TenneT Germany becomes Development Sponsor of Frequensea Decommissioning Tool 

Frequensea Decommissioning Tool during testing at Deltares

TenneT Germany is supporting the Frequensea Decommissioning Tool as a new Development Sponsor, helping to advance the technology towards offshore deployment. 

The Frequensea Decommissioning Tool is being developed to support the efficient recovery of subsea cables while reducing disturbance to the seabed. TenneT Germany’s involvement brings the practical perspective of an offshore transmission system operator with extensive experience in subsea power cable infrastructure.

Upon successful completion of the testing programme at Deltares, TenneT Germany will evaluate the tool’s potential for the future decommissioning of offshore cables in the North Sea. 

TenneT Germany joins two existing Development Sponsors: offshore energy contractor DEME and cable handling systems specialist Subsea Cable Assets (SCA). Together, the three sponsors bring valuable perspectives from grid operation, offshore installation and subsea cable activities to the further development of the technology. 

With TenneT Germany becoming a Development Sponsor, Frequensea takes another important step towards qualifying the Decommissioning Tool for future offshore deployment and exploring its potential to support the efficient recovery of subsea power cables in the North Sea. 

Phase Two Testing Introduces Horizontal Pull Tests for Frequensea Decommissioning Tool 

Frequensea Decommissioning Tool during phase 2 testing at the Deltares test basin

The testing programme for the Frequensea Decommissioning Tool has entered its second phase, building on the successful first series of tests and expanding the scope of the programme. 

For this new phase, the test site has been prepared for a new series of tests. The existing test programme from phase one will be extended with new positions and different configurations of the test set-up, providing further data on the tool’s performance under varying test conditions. 

In addition, phase two introduces horizontal pull testing, with the tool tested in both horizontal and vertical orientations. During these tests, the tool is pulled horizontally through the soil to evaluate its behaviour and performance in both orientations. This adds a new element to the testing programme and further expands the data being gathered during phase two. 

The Frequensea Decommissioning Tool is designed for the environmentally responsible removal of subsea cables, umbilicals and pipelines. The tool uses patented vibration-induced fluidisation technology to efficiently extract buried assets while minimising disturbance to the surrounding seabed and marine environment. 

Testing is progressing well, with more test runs to follow as phase two continues.

Frequensea Development Sponsor Day Features Full Scale Recovery & Burial Test

Frequensea Development Partner Day with successful burial and recovery demonstration of the Frequensea subsea cable and pipeline recovery technology.

On Friday, 17 July, the Frequensea Development Sponsor Day took place at Deltares. During the event, Frequensea successfully  demonstrated the Recovery & Burial capabilities of its Decommissioning Tool. 

The partner event opened with presentations on the progress of the tool development, the upcoming test programme and the project roadmap. The programme then continued with a laboratory tour, where the live Recovery & Burial Demonstration showed the capabilities of the Frequensea Decommissioning Tool and its patented vibration-induced fluidisation technology under realistic operating conditions. The demonstration was attended by representatives of early development sponsors DEME and SCA. 

Following the demonstration, guests concluded the Frequensea Development Sponsor Day with networking refreshments,  providing an opportunity to discuss the progress of the project and the upcoming phases of the Frequensea qualification programme. 

This project is supported by the Topsector Energie / Energy Innovation NL programme through a subsidy provided by the Netherlands Enterprise Agency (RVO). 

Frequensea Decommissioning Tool completes Factory Acceptance Testing and arrives at Deltares 

Frequensea's decommissioning tool with integrated vibration motors suspended above the Deltares tes basin following successful factory acceptance testing, ready for the next phase of validation

The Frequensea Decommissioning Tool has reached another important milestone in its development. The integrated vibration motor assembly (vibration module) successfully completed factory acceptance testing at steel construction specialist J. van Belzen, where functional and watertightness tests confirmed its performance and integrity. 

The vibration module has now been delivered to Deltares, where the next phase of the qualification programme is about to begin. 

At Deltares, the vibration module will undergo a series of sweep tests under controlled laboratory conditions. During these tests, the assembly will be placed under water beneath a layer of sand in a dedicated test basin, replicating subsea buried conditions. By gradually varying the operating frequency of the vibration motors, the test team will determine the optimum frequency at which soil liquefaction occurs. These results will form the basis for the entire testing programme at Deltares this summer. 

Once qualified, the Frequensea Decommissioning Tool will utilise its patented vibration-induced fluidization technology to provide the offshore industry with an efficient and environmentally responsible solution for the removal of redundant subsea cables and pipelines. 

By minimising disturbance to the surrounding seabed, the technology supports the growing need for sustainable offshore decommissioning. 

Frequensea Decommissioning Tool Reaches Key Fabrication Milestone

Vibration motors undergoing initial commissioning tests, powered by variable frequency drives (VFDs) prior to installation in the Frequensea Decommissioning Tool

The development of the Frequensea Decommissioning Tool is advancing rapidly, with fabrication, assembly and integration activities now in full swing.

Major structural components and subsystems are currently being assembled and integrated at Van Belzen, a specialist in steel construction. The Drive and Control systems are being prepared by EPMC Europe. This week marked an important milestone as the vibrating motors were successfully powered by the VFD for the first time, ready for installation into their steel housing.

Over the coming weeks, the project team will carry out pre-run and acceptance testing to verify functionality, subsystem integration and watertightness.

The Frequensea Decommissioning Tool was designed by sister company Enersea, leveraging its extensive offshore engineering and subsea expertise. Frequensea B.V. is responsible for the development, qualification and future commercialisation of the technology.

Designed for the environmentally responsible removal of subsea cables, umbilicals and pipelines, the Frequensea Decommissioning Tool utilises patented vibration-induced fluidisation technology to efficiently extract buried assets while minimising disturbance to the surrounding seabed and marine environment.

Further updates will follow soon as the project progresses through testing and development.

Frequensea would like to acknowledge the valuable support of its early development partners DEME and SCA as well as the Topsector Energie / Energy Innovation NL subsidy provided by Netherlands Enterprise Agency (RVO).

Key Fabrication Milestone for the Frequensea Decommissioning Tool; the vibration motors have been successfully powered up and tested for the first time.

Frequensea full-scale test programme kicks off at Deltares

Kick-off meeting Frequensea testing @Deltares

On 4 February, the kick-off meeting for the full-scale test programme of the Frequensea decommissioning tool took place at Deltares in Delft. The event brought together 22 interested development partners, marking the official launch of the testing phase.

Dieter Korndorffer, Co-founder and Managing Director of Frequensea, presented the upcoming test programme and its objectives. Pieter de Man, Project Manager at Frequensea, outlined the company’s development roadmap, while Deltares provided a detailed presentation of the planned testing activities.

The tests will be carried out using the latest prototype of the Frequensea decommissioning tool and are designed to validate performance, reliability, and operational readiness under controlled conditions.

Following the presentations, participants were given a guided tour of the Deltares testing facilities, where the programme will be conducted.

The kick-off meeting marked an important milestone for Frequensea and its partners, setting the stage for the next phase in the development and qualification of the decommissioning tool.

Frequensea gratefully acknowledges the support of early development partners DEME and SCA and the Topsector Energy subsidy from the Ministry of Climate and Green Growth.

Frequensea winner Offshore Energy Innovation Award!

Frequensea winner Offshore Energy Innovation Award

Frequensea was announced as the winner of the Innovation Award during the second day (26 November) of the Offshore Energy Exhibition & Conference (OEEC25).

In his innovation pitch, Dieter Korndorffer, Managing Director and co-founder of Frequensea, highlighted the growing need for environmentally responsible cable decommissioning as the first offshore wind farms approach the end of their operational lifecycles.

Frequensea’s decommissioning tool, currently under development, is designed to enable this process to be carried out safely, efficiently, and in a more cost-effective manner.

Speaking on The Stage in front of the audience, Dieter expressed his enthusiasm and appreciation for the recognition, stating that this acknowledgment reinforces Frequensea’s position as a potential game changer in offshore decommissioning.

Busy Frequensea stand at OEEC25

Frequensea stand at Offshore Energy 25

The Offshore Energy Exhibition & Conference 2025 (OEEC25) at the RAI Amsterdam is in full swing. The Frequensea stand (no. 2.103) in the Innovators Area has been well attended by potential clients interested in the patented Frequensea technology.

On 25 November, the first day of the exhibition, Dieter Korndorffer, Managing Director of Frequensea, delivered an Innovation Pitch at the Square podium, which was received enthusiastically by both the audience and the moderator.

Today, from 14:00 to 15:00, Dieter will represent Frequensea as one of seven finalists by presenting the Frequensea decommissioning tool at the Innovation Award Show on The Stage in Hall 1.

With the jury questioning the finalists, this session promises to be one of the most interesting parts of the programme.

Frequensea exhibits at OEEC25

Frequensea exhibits at OEEC25

Frequensea will exhibit at the Offshore Energy Exhibition & Conference 2025 (OEEC25) in the RAI Amsterdam on 25 and 26 November.

At stand 2.103 in the Innovators Area, we will be showcasing our patented vibration-assisted technology that enables safe, efficient and environmentally responsible decommissioning of subsea cables and pipelines.

We are proud to be nominated for the Offshore Energy Award – Best Innovation 2025, with Dieter Korndorffer pitching during the Innovation Award Show on day two of the conference.

Come meet our team and learn all about this groundbreaking tool!

Frequensea nominated for Best Innovation of 2025

Frequensea nominated for Best Innovation of 2025

Frequensea is proud to announce its selection as one of the seven finalists competing for the Best Innovation of 2025 award at the Offshore Energy Exhibition & Conference (OEEC).

Frequensea will present its subsea decommissioning tool during the Offshore Energy Innovation Show at podium The Stage from 14:00 to 15:00 on 26 November, the second day of OEEC.

Managing Director of Frequensea, Dieter Korndorffer, will pitch the decommissioning technology that combines controlled vibration with fluidisation to loosen and remove subsea cables and pipelines safely, efficiently and cost effective while reducing seabed disturbance.

“We are honoured to be recognised among such strong and forward-thinking innovations,” said Korndorffer. “This nomination highlights the potential impact of our technology on the offshore energy sector.”

The technology pitches of the seven finalists will be judged by an expert jury. The winner will be announced after all contestants have presented their innovation and the judges have completed their deliberation.