As renewable energy systems move offshore, power transmission becomes one of the most fascinating engineering challenges of our time. From floating wind farms to wave energy converters, the demand for dynamic subsea umbilicals, is growing rapidly.
At DeRegt, we’ve spent over 50 years engineering dynamic subsea cables for some of the most demanding environments on Earth. Now, that experience is helping renewable pioneers design cables that are efficient, flexible, and built for the long haul. So how does a dynamic umbilical actually work — and what goes into designing one that perfectly fits your renewable project?
Let’s dive into the five key building blocks that bring a power export cable to life.
- Power Transmission
- Data Transmission and Fiber Optics
- Sheaths and Tapes
- Armoring
- Additional Components
Let’s dive into each one now to discover how they matter for your projects.
1. Power transmission: the beating heart of every cable
For most renewable energy systems, power transmission is mission-critical. The backbone of this process is copper, which still is the most reliable material for subsea conductors. The voltage level determines the design. Below 5 kV, we use single-layer power cores. Above that threshold, we switch to triple-layer extruded cores with individual earth shields, capable of handling up to 33 kV. These advanced cores are what keep your system running smoothly, whether you’re harvesting tidal flow or converting wave motion into electricity.
Designing the perfect power core is about balance. We size every layer to match your power profile, operating depth, and movement patterns, because there’s no such thing as a one-size-fits-all umbilical.
2. Data transmission and fiber optics: the cable’s nervous system
Every renewable system needs to think as well as move. That’s where data transmission comes in, managing sensor feedback, performance monitoring, and control signals. For small data volumes, copper pairs can do the job. For high-speed communication or real-time control, fiber optics take the lead. And there’s a new frontier emerging: fiber-based sensing cables that track temperature, strain, and motion in real time. These “smart cables” will soon play a vital role in preventive maintenance and offshore system health monitoring.
3. Sheaths and tapes: keeping it all together
What’s inside the cable matters. But what’s around it matters just as much. The cable’s sheaths and tapes provide strength, sealing, and safety. We typically use watertight polyethylene layers, reinforced with water-blocking tapes when needed. Inner and outer semiconductive layers manage electrical stress, while metallic tapes provide a stable ground reference. Every subsea environment is unique, from shallow tidal bays to deep ocean energy farms, so protection levels are fully customizable.
We tailor the sheath design to your operating depth, handling system, and fatigue requirements. That’s where a strong collaboration really makes a difference.
4. Armoring: the cable’s exoskeleton
This is where strength meets resilience. Armoring gives the umbilical its mechanical backbone, protecting it from tension, torsion, and even the occasional curious shark. Dynamic cables typically use two counter-wound armor layers, creating a torque-balanced design that moves equally well in any direction. The entire assembly is wrapped in a durable outer sheath for abrasion and corrosion resistance. A well-balanced armor system doesn’t just survive motion, it thrives in it.
5. Beyond the cable: the full system in motion
A dynamic umbilical is never just a cable. It’s part of a complete energy system. That’s why we always consider the interfaces and movements around it:
- Landing points and load transfer pieces distribute mechanical tension evenly, protecting both the cable and the device.
- Terminals and plugs, from dry-mate to wet-mate connectors, ensure safe and simple electrical and data integration.
- Stress management configurations like Lazy-S or J-lay layouts, prevent fatigue at the cable’s transition from static to dynamic.
Designing these details early can save months of redesign later — and that’s where we love to co-engineer solutions with our partners.
Designing for success, together
Every renewable project faces unique conditions — tides, currents, space constraints, and lifetime targets. That’s why we don’t just deliver cables; we co-develop solutions. Our process is about translating your data into proven design. Creating a custom dynamic cable typically takes around six months, but with the right collaboration, every step brings you closer to reliable, scalable offshore energy.
If you’re developing a wave, tidal, or floating wind project, we’d love to explore it with you.
