Installation of offshore structures

NGI's experience with the design and supply of installation monitoring systems dates back to 1975 when the gigantic concrete gravity base platforms were installed in the North Sea.

For the offshore wind industry, NGI has developed and provided novel metrology systems for pre-piling by means of instrumented piling templates. The tight installation tolerances and extreme conditions during pile driving required novel and robust monitoring solutions.

As "Prototypes are our standard," we can offer customized real-time monitoring solutions for many specific applications, including anchor installation for moored Offshore Wind Turbine floaters. The aim is to provide real-time monitoring control of the installation without needing ROV or Diver intervention.

The real-time data presentation is customized dependent on the type of installation. The data acquisition system architecture is flexible, enabling data input from other sensor systems and data sharing. With an internet connection to shore, live installation data can be streamed to a land server, and the field installation can be followed up from the office.

The installation services from NGI may also include geotechnical assistance during the operations in the field.

Project examples

Pre-piling template instrumentation

• 2009 Alpha Ventus windfarm, pre-piling frame for 6 quattropod jackets (Norwind/Geosea)
• 2010 Ormonde windfarm, pre-piling frame for 42 quattropod jackets (Geosea)
• 2011 Thornton windfarm, pre-piling frame for 49 quattropod jackets (Geosea)
• 2011 Borkum west windfarm, pre-piling frame for 41 tripod jackets (Geosea)
• 2013 Baltic II windfarm, instrumentation for pre-piling frame for 41 tripod jackets (Hochtief/Geosea)
• 2014 Wikinger subsea pile load test, piling frame (Bilfinger/Iberdrola)
• 2019 Greater Changhua Offshore wind farm, subsea pile load test (Per Aarsleff AS/Ørsted)
• 2021 Delivery of unique instrumentation for 2 pre-piling templates in China (HXOES Jiangsu Huaxicun Offshore Eng. Service)

Suction Bucket Jacket installations for offshore wind farms

• 2019 Borkum Riffgrund 2 wind farm, XX jackets installed (Ørsted)
• 2023 Seagreen Offshore Wind development.Offshore Scotland, 114 jackets installed (Saipem)
• …………………….
• …………………….

Reliable foundation installation

Installing suction caissons or "bucket" foundations is fast but requires understanding the different geotechnical processes that apply during suction penetration. The variable soil conditions often met at offshore sites have brought new insight into feasible installation, and the limits have been expanded.

We have been involved in several installations of bucket foundations in difficult soil conditions. The most important factors to ensure the successful installation of such foundations are sufficient pumping capacity and a reliable monitoring control system.

NGI and FRAMO operate pump skid systems with integrated instrumentation especially developed for the offshore wind industry. The pump skids have combined functionality to enable installation without ROV intervention.

The combination of adequate installation equipment and geotechnical understanding ensures reliable foundation installation services for the offshore industry.