, with a 5-7 day installation window.

No Available AC Power

During the 75 day vessel absence, no charging supply would be available. The battery system therefore had to be precisely sized to operate autonomously for the full monitoring period.

Logistical Complexity

Personnel were required to travel over 1,400 km north of Perth before helicopter transfer offshore. Installation and commissioning had to be completed efficiently before vessel disconnection.

JCE engineered and supplied a fully integrated Temporary Battery Power System comprising:

Battery Assemblies

• 8 × ATEX (Ex eb) & IECEx Certified
  • 24Vdc
  • IP23 (IP66 protection)
  • BC-4 140Ah (C20) Assemblies
  • Configured as 4 sets delivering 48Vdc output

Battery Isolation & Management

• 4 × ATEX (Ex d) & IECEx 32A, 48Vdc Battery Isolator Assemblies
• 1 × ATEX (Ex d) & IECEx 4-Way BMS Assembly
• 1 × ATEX (Ex d) & IECEx 4-Way Card Assembly (Client free-issue equipment supplied by Viper Innovations Ltd)

Charging Infrastructure

• 2 × ATEX (Ex d) & IECEx 48Vdc, 25A Battery Charger Assemblies
  • Primary & Secondary units
  • Supplied in protective transport cases
  • Designed for post-deployment recharge once vessel power returned

• Weather shield support frames
• Plug-and-play configuration
• No glanding required for initial deployment
• Integrated PLC programming and communication protocol testing

The batteries were carefully sized to sustain the full 75 day monitoring period without recharge. Once the vessel returned, chargers could be connected directly to the BMS for controlled recharge.

JCE also provided offshore pre-checks and commissioning support, working alongside the Viper specialist engineer to ensure safe installation and operational readiness.

• Maintained continuous subsea cable integrity monitoring and protection during vessel absence
• Eliminated risk of insulation degradation across ageing subsea infrastructure
• Delivered a fully autonomous hazardous area compliant solution
• Achieved successful installation within a restricted offshore time window
• Preserved production asset integrity during planned maintenance downtime

The system remains installed for potential future use, demonstrating JCE’s capability to deliver robust, specialist offshore solutions under complex logistical and environmental constraints.

This performance was also formally recognised by project stakeholders:

JCE’s performance was recognised by project stakeholders, including Viper Innovations Ltd and Woodside Energy, highlighting the company’s commitment to delivering high quality engineered solutions under demanding conditions.

• ATEX & IECEx Certified (Ex eb / Ex d) – Fully compliant for hazardous offshore environments
• 48Vdc Autonomous Battery Architecture – Sized for 75 day standalone operation
• Integrated BMS & PLC Programming – Full communication protocol testing completed
• Plug-and-Play Deployment – Reduced offshore installation time
• Redundant Charging System – Dual 25A chargers for post-deployment recovery
• Weather Protected Structural Frames – Designed for exposed marine conditions

From specialist offshore battery systems to fully integrated hazardous area power solutions, JCE delivers engineered packages designed for reliability in the most demanding environments.

To discuss your next offshore or hazardous area power project, contact the JCE team.