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Conference programme 

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Poster session

Lead Session Chair:
Stephan Barth, Managing Director, ForWind - Center for Wind Energy Research, Germany
Matthew Bleasdale OWLC, United Kingdom
Matthew Bleasdale (1) F P
(1) OWLC, Kirby Muxloe, United Kingdom

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Presenter's biography

Biographies are supplied directly by presenters at OFFSHORE 2015 and are published here unedited

Matt has significant offshore construction experience and almost a decade in offshore wind. He started his offshore career in subsea cables and oil & gas construction. In offshore wind he managed the cable contacts for London Array prior to taking a role at The Crown Estate. His offshore construction knowledge led to a risk and sensitivity analysis of the offshore wind business model which identified the innovation that is the Gravity Tripod. Matt left TCE in December 2013 and currently consults on cable installation as well as risk and cost reduction, while directing the development of the Gravity Tripod.


Cost reduction through innovation - structural analysis of the gravity tripod and a path to a new offshore wind business model.


The Gravity Tripod is an innovative concrete gravity base structure designed to reduce the cost of offshore wind. This presentation will introduce the results of the initial independent engineering review as well as what implications the concept has for cost reduction. It will present the results of the unpublished concept design review (validating the structural design) as well as the research into the offshore wind business model, and the cost/risk analysis of it, that identified the concept.


As a hybrid concrete jacket/gravity base design, the Gravity Tripod benefits from componentised production and simplified installation. The design offers significant cost benefit in CAPEX, construction stage finance, OPEX and cost of capital. The distributed manufacturing process enables rapid, space efficient, low cost, scalable assembly. The structure aids installation by limiting the amount of site preparation required and increasing the utilisation of high capacity, low risk vessels for fast installation. The long asset life, low risk nature of the concept reduces the operational cost of the structure and aims to attract institutional investment to let the cost of capital.

Main body of abstract

The concept design review was conducted by Ramboll and it analysed the structure when subjected to theoretical wave and turbine loads, for a 14m wave and an 8MW turbine. The structure was fixed to the seabed and exposed to the wave from three different angles at the same time as the turbine load. The modelling analysed the static and dynamic loads upon the structure, the results of this defined the dimensioning of the struts and base plate. This presentation will detail the results of that analysis and set out the path for continued development of the concept.

The innovation was identified through a cost and risk sensitivity analysis of the levelised cost of energy. By understanding the key technical issues underpinning the cost structure of offshore wind it was possible to a address those root causes to tackle the reason for high cost of electricity. This presentation will go into that analysis explaining the way in which an indepth understanding of the engineering behind offshore wind can lead to cost reduction initiatives.


The Gravity Tripod is designed for cost reduction, the innovation having been identified through analysing the sensitivities and risks on the critical path and the other cost centres of the offshore wind business model. The presentation will touch on aspects of that levelised cost of energy analysis and the identified cost and risk benefits of the concept.

Learning objectives
This presentation will inform the audience about the key cost and risk sensitivities of the offshore wind business model, how innovation can affect those issues and how structural analysis of those innovation can validate the concepts.