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Delegates are invited to meet and discuss with the poster presenters in this topic directly after the session 'Floating wind turbines' taking place on Wednesday, 12 March 2014 at 16:30 -18:00. The meet-the-authors will take place in the poster area.

LUCIA MENESES Environmental Hydraulics Institute "IH Cantabria", Spain
Co-authors:
LUCIA MENESES (1) F P RAUL GUANCHE (1) CESAR VIDAL (1) IÑIGO LOSADA (1)
(1) Environmental Hydraulics Institute , Santander, Spain

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Abstract

Innovative multi-use offshore farm at atlantic ocean site

Introduction

European oceans will be subject to massive developments of marine infraestructure on the next decades. Massive offshore wind farms are being constructed and new prototypes for marine renewable energy are tested in order to meet the objetives for renewable energy, set by the EU strategies.
Meanwhile, offshore facilities are required to explore the potential of marine aquaculture in European waters and increasingly offshore platforms are needed to address te demands of maritime transport.
Hence, offshore platforms that combine multiple functions within the same infrastructure offer significant beneficts in terms of economics, optimizing spatial planning and reducing the impact on the environment.


Approach

This work has been developed in the framework of the European project MERMAID. The main aim of the MERMAID project is to develop concepts for a next generation offshore platforms for multi-use of ocean space for energy extraction, aquaculture amd platform related transport. The project does not envisage building a new platform but aims at exmining different concepts, such as a combination of structures or complete new strucures on representative sites under different conditions.
Therefore, the present study is focused on the design a innovative multi-use offshore farm at Atlantic ocean site. The Atlantic Ocean has been clasiffied as a typical deep water site, the site selected is the Cantabrian Offshore Site, located in Spain, offshore the region of Cantabria.
The final aim of this work is the design an innovative technology that integrate concepts for marine renewable energy and other offshore industries like aquaculture. So, to to achieve this purpose, is necessary to carry out the next partial goals:
• Analysis of offshore technology for deep and ultradeep waters: foundations, mooring and anchoring systems,...
• Design parameters and met-ocean conditions of the site.
• Energy converter analysis for waves, wind and currents.
• Numerical and physical analysis.
• Multi-use platform site integration in a farm design: Different uses share the same area, or Different devices share the same platform and sea area.
Hence, based on the work and the conclusions achieved in terms of best wave and wind technology combination, structure recommendation design, the final technology integration and optimization will be studied. And based on the calibrated numerical models the final integration will be analyzed.


Main body of abstract

SITE DESCRIPTION: CANTABRIAN OFFSHORE SITE
There Cantabrian Offshore Site (COS) is located offshore the city of Santander, Cantabria, Spain. This site is well suited to explore floating wind turbines and wave energy concepts. Wind conditions will be assessed thanks to a 90 meters height floating meteorological mast located 5 km offshore, deployed at 50 m water depth by IDERMAR. Wave and current conditions has been assessed by a wave rider located at 40 m water depth, 3 km offshore from the shoreline. This device has been deployed by the Regional Ministry of Environmental and Water, and data management is carried out by the University of Cantabria. Instrumental information will be combined with the numerical models to determine meteocean conditions in the site. The Cantabrian Offshore Site (COS) will be fully monitored thanks to existing operational systems for wind, waves and currents.


Figure 1 shows the IDERMAR III floating mast site in the Cantabrian Offshore Site (COS) [1].

Figure 1. IDERMAR floating meteorological mast located 5 km offshore the Santander coast.
Among other reasons, the Cantabrian Offshore Site (COS) is of high interest because its close location to large port facilities, as well as shipyards and other industries. Information on environmental issues, as well as, socio-economic aspects is already in available. Figure 2 shows the main facilites near to the Cantabrian Offshore Site (COS).


Figure 2. Facilities near Cantabrian Offshore Site.

Resource Analysis: Wind and Waves

60 years of hourly sea state parameters at the Cantabrian Offshore Site have been analysed to characterize the wave conditions and wave energy power. Figure 3 shows the yerarly average of wave energy resource at COS, being the avalaible power 25-30 kw/m [2].


Figure 3. Wave energy resource. Yearly average.

For the wind energy resource it has been analyzed 62 years of hourly wind parameters. The wind databases is HR-SeaWind from The Environmental Hydraulics Institute of the University of Cantabria. Figure 1. IDERMAR floating meteorological mast located 5 km offshore the Santander coast. Figure 3 shows the year average of wind intensity at COS.


Figure 4. Wind energy resource (W/m2). Yearly average.

CONCEP DESIGN
Due to the environmental site conditions, the main resources of this area are wind and waves, so the renewable devices that it has been studied are wind offshore floating platforms and wave energy converters.
The analysis of the existing energy conversion devices is focused on their strengths and weakness for conversion efficiency, survival capabilities and suitability to be combined with other energy resource devices or aquaculture.
In this study it has reviewed the state of the art, and select a set of offshore concepts. The selected concepts will be pre-designed and tested at UC facilites. The information obtained of this analysis, is used to analyze the compatibility of different energy devices for integration on multipurpose platforms or in a multipurpose farms. Different multi-use concepts considered are showed in Figure 5.


Figure 5. Preliminary design of multipurpose concepts. a) Wind + Waves + Aquaculture. b) Waves + Aquaculture. c) Wind + Waves. d) Wind + Aquaculture

The final objetive of this work is to provide a design of the layout of the farm at the Cantabrian Offshore Site.

Conclusion

This work will document the importance to find solutions that allow a sustainable use of the resources and space of ours oceans. It summarices a deep analysis of all stages that conform a design methodology for multi-use platforms. At the begining it has characterised the Cantabrian Offshore Site, Metocean data assessments conclude that COS is a excellent place to install energy conversion devices, especially wind and waves converters. Next, the review of different offshore technologies for deep and ultra-deep waters, with the ultimate goal of gaining knowledge for the selection of the optimal technology for MUP development, adds value to the work is doing.
Then, the main part of the work, the design of a device for integration on multipurpose platforms or in a multipurpose farms, include the analysis of different alternatives, moreover, the detail analysis of the multi-use farm.
In order to ensure the sucess of the design was aimed at taking into account the socio-ecoómicos and impacts associated with the installation of a multi-use farm in the Cantabrian Offshore Site. The oportunities asociated to a multi-use farm intalation at Cantabria, generating a lot of benefict for the region, and the balance will be entirely positive. The capability to increase employment and open new markets will be essential in the development plan of the region.
Future work should therfore included a physical modelling of the final design to calibrate de numerical model and to ensure the structural behavior of the design.


ACKNOWLEDGMENT
This work has been part of a research project MERMAID (“Innovative Multi-purpose off-shore platforms: planning, design and operation” Grant Agreement no.: 288710. Seventh Framework Programme Theme [OCEAN.2011-1]). The autors would like to thank to the European Community (EC) for its economical support in the development of this project.



Learning objectives
The aim of present work is develop concepts for the next generation of offshore platforms which can be used for multiple purposes. This work is the beginning of a new stage towards sustainable use of the oceans uses.

Hence, offshore platforms that combine multiple functions within the same infrastructure offer significant economical and environmental benefits.


References
[1] Guanche, R., Vidal, C., Piedra, A., Losada, I. (2011). "IDERMAR METEO. Offshore wind assessment at high and very high water depths". OCEANS 2011 IEEE - Spain. art. no. 6003525.

[2] www.enola.ihcantabria.es