Floating vs Fixed Offshore Wind Turbines – Key Differences Explained

Offshore wind energy is expanding quickly. As the industry moves into deeper waters, a key decision comes up: should wind turbines float or be anchored to the seabed?

Both floating and fixed-bottom turbines are used to generate clean electricity offshore. They serve the same purpose but function very differently. If you're working in renewables, whether in operations, training, or engineering, it’s important to understand how these two systems compare.

Let’s break it down.

What Is a Fixed-Bottom Offshore Turbine?

Fixed-bottom turbines are the traditional offshore design. These turbines are physically connected to the seabed using a permanent foundation. The foundation types vary depending on water depth and seabed conditions, but the goal is always the same: to keep the structure anchored in place and stable in the water.

The most common type is the monopile, which is a single steel tube driven straight into the seabed. It's often used in shallower waters, up to around 30 or 40 metres deep. In deeper areas, jacket foundations are used. These are more like steel frameworks, built to spread the weight and improve stability. In some areas, gravity base structures are placed directly on the seabed using their own weight to stay in place.

This fixed approach is reliable, and it’s what you’ll find on the majority of the world’s offshore wind farms today. The technology is well established, and there’s a large supply chain already in place to support it.

What Is a Floating Offshore Wind Turbine?

Floating turbines work differently. Instead of being attached directly to the seabed, the entire structure floats on the water surface. It's held in place by a system of mooring lines and anchors. The turbine remains upright, even though the base itself is not fixed.

Several designs exist for floating platforms. Some use a deep cylindrical shape that hangs vertically underwater, called a spar buoy. Others rely on wide, buoyant structures with multiple legs, known as semi-submersibles. There's also a design called a tension leg platform, which stays stable using vertical anchors that keep it pulled downward.

These floating systems allow turbines to be placed in much deeper water, often far beyond what fixed-bottom foundations can handle. This opens access to areas with stronger, more consistent winds, and less competition for space.

Depth and Location: Where Each System Works

Fixed-bottom turbines work best in waters up to 60 metres deep. That typically means nearshore locations, such as the North Sea, parts of the Baltic, and shallow coastal areas around the UK and Europe.

Floating turbines, on the other hand, are designed for deeper waters. They can be installed at depths of 60 metres or more, even over 1,000 metres in some cases. This allows developers to move further offshore into areas where fixed foundations simply aren’t practical.

The deeper you go, the more challenging it becomes to build a stable foundation directly on the seabed. Floating platforms solve this problem, allowing turbines to operate in places previously out of reach.

Installation and Access

The way these turbines are installed also varies. Fixed-bottom turbines require heavy offshore equipment, pile driving, and seabed preparation. Construction is highly dependent on weather and sea conditions, and the entire process must be managed from offshore vessels.

Floating turbines are usually assembled in port, then towed to their final location and anchored in place. This reduces the need for long offshore construction campaigns. It also makes some types of maintenance easier. In some cases, the entire floating unit can be towed back to shore for major repairs.

However, the mooring and anchoring systems for floating turbines introduce new challenges. Managing anchor chains, cable tension, and dynamic power cables requires different technical expertise and a new set of operational procedures.

Performance and Environmental Impact

Both systems are designed to withstand harsh offshore conditions. Fixed-bottom turbines are extremely stable and well understood by the industry. Floating turbines, while newer, are designed to remain upright and operational even in rough seas.

When it comes to environmental impact, fixed-bottom turbines tend to disturb the seabed more during installation, particularly during pile driving. Floating turbines cause less seabed disruption, but their mooring systems may move with waves and currents, potentially affecting marine life in different ways.

Over time, both types of foundations can become artificial reefs, attracting marine species. Environmental monitoring is still ongoing to understand the full impact of both technologies in different ocean regions.

Cost and Scalability

At present, fixed-bottom turbines are generally cheaper to build and install. The infrastructure and supply chain have been developed over the past two decades, which helps keep costs low.

Floating turbines are more expensive today, mostly due to newer technology and smaller production volumes. But the cost is coming down. As more projects are built and floating systems are standardised, the economics are expected to improve. Several countries are investing in floating wind at scale, hoping to bring the price closer to fixed-bottom levels within the next decade.

Floating wind also helps avoid some of the costs and delays linked to complex seabed conditions. In regions with deep water close to shore, floating systems may even become the cheaper option in the long run.

Real-World Examples

One of the most well-known fixed-bottom wind farms is Hornsea in the UK. Located in the North Sea, it uses monopile foundations and has become one of the largest wind farms in the world.

On the floating side, Hywind Scotland was the world’s first floating wind farm. Developed by Equinor, it has been operating successfully since 2017. Despite harsh North Atlantic conditions, it has consistently delivered high capacity factors, proving that floating wind can be both reliable and efficient.

Projects like WindFloat Atlantic in Portugal and Kincardine Offshore Wind in Scotland continue to build confidence in floating technologies, showing that the concept works in real-world settings.

What This Means for Careers and Training

As floating wind becomes more common, the skills needed to build, operate, and maintain turbines will evolve. Fixed-bottom wind already relies heavily on safety and technical training, including courses like GWO Basic Safety Training (BST) and Basic Technical Training (BTT).

Floating systems introduce new technical areas, such as:

• Mooring and anchoring

• Cable management in dynamic environments

• Towing and marine logistics

• Remote monitoring of platform movement

If you work in training, maintenance, or recruitment, expect to see increased demand for new competencies in these areas. The ability to work across both fixed and floating systems will be an advantage.

Final Thoughts

Floating and fixed offshore turbines serve the same purpose, but they operate in different ways and suit different environments. Fixed-bottom turbines are ideal for shallow waters and have a proven track record. Floating turbines are the next frontier, opening up deeper waters with stronger wind potential.

The choice between the two depends on location, water depth, cost, and available infrastructure. Both technologies are critical to the future of offshore wind.

For anyone involved in the industry, from engineers to technicians and training providers, understanding the differences helps you make better decisions, deliver better outcomes, and prepare for the changes ahead.