Carbon Trust tests 'noise-reducing' hammer

NETHERLANDS: Members of the Carbon Trust's Offshore Wind Accelerator (OWA) programme and piling technology firm Fistuca have successfully tested an installation hammer designed to reduce underwater noise and reduce fatigue damage.

Fistuca’s Blue 25M Hammer was tested off the Dutch coast in August (pic credit: The Carbon Trust)

Fistuca’s Blue 25M Hammer uses a large water tank to "provide a more energetic, but quieter blow" during installation of offshore turbine foundations.

It was tested using Van Oord’s offshore heavy lift installation vessel Svanen off the coast of the Netherlands in August

The Carbon Trust said it could also help to reduce the time crews spend offshore as well as the number of operations carried out during installation, therefore improving health and safety and lowering installation costs.

It claimed the hammer is designed to reduce underwater noise levels by up to 20 decibels and could reduce fatigue damage — the weakening of materials caused by repeatedly applied loads — during installation on the pile by nearly 90%.

This would reduce the need for underwater noise mitigation, the Carbon Trust added.

It could also enable secondary steel to be pre-welded to the monopile prior to installation, potentially facilitating designs without transition pieces.

During testing of the Blue 25M Hammer, data was recorded on underwater noise levels on both the monopile and in the surrounding area.

This will allow Fistuca to optimise the hammer for use on large-scale offshore wind farms, the Carbon Trust stated.

Through its OWA research and development (R&D) programme, the Carbon Trust aims to reduce the cost of offshore wind, making it more competitive with conventional energy generation.

It also aims to provide insights regarding industry standard and best practice health and safety requirements.

The OWA consists of E.on, EDPR, EnBW, Equinor, Ørsted, Scottish Power Renewables and Iberdrola, Shell, Sif, SSE, Van Oord and Vattenfall.

It has helped to develop lighter monopile foundations through its Pile Soil Analysis (PISA) project and to commercialise 66kV cables.

The programme is working on three-dimensional wind mapping of future project sites and has supported research into floating lidar systems and suction bucket foundations.