The Automatic *Tension Buoy*

Tension Buoy is an automatic solution for floating solar systems installed on sites with large water level variations. The Tension Buoy system maintains a constant system position by adjusting the mooring line length according to the water level. 

How does *Tension Buoy* work?

The mooring chain runs over a winch that is integrated on top of the buoy. As the water level changes, the winch adjusts the length of the chain correspondingly to maintain desired mooring line tension, this winch can be mounted temporarily for mooring tension adjustment during installation or installed permanently to follow the water variations during operation of the FPV installation. 

The chain is fed from underneath the buoy, through the centre, over the gypsy and down through the centre again. Leftover chain is left hanging freely. 

Tension Buoy Risør (2)

The Potential of Tension Buoy

The Tension Buoy represents a bold step forward in unlocking the latent potential of reservoirs behind hydropower dams. Its self-adjusting anchoring system adapts naturally to shifting water levels, ensuring floating solar and hybrid installations remain secure in all conditions. In doing so, it transforms challenging water bodies into productive assets, weaving new streams of clean energy across surfaces once considered impractical.

When paired with existing hydro infrastructure, the Tension Buoy becomes a bridge to hybrid energy systems that offer greater stability and flexibility. Solar power can supplement hydropower during bright hours or dry periods, while dams continue supplying baseload where needed. Together, they forge a more resilient, efficient energy ecosystem,one that revitalises existing assets and supports the global shift towards sustainable power.

Developed To Maintain Constant Tension Regardless Of Water Level

Our tension buoy has been developed on the back of strong engineering and maritime heritage and leveraging the renewable eco-system of the Fred. Olsen related companies.

Designed for Diverse Environments

Hydro dams are powerful yet dynamic environments. Rapid fluctuations in water level demand mooring solutions that adapt without intervention. Our Tension Buoy rises to this challenge, maintaining perfect tension across all anchoring points and enabling hybrid operation with floating solar panels. By combining hydro with our floating solar platform design, operators can optimise energy generation throughout the day while minimising stress on infrastructure reducing operational costs.

From high water in spring to low levels in late summer, lakes require adaptable technology. The buoy keeps tension balanced, protecting floating solar platforms from stress and misalignment. By responding automatically, it reduces maintenance demands and guarantees consistent clean energy production year-round.

BRIZO Hydroelectric Dam Camera01
Tension Buoy In Action

News

Tension Buoy installed in Risør, Norway
Oct 07, 2025

Introducing Tension Buoy: Unlocking Floating Solar and Hydro Power Potential

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From the left: Per Arvid Holth, Andreas Buvarp Aardal, Geir Grimsrud (FO1848). Sille Grjotheim, Hans Kristian Danielsen, Anne Lene Haukanes Hopstad, Kimon Argyriadis (DNV). Fred. Olsen.
Oct 31, 2024

BRUNEL Floating Foundation Completes DNV Basic Design Certification

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BRIZO, pilot in Risør
Feb 01, 2024

NEWS UPDATE: Fred. Olsen 1848 has deployed the Floating PV Technology BRIZO in Risør, Norway

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