Hollandse Kust Zuid Offshore Wind Farm Grid Connection, The Netherlands

Enabling the transition to a renewable energy future

As the transmission system operator in the Netherlands and North Germany, one of TenneT’s current projects is the high voltage grid connection for the Hollandse Kust Zuid (HKZ) offshore wind farm, made up of two 700MW circuits. The offshore connections rely on two 66kv to 220kv transformer platforms known as Alpha and Beta.

Key information

North Sea
Date started:
Completion date:
Client type:
Natural resources
Main services:
advisory, controls and performance

Complex delivery

TenneT’s Alpha and Beta 700MW transformer platforms are components of the critical infrastructure needed to connect energy generated from the HKZ offshore wind farm to land.

Maintaining programme milestones to support wind farm development and installation is a huge challenge. This is due to the complex requirements and risks involved when building and installing large infrastructure and electrical equipment at sea.

Major threats to progress include low productivity during fabrication, and quality issues that could potentially delay connection of the wind farm to the grid.

Concern that the COVID-19 pandemic was impacting fabrication of the transformer platform topsides, and critically, their forecast completion date, TenneT commissioned us to provide a project performance assurance service including progress monitoring, progress measurement and verification.

The services included project management and project controls advice during the fabrication phase.

Critical for TenneT was assurance that the fabrication schedule, including onshore testing and commissioning, was on track to meet the project’s Ready For Sail Away (RFSA) date, and all subsequent transportation and installation commitments.

Meeting critical construction milestones

Collaborating with TenneT’s Engineer, Procure, Construct and Install (EPCI) contractor, we rapidly mobilised and led an independent Joint Task Force comprising planning, project controls and quantity surveying specialists at the fabrication site in Dubai.

At the Dubai Drydocks, we delivered our industry best practice solutions for construction progress measurement.

Deploying our quantity, weight and cost assurance service, QuanTTum, we were able to analyse and measure the quantities required for the topside and jacket from Alpha and Beta’s 3D models, enabling the development of an accurate bill of quantities and creation of a schedule and progress measurement system (PMS) built on measured quantities.

The PMS provided a clear and transparent audit trail of installed quantities and accurate, actual weekly progress, providing assurance, or adjustment where necessary, of the forecast completion, sail-away, transportation and installation dates.

Power BI was used to present dashboard status updates on progress, providing clarity and a single source of truth for senior management.

We also used the Matterport visual image capture and measurement tool to maintain an accurate status of offshore fabrication completion and allow progress of the offshore hook up and commissioning (HUC) phase to be monitored remotely.

Crossing borders, connecting countries

TenneT’s key objective is to deliver a secure and continuous supply of electricity. The high-voltage grid is the backbone of the electricity supply system, connecting electricity producers to consumers, connecting and integrating electricity markets.

We continue to work closely with TenneT to identify opportunities to improve project set up and delivery of future grid connection developments.

Joris Engelen, Project Lead Platform, TenneT said:

“TenneT is committed to facilitate Netherlands ambitions for offshore wind. It has been a challenging year and Turner & Townsend has supported us in maintaining control and meeting the programme milestones of the critical infrastructure required to connect HKZ.”

For further information contact:

Andrea Brambilla
Lead Consultant