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Thu September 20 2018

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New pile driver aims to improve offshore wind construction

15 Mar The Carbon Trust has launched of a demonstration project to test a new type of pile driver for use in building offshore wind farms.

The Blue Pilot project is aimed at reducing the costs of offshore wind farms as well as the underwater noise generated during construction. It will deploy the Blue Hammer, a new type of pile driver developed by Fistuca, a Dutch technology company founded as a spin-off from Eindhoven University of Technology. It is anticipated that the project could enable potential lifetime savings €33m – €40m for a 720MW offshore wind farm, which is equal to a ‘levelised cost of energy’ (LCoE) reduction of €0.9-€1.2/MWh.

The work is part of the Offshore Wind Accelerator (OWA) programme. OWA partners E.ON, EnBW, Ørsted, Statoil and Vattenfall, alongside additional industry partners Fistuca, Van Oord, Shell and Sif are contributing €3.2m (£2.8m) in funding to the project. The project’s ability to impact the cost of offshore wind has led RVO, the Netherlands Enterprise Agency, to provide public subsidies of over €2.5m.

Fistuca developed the Blue Hammer back in 2011 and originally tested the concept at a smaller scale supported by Van Oord together with a subsidy from the TKI Wind op Zee, an RVO program. After a successful test of a prototype in 2016, Fistuca secured investment from Huisman Equipment and the RVO to manufacture a full-size hammer, capable of driving the largest XXL monopiles currently available in the market.

The Blue Hammer consists of a large water tank that contains an open combustion chamber. Energy for driving the pile is created with gas combustion that accelerates a large column of water. As the column of water falls back to the bottom of the water tank, it decelerates transferring the energy into the pile. The properties of water mean that this deceleration occurs over a longer time period than a conventional hydraulic hammer, providing a quieter, gentler but more energetic blow.

The Blue Hammer is predicted to reduce underwater noise levels by up to 20dB (SEL), and potentially reduce the fatigue damage during installation on the pile by up to 90%. This could not only remove the need for underwater noise mitigation, but also enable secondary steel to be pre-welded to the monopile before installation, potentially unlocking ‘transition piece free’ designs. Furthermore, by reducing the amount of time and number of operations carried out offshore, the piling method would improve health and safety and result in a significantly lower installation cost.

The Blue Pilot project aims to verify these predictions through the installation of a full-size monopile offshore, using measurement equipment and sensors to validate the predicted noise levels and fatigue damage. The tests will take place this summer and high-level findings from the study will be made publically available later that year.

In the Blue Pilot project the hammer will be tested offshore at a location in Dutch waters. Sif will provide the monopile, and Van Oord will support the installation logistics. Other industry partners will provide funding and strategic advice into the project to ensure its relevance to future commercial projects.

Fistuca founder and managing director Jasper Winkes said: “We want to help the offshore wind industry to further develop environmentally friendly installation methods and also lower the foundation costs. Therefore we are pleased that, together with the leading utilities in the world, the Blue Pilot project aims to deliver the proof that innovations can drive down the LCOE even further. Only collaboration throughout the industry will make this possible."

Rajnish Sharma, technology director, wind & low carbon solutions at Statoil, added: “Statoil is constantly seeking to reduce the environmental impact and cost of our offshore wind projects. The Blue Piling technology has the potential to be an important contributor in this work, and we look forward together with the industry to develop this new technology.”


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