The three primary manufacturers of High-Voltage Gas-Insulated Switchgear (GIS) for offshore substations—Hitachi Energy, Siemens Energy, and GE Vernova (along with others like Schneider Electric)—have traditionally relied on SF6 as the insulating medium. In recent years, the industry has shifted toward environmentally friendly alternatives, such as clean air (Siemens Blue GIS) and fluoronitrile-based mixtures (Hitachi EconiQ and GE g³), driven by regulations and sustainability goals.

Regardless of the insulating medium, core control and protection schemes remain consistent across manufacturers, as do many installation methods and interface requirements.

At ReNova Energy Solutions, we specialise in Integration Engineering—the critical Balance of Plant (BoP) discipline where the topside EPC contractor provides comprehensive support for GIS installation, ensuring safe, efficient, and compliant integration.

• Room Layout and Space Optimisation — Designing GIS and transformer rooms to accommodate equipment dimensions, maintenance access, and future expansions while minimising topside footprint.

• Structural and Foundation Support — Precise load calculations for heavy GIS modules, ensuring vibration resistance and alignment with offshore motion criteria (e.g., DNV standards).

• Cable Routing and Containment — Robust HV/MV/LV cable support systems, incorporating short-circuit forces, thermal expansion, and redundancy in high-risk areas.

• Earthing, Bonding, and Lightning Protection — Comprehensive grounding networks to mitigate electromagnetic interference and ensure personnel safety.

• HVAC and Ventilation Zoning — Managing heat dissipation from GIS and associated equipment, with zoned systems for pressurisation and fire safety.

• Fire and Gas Detection/Suppression — Integrated FM200 or equivalent systems tailored to GIS room hazards.

• Cranage and Material Handling — Coordinated lifting points, access doors, and removal routes for installation and future maintenance.

• Interface Coordination — Seamless integration with protection/control systems, SCADA, and network interfacing.

Drawing from our extensive experience in offshore wind (e.g., Inch Cape, Moray West), marine FPSOs, and onshore process plants, ReNova Energy Solutions leverages proven oil & gas expertise to deliver Balance of Plant solutions for emerging renewables technologies—including hydrogen production, Battery Energy Storage Systems (BESS), and data centres.

We focus on practical, client-focused outcomes that ensure on-time, cost-effective project delivery in the transition to sustainable energy.

Seamless Integration of High-Voltage GIS in Offshore Substations

Key considerations we address for effective GIS integration include: