NSTA Decarbonisation of the North Sea Project - Main-Hub & Sub-Hub Layout

Katoni completed a study into Decarbonisation of the North Sea on behalf of the North Sea Transition Authority, the project's aim was to study & develop a design for an offshore electrical power network that would act as an interface between distributed sources of renewable power & Oil & gas assets. An integral part of this required Katoni to develop a concept for Main-Hub & Sub-Hub infrastructure.

Initially a concept analysis was carried out to determine the most suitable marine solution for facilitating the requirements for the Main Hub & Sub Hubs. This involved reviewing Fixed Assets, Ship Shaped FPSO’s, Sevan type FPSO, Jack-ups & Semi-Submersible Platforms. From this analysis the Sevan type FPSO was recommended.

The Layout philosophy applied to both the Main-Hub & Sub-Hub design adhered to the general principles of safe, operable & maintainable facilities while aligning with relative recommended practices & guidelines.

Primary considerations for the main-hub and sub-hub designs included Safety, Weight Control, Operability, Maintenance, Constructability, Economics and Balance.

The Main-Hub

The Main-Hub utilises a Sevan FPSO with a 104m hull diameter providing a scalable, pre-assembled modular approach with a repeatable design that allows for future expansion. The Main-Hub is designed as a maned installation incorporating Power generation, Transformation, Storage, Controls & Distribution capabilities.

Figure 2 – The main-hub proposed layout in a General Arrangement style drawing.

The Sub-Hub

The Sub-Hub uses a similar philosophy of the Main-Hub but on a small FPSO-60m hull diameter. The Sub-hub is a Normally Unmanned Installation (NUI) capable of receiving bulk power from the Main Hub & providing the final transformation & power regulation to provide suitable input to a number of individual Oil & Gas installations.

Figure 3 and 4 – The sub-hub proposaed layout as a £D model and in a General Arrangement style drawing.

Additionally, during the layout of the Main-Hub & Sub-Hubs and in parallel with the characteristic of Equipment, consideration was given to standardisation in design, modularity (PAUs), pancaked structure, & E-house.