The Challenge
When Kent needed specialised geotechnical expertise for EnBW & BP’s Mona & Morgan Offshore Wind Farm in the Irish Sea, they turned to Ternan Energy. The project required sophisticated foundation design for 18MW and 20MW Wind Turbine Generators (WTGs), with complex soil conditions presenting particular challenges. Special consideration had to be given to complex soil layering, high fines soils, and the influence of cyclic loading—all critical factors that would impact the ultimate success of these massive structures.
Why Ternan?
Ternan Energy brought the perfect combination of resources and expertise to this crucial project:
- Regional expertise: Extensive experience in the Celtic Sea region, with deep familiarity of the expected ground and geotechnical complexities
- Technical capabilities: Mastery of Finite Element Analysis (FEA) using PLAXIS 3D software
- Industry reputation: Recognised as an experienced offshore geoscience consultancy with specific expertise in offshore wind foundation design
The Solution
Ternan’s team adopted a strategic, phased approach to tackle this complex design challenge. The process began with initial suction bucket sizing using analytical methods aligned with Offshore Wind Accelerator (OWA) design guidelines, which provided reasonable estimations of the required dimensions.
This preliminary work enabled Kent’s structural team to begin designing the jacket structure with confidence, while Ternan’s engineers proceeded with more sophisticated analysis. The team then validated these initial designs through 2D modelling before conducting detailed 3D FEA modelling—a significantly more time-consuming process due to model run times.
For both the 20MW and 18MW designs, Ternan provided:
- Initial analytical sizing of suction buckets
- High-level stiffness matrices to support parallel steel jacket design
- Early-stage installation assessments to confirm bucket geometries were installable
- Comprehensive FEA modelling to verify designs and produce soil stiffness matrices
- Suction installation assessments using analytical methods with special considerations for layered soil profiles
Overcoming Installation Challenges
A key consideration in the project was the shallow water depth at the site, which significantly affected installation methodology. Ternan’s engineers calculated allowable underpressures and compared them against the cavitation limit—which largely dictated installation refusal conditions due to these shallow water depths. The team’s expertise in handling layered soil profiles was particularly valuable, as these introduce significant complexities due to the changes in flow mechanics that occur within different soil layers.
The Results
Ternan’s work enabled the successful completion of the Front End Engineering Design (FEED) for jacket foundations—a crucial milestone for the Mona and Morgan Offshore Wind Farm Projects. This comprehensive engineering support:
- Informed crucial future project decisions
- Provided data for accurate cost modelling
- Enabled the design to progress to the final detailed design phase
- Supported EnBW & BP in submitting their consenting applications for construction
Client Testimonial
“Kent have worked with Ternan Energy on several projects now. They have consistently shown their ability to manage the project scope of work they were required to deliver, including great responsiveness every time it was required and providing clear and proactive communication to manage expectations and deliveries.”
— Nico Weider, Principal Project Manager, Kent
The Ternan Advantage
This project demonstrates why Ternan Energy is a leading independent marine geoscience consultancy for offshore wind development. Their approach integrates cutting-edge technical knowledge with practical experience and a collaborative mindset. By understanding both the geotechnical complexities and the wider project needs, Ternan delivered solutions that enabled their client to progress with confidence.
Looking Forward
At Ternan Energy, integrity, independence, and innovation form the foundation of everything we do. Our 100% employee-owned structure ensures we provide unbiased, client-focused solutions without external influences. We take pride in our ability to innovate—finding creative solutions to complex technical challenges while maintaining the highest standards of technical excellence.
Whether you’re dealing with complex soil conditions, challenging installation environments, or need support throughout your marine infrastructure project lifecycle, Ternan brings the expertise, independence, and innovative thinking needed to deliver exceptional results.
Looking for expert marine geoscience support for your next project?
Contact James Deacon, Geotechnical Manager: james.deacon@ternan-energy.com