This section addresses recent and current research activities in offshore wind energy. A large number of national and international R&D projects on offshore wind energy have been undertaken over the last decades and the more recent and relevant a re briefly described within this section. For convenience, the y have been arranged in the following groups :
· Resource assessment,
· Windturbines (including support structures)
· Windfarm
· Installation
· O&M
· Integrated methodologies
Further information on European funded projects is available at the CORDIS and Agores databases and projects are generally reported at the appropriate European wind energy conferences :
· European Wind Energy C o nferences [EWEC]
o Copenhagen 2001,
o Nice 1999,
o Dublin 1997,
o Gothenburg 1996.
· OWEMES Seminar (Offshore Wind Energy in Mediterranean and other European Seas):
o Rome1994,
o La Maddalena 1997,
o Siracusa 2000.
This section briefly describes research project s that have focused on d efining the resource, for purposes such as estimating energy production, predicting the loads on the wind-turbine, optimising the wind farm layout and evaluating the extent of the total offshore resource available.
Predicting offshore wind energy resources [POWER]
This European funded project was undertaken jointly by CLRC \ RAL ( lead contractor), University of East Anglia, KEMA , Ecofys and Risø under the Fourth Framework JOULE Programme, reference JO R 3980286 and was completed in the middle of 2001.
The objectives of the project were to assess offshore wind power potential in EU waters. The work involves determining the geostrophic windfrom long-term pressure fields, transforming the wind to sea level, taking account of nearshore topography using WAsP and correcting for stability effects using a Coastal Discontinuity Model.
Wind Energy Mapping using Synthetic Aperture Radar [WEMSAR]
This European funded project is being undertaken jointly by Nansen (lead Contractor), ENEA , Risø , NEG Micon and Terra Orbit under the Fifth Framework Programme, Reference ERK6 -1999-00017, and is due to be completed and in 2003.
The objective is to investigate, validate and demonstrate the potential of satellite-based synthetic aperture radar (S AR ) to map wind energy in offshore and near coastal regions for potential wind-turbines siting.
Wind resources in the Baltic Sea
This European funded project was undertaken jointly by Risø it, University of Karlsruhe, the Finnish M eteorological I nstitute, University of Keele under the Third Framework Programme, reference JOU20325 and was completed in 1996.
The objective was to describe and map the wind resources of the Baltic Sea and the Gulf of Finland and to create and test tools for siting of windturbines in coastal areas.
S tudy of O ffshore W ind E nergy in the European Community
This European funded project was undertaken jointly by Germanischer Lloyd and Garrad Hassan under the Second Framework Programme, reference J OUR00 72 and was completed in 1993.
The focus of the project was to undertake an exploratory study covering the following four tasks: the potential for offshore wind energy in Europe, experience in offshore engineering relevan t to offshore wind farms, design guidelines and consideration of combined wind and wave loading.
The National Technical University of Athens is carrying out research into wave resource modelling [1], specifically for wave energy schemes but of relevance to offshore wind projects for determining the wave climate.
Research and design tools include:
The New WAsP The goal of the project is to develop the next generation of the WAsP computer program, which should be able to handle modelling in complex terrain as well as offshore in a better manner. Two tracks will be followed, one will try to take advantage of and implement the newest technologies within the flow-modelling field and the other will develop incremental improvements to the existing code. Once the new algorithms have been developed they will be implemented in the familiar WAsP GUI (Graphical User Interface) [7] - [11]
: Zukunftsinvestitionsprogramm (FuE/ZIP)
This project (in E nglish Future Investment Programme) is being undertaken jointly by BMWi [Ministry for Economic Affairs] and BMU [Ministry of Environment Protection], is due to in 2001 and will cover :
· measurement platforms in the North Sea and Baltic Sea for wind resource assessment and ecological monitoring research:
· bird migration
· marine acoustics with respect to impact on sea mammals
· investigation on sea bed life
· investigation on impact on fish
This section briefly describes research projects that have focused on modelling the wind-turbine and the support structure. Regarding the current status of design tools, these include:
· the prediction of offshore wind regimes by analytical techniques and the monitoring of existing wind farms
· refinement and development of integrated dynamic structural models of the entire turbine and foundation system
· reliability/availability
· prediction of rotor dynamics
Recommendations f or D esign of O ffshore W ind T urbines [RECOFF]
This European funded project is being undertaken jointly by Risø (lead contractor), CRES , ECN, Garrad Hassan and Germanischer Lloyd , u nder the Fifth Framework Programme, r eference ENK5 -2000-00322 and is due to be completed at the end of 2003.
T he project aims at the provision of recommendations for a standard design of offshore wind turbines. R eadily available information will be utilised to the extent possible and where a need is identified, research and development will be performed. The recommendations will be addressed directly to the two standardisation bodies: the I nternational E lectr o t echnical Commission (IEC) and the European CENELEC.
Design M ethods for O ffshore W ind T urbines at E xposed S ites [OWTES]
This European funded project is currently being undertaken jointly by Garrad Hassan (lead contractor), AMEC Borderwind, Germanischer Lloyd, PowerGen Renewables, TUDelft and Vestas under the Fourth Framework Programme, reference JOR3980284 and is due to be completed in 2002.
The aim of this project is to improve the design methods for wind-turbines located at exposed offshore sites and to facilitate the gradual, cost effective exploitation of the huge offshore wind energy resource available in European Union waters. As part of this project, a measurement system has been installed on one of the wind-turbines to enable design and certification methods to be verified.
Research into ‘The Dynamic Response of Wind Turbine Structures in Waves’ is underway by Prof. J M R Graham (Imperial College) et al, funded by the UK DTI Renewable and New Energy Programme, Engineering and Physical Sciences Research Council – Renewable and New Energy Technologies; EPSRC - RNET, [5]
A report has been produced in Finland on the response of OWEC’s to pack ice [6]
‘BLADED for Windows’ and ‘TURBLOAD’ have been and are under development by Garrad Hassan. Validation and further development of existing aeroelastic models will be performed based on measurements at Blyth Harbour.
In t he Netherlands , ECN have developed two wind-turbine models,
· the time-domain PHATAS-IV [14]
· the frequency -domain TURBU with the TURBU -OFFSHORE extension currently in preparation [13]
In Germany, wind turbine manufacturers , certifying bodies and universities are also cooperating in the development of their individual design tools [12]
In Belgium an integrated dynamic model of the complete system is currently under development using Finite Element (FE) analysis.
Proprietary computational fluid dynamics programs, for example by CFX, a division of AEA Technology, are used for the analysis of flow around and the behaviour of turbine blades.
Other Danish ongoing research focus ses on:
· Aero-elasticity with special focus on offshore wind turbines.
· Design specifications for offshore wind farms
This section briefly describes research projects that have focused on the entire windfarm.
Cost O ptimising of L arge S cale O ffsh o re W ind F arms
This European funded project was undertaken jointly by S K power (lead Contractor), National W ind Power, Risø , Nellemann, Nielsen & Rauschenberger, Rostock Stadwerk and the Polytechical University of Madrid , under the Fourth Framework Programme, reference J OR 3950089 and was completed at the end of 1998.
T his project investigated the technical and economic feasibility of a large scale offshore wind farm in the range of 200 to 500 MW in the Danish waters of the Baltic Sea and a Langeland Belt by examine the meteorological conditions and North
Efficient Development of Offshore Windfarms [ENDOW]
This European-funded project is being undertaken jointly by Risø (lead contractor), Garrad Hassan, Ecofys, Uppsala University, Robert Gordon University, NEG-Micon, SEAS, Oldenburg University, ECN and Elsamproject. under the Fifth Framework Programme , Reference ERK6-1999-00001, and is due to be completed in July 2003.
Using experience gained through the demonstration projects currently operating offshore, the major objectives are to evaluate wake models in offshore environments and to develop and enhance existing wake and boundary-layer models to produce a design tool to assist planners and developers in optimising offshore wind farms.
Measurement O n and M odelling of O ffshore W ind F arms
This European funded project was undertaken jointly by Risø , B onus, Finnish Meteorological Institute and Madrid University under Third Framework Programme, reference JOU20350 and was completed in 1996. The main objectives of the project were to measure the nature of wind-turbine wakes at the Vindeby offshore wind farm , to investigate the structure of single and multiple wakes and to ch a racterise the relationship between turbulence and wind-shear with wind-turbine separation.
Fyndfarm , a tool for optimisation of wind farm configurations, has been developed in the Netherlands.
Availability M odel for O ffshore W ind F arms.
This project is funded by the Danish Energy Agency (DEA) under the UVE Programme, reference ENS-51171-98.0033.
The project is managed by Riso, Department of System Analysis in co-operation with SEAS and is expected to be completed at the end of 2001. The aim of th e project is the development of a general model for decision analysis for the optimisation of the availability of wind turbine farms offshore especially with respect to maintenance policy.. A determination of the balance between reliability of the turbines, their interconnections and tower access conditions will be carried out. The model will be constructed as an influence diagram, and relevant variables including those mentioned above will be taken into account. The variables will describe the farms geographical site, the turbines, including their main component reliabilities, the site climatic conditions, transport infrastructure, electrical connections, local as well as remote surveillance and control.
S tructural and Economic Optimisation of Bottom-Mounted Offshore Wind Energy Converters [Opti-OWECS]
This European funded project was undertaken jointly by TUDelft (lead contractor), University of Sunderland, Kvaerner O il and G as and Kvaerner Turbin u nder the Fo u rth Framework Programme, r eference JOR 3950087 and was completed at the end of 1997.
The overall objective of the st u dy was to identify designs leading to a reduction of the cost per generated kilowatt hour of offshore wind energy by using an i ntegrated approach in the design process.
Site Specific Design of Wind Turbines Based on Numerical Cost-Optimization.
This D anish project involves the direct use of site characteristics in the design process, when optimising wind turbines. Design loads are determined by use of detailed wind climate information for mountainous complex terrain, large offshore wind farms and very low or high annual wind speed. Benefits will be determined from the design of site-specific wind turbines and multi-site wind turbine s. Design guidelines will be established for the adaption of existing designs to a specific site with only small adjustments and for the design of entirely new wind turbines. Numerical optimisation will be used to optimise wind turbines for the specific site characteristics. Existing design tools will be improved by development a complete direct design method that combines state-of-the-art aero elastic calculations, wind modelling, cost modelling and numerical optimisation. Two three-bladed wind turbines based on different concepts will be modelled and the design load cases will be found for six wind climates. The benefits from site-specific design and the possibility for multi-site design will be evaluated covering both re-design of existing wind turbines and design of new wind turbines
In Denmark, a tool for LCA ( life cycle assessment ) of wind t urbines is being developed , which will enable the e nvironmental impact of wind turbines to be predicted.
Umweltforschungsplan des BMU (UFOPLAN): „Weiterer Ausbau der Windenergie im Hinblick auf den Klimaschutz“
This investigation was undertaken by BMU [Ministry of Environment Protection] and focused on the further development of wind energy use in Germany with respect to climate protection. It is an ongoing project and examin es :
· Further Development of Wind Energy Use on Land and Offshore
· Wind energy pricing (EEG Renewable energy Law)
· Repowering onshore
· Workshops on Offshore Wind energy Use in (April/June 2000)
· Integration of conflicting environmental interest
· Grid integration
· Feasibility of remote offshore wind energy
· Operational aspects of offshore wind energy use and cost of offshore wind
UFOPLAN: „Untersuchungen zur Vermeidung und Verminderung von Belastungen der Meeresumwelt durch Offshore-Windparks im küstenfernen Bereich der Nord- und Ostsee“
This investigation was undertaken by UBA [Federal Office for Environmental Protection] and focused on the state of the art for avoidance and minimisation of environmental impact by offshore wind farms on marine environment. It is an ongoing project and examin es :
· description of the state of the art with respect to environmental impacts on benthos, fish, birds, sea mammals
· development of IEA methodology
· risk analysis for ship collision
· formulation of measures to minimise impacts
· identification of knowledge deficits
Erfassung der Verbreitung, Häufigkeit und Wanderungen von See- und Wasservögeln in der deutschen Nordsee und Entwicklung eines Konzeptes zur Umsetzung internationaler Naturschutzziele (BOFFWATT)
This investigation was undertaken by BFN [Federal Office for Nature Preservation] and was completed in 1999; the report is available from BfN and covers:
· Investigation on sea bird populations in the German North Sea with respect to number of individuals and annual variations, feeding habits,
· development of a protection concept
· further need for research
See- und Wasservögel in der deutschen Ostsee und ihr Schutz im Rahmen internationaler Vereinbarungen
Additional ongoing study, also undertaken by BfN for the German Baltic Sea.
Erfassung und Bewertung ökologisch wertvoller Lebensräume in der Nordsee
Identification, investigation and determination of potential areas for marine nature preservation (with respect to FFH-protected areas) in the German North Sea. An ongoing project also undertaken by BfN.
Erfassung und Bewertung ökologisch wertvoller Lebensräume in der Ostsee
Identification, investigation and determination of potential areas for marine nature preservation (with respect to Baltic Sea Protected Areas (BSPAs)) in the German Baltic Sea. Completed in 1999 and a report is available from the authors, BfN.