Under a research project called Blue Pilot a new type of pile driver has been developed by Dutch company Fistucca BV.

The device is predicted to significantly reduce underwater noise and potentially reduce the fatigue damage to the driven pile by up to 90%. The Blue Hammer concept is being tested by full scale trials driving a monopile this summer supported by Van Oord and other industry partners. Funding for the trials has come from a variety of industry partners with the Netherlands Enterprise Agency contributing €2.5 million.

The pile driver consists of a large water tank that contains an open combustion chamber where gas combustion accelerates a large column of water. As the column of water falls back to the bottom of the water tank it transfers its deceleration energy to driving the pile. As this deceleration takes place over a longer period of time than with hydraulic systems the pile driving is both quieter and gentler.

During earlier pile driving trials the Dutch research institute TNO has measured underwater noise levels conducted by Fistucca on a test pile, during which the Blue Hammer device demonstrated that very low noise levels can be achieved. All underwater sound levels measured during these tests were far below the most stringent industry limits that currently apply in German waters, according to Fistuca. In order to protect marine wildlife, strict rules apply to the offshore construction noise and the cost of reducing pile driving noise can represent up to 15% of the installation costs.

Jasper Winkes, Director of Fistucca BV: “Given the conditions under which we measured these very low noise levels, we expect to exceed noise reductions of 20 decibels on the SEL values, when compared to conventional hydraulic hammers. This would allow contractors to save millions of euros in noise mitigation, while reducing installation risks.”

It is estimated that this Blue Hammer technology could save up to €40 million during the lifetime of a 720MW offshore wind farm which could significantly reduce the cost of the electricity produced. The reduction in fatigue stresses could lead to transition piece free designs of offshore wind farm columns. Fistucca BV is a spin off company from the University Technology in Eindoven.

By Dag Pike