Large Diameter Drilling (LDD), a specialist marine drilling and grouting contractor, and a product and service line brand in the foundations and cables segment of marine energy and infrastructure services group Acteon, has signed a contract to deliver grouting services for DEME Offshore’s installation of foundations at the Saint-Nazaire wind farm off the coast of the Guérande Peninsula, France. It will be the world’s first wind farm to use drilled XL-monopile foundations and it will consist of 80 GE Haliade 150-6MW wind turbines.
LDD will provide skilled personnel and services for grouting the drilled monopiles in position and the transition pieces to monopile connections using equipment from its Core Grouting branded service. The scope involves grouting monopiles into drilled rock sockets using a high-strength grout followed by grouting the transition pieces to the monopiles using an ultra-high-strength grout. To support these operations, LDD has developed bespoke grout mixing and pumping equipment to deliver mixed grout to the drilled rock sockets at a rate of 100 m3/h. The equipment is designed to operate primarily using bulk grout supplied from large material silos, which are also being fabricated for this project.
“The new equipment can mix and pump bulk-supplied and bag-supplied grout,” said Peter McElligott, business development engineer, LDD. “Traditionally, different types of equipment would be required to do both scopes, but, in this case, we can do both with the same equipment, which will optimise operations. Furthermore, the output of 100 m3/h reduces the vessel time required to complete the foundations. This is a step change from what is currently available on the market and one that will improve the efficiency of installing large quantities of high-strength grout.”
The early engagement was the key to the contract award. “Acteon and LDD have formed a highly collaborative relationship with DEME Offshore. We worked together to look at different ways for meeting the 100-m3/h grout delivery rate requirement. There was no suitable equipment available on the market, so our engineers put together conceptual designs that we presented to DEME Offshore,” said Ivan Harnett, renewables market lead, Acteon, “LDD already has a successful track record of working with DEME Offshore. In 2019, they completed the Belgian SeaMade offshore wind farm grouting project, so this award further strengthens our relationship.”
The contract was signed in July 2020 by Core Grouting and was novated to LDD on 1 November 2020 when Core Grouting’s employees, assets and contracts merged with LDD to form part of Acteon’s foundations and cables business segment. Core Grouting remains a product and service line brand and retain its team in Cork, Ireland, but now trades as Large Diameter Drilling Ltd.