Marine Renewable Energy – ICE Conference Delegate Pack – DHI
CONFERENCE NEWSLETTERMarine Renewable Energy – Meeting the NeedUniversity of Plymouth, Monday 1 October 2012NEWS RESEARCHTeraWatt project – large scale interactive coupled 3D Radar @ Sea – prize winning poster at EWEA 2012 windmodelling for wave and tidal energy resource and energy conferenceenvironmental impact using MIKE by DHI software Wind power fluctuations strongly affect offshore wind farms. Weather radars offer a promising tool for the development of aScotland has substantial wave and tidal energy resources and is at the dedicated monitoring and short-term prediction system. Aforefront of the development of marine renewable technologies and collaborative research project between Vattenfall, DTU, DONG,ocean energy exploitation. Wave and tidal energy devices will soon be and ourselves was awarded a prize for originality and futuredeployed in arrays, with many sites being developed. It is therefore expectations at the EWEA 2012 event in Copenhagen. Theessential to understand how a number of multi-site developments research project suggests how the use of weather radar cancollectively impact on the physical and biological processes over a improve operations for offshore wind farms, giving earlywider region. Careful selection of array sites may enable the optimum warnings for shut-down during wind-burst conditions.exploitation of the resource while minimising any environmentalimpacts to an acceptable level. Please take a copy of the poster from our table.The TeraWatt project is a £1m project funded by the Engineering andPhysical Sciences Research Council through its Marine Challenge Fund.The project consortium has been established under the auspices of the CASE STORYMarine Alliance for Science and Technology for Scotland (MASTS) with Supporting tidal energy - metocean design conditions inscientists from the Universities of Heriot-Watt, Edinburgh, Highlands the Pentland Firthand Islands, Strathclyde, Swansea and Aberdeen, and Marine Scotland The Pentland Firth in Scotland is one of the most energeticScience (MSS). marine sites in Europe making it highly attractive for tidal energy projects. However, the site is also exposed to severe waveThe overarching objective of the research is to generate a suite of conditions, presenting a very challenging environment for suchmethodologies that can provide a better understanding of the impact of activities.energy extraction on the resource. Approaches will also be developedthat can be employed to assess the physical and ecological The MeyGen tidal stream project plans to build a 398MW turbineconsequences of changes to the resource. The project objective will be array – generating electricity equivalent to that required tomet by investigating spatial changes in wave climate, physical power 400,000 homes – in the Inner Sound of the Pentland Firth.processes affecting sediments, the shoreline & seabed, and the impacts In order to ensure optimal design of the foundations and turbineon organisms living in the seabed, their distribution and the superstructure, MeyGen commissioned us to provide designsignificance of these for other ecological processes. criteria, fatigue, and operational MetOcean data at the site. The study observed severe wave-current interaction in the area.MIKE by DHI software has been chosen by the TeraWatt Consortium to This occurs when tidal currents are sufficiently strong to alter thesupport their research. Coupled MIKE 3 FMHD and MIKE 21 SW characteristics of the wave climate. In conditions where tidalmodels form the foundations of the adopted MIKE software platform. currents oppose the waves, extremely steep waves are produced.These core models will be augmented by MIKE 21 BW, MIKE 3 FMMT, We were able to simulate this process and capture waves ofMIKE 3 FMST, LITPACK, MIKE 3 FM ECO Lab & ABM Lab, EVA and similar steepness to those observed. Our results will be used byMIKE Animator in order to consider the specific responsibilities of each MeyGen to further optimise their turbine design and ensure thatpartner university. their structures are able to withstand the harshest conditions expected in their design lives. Moreover, turbine installation can be planned to maximise safety and minimise cost and downtime. Deployment of the first units is planned to commence in 2014. “...In a recent review by the UK Crown Estate, it was found that of all the bidders that have won rights to install tidal and wave arrays around the UK, more than 90% used the MIKE by DHI software.”
SOFTWARE SUMMARYMarine Renewable Energy – Meeting the NeedUniversity of Plymouth, Monday 1 October 2012MIKE 21 / 3 FM HDHydrodynamic modelling in two– and three–dimensionsThe Hydrodynamic Module included in MIKE 21 & MIKE 3 Flow Model FM simulates water level variations and unsteady flows in response to avariety of forcing functions in the marine environment including density variations, bathymetry and external forcings. It also provides thebasis for computations performed in many other modules. The choice between 2D and 3D model depends on a number of factors. Forexample, in shallow waters, wind and tidal current are often sufficient to keep the water column well-mixed, i.e. homogeneous in salinity andtemperature. In such cases a 2D model can be used. In water bodies with stratification, either by density or by species (ecology), a 3D modelshould be used. The modelling system is based on the numerical solution of the two-/three-dimensional incompressible Reynolds averaged Navier-Stokes equations subject to the assumptions of Boussinesq and of hydrostatic pressure. The model, therefore, consists of continuity, momentum, temperature, salinity and density equations and it is closed by a turbulent closure scheme. The density does not depend on the pressure, but only on the temperature and the salinity. For the 3D model, the free surface is taken into account using a sigma-coordinate transformation approach. The spatial discretisation of the primitive equations is performed using a cell-centred finite volume method. The spatial domain is discretised by subdivision of the continuum into non-overlapping elements/cells. In the horizontal plane an unstructured mesh is used while a structured mesh is used in the vertical domain of the 3D model. In the 2D model the elements can be triangles or quadrilateral elements. In the 3D model the elements can be prisms or bricks whose horizontal faces are triangles and quadrilateral elements, respectively.MIKE 21 SWSimulating offshore and nearshore wave fieldsMIKE 21 SW is a 3rd generation spectral wind-wave model that simulates the growth, decay and transformation of wind-generated waves andswell in offshore and coastal areas. It is used for a wide range of wave climates assessments in offshore and coastal areas, both hindcast andforecast mode, including design of offshore, coastal and port structures, where accurate assessment of wave loads is of utmost importance tothe safe and economic design of these structures.MIKE 21 SW solves the spectral wave action balance equation formulated ineither Cartesian or spherical coordinates. At each mesh point, the wave fieldis represented by a discrete two-dimensional wave action density spectrumusing either a fully spectral or directional decoupled parametric formulation.The discretisation of the governing equations in geographical and spectralspace is performed using cell-centred finite volume method. In geographicaldomain an unstructured mesh is used. The time integration is performedusing a fractional step approach where a multi-sequence explicit method isapplied for the propagation of wave action.The model includes the following physical phenomena; wave growth byaction of wind, non-linear wave-wave interaction, dissipation by white-capping, dissipation by wave breaking, dissipation due to bottom friction,refraction due to depth variations, and wave-current interaction.MIKE 21 SW is also used for the calculation of the sediment transport, which for a large part is determined by wave conditions and associatedwave-induced currents. The wave-induced current is generated by the gradients in radiation stresses that occur in the surf zone. MIKE 21 SWcan be used to calculate the wave conditions and associated radiation stresses. The long-shore currents and sediment transport is thencalculated using the flow and sediment transport models available in the MIKE 21 package.
WATER RESOURCES GROUNDWATER & POROUS MEDIAReshaping the scene of water resources FEFLOWRelease 2012 provides a range of significant new FEFLOW 6.1 sets a new standard in groundwaterdevelopments and features for the water resources modelling by providing the entire range of itssoftware products. functionality in one modern user interface. In addition to introducing a new GUI, FEFLOW 6.1Selected examples are: has several new features: MIKE HYDRO BASIN Display of calibration targets and statistics The future GUI platform for DHI’s water resources Selective mesh smoothing products, MIKE HYDRO, is introduced. Release 2012 Stereoscopic views and image/video export includes the River Basin Water Management module (WM) used for IWRM, water resources assessment, Improved multiscreen support water allocation, reservoir operation and other Text display in view windows types of analysis, planning and management model Improved isoline display and labelling studies Improved path line visualisation Expression based user variables MIKE FLOOD AD Improved map data handling Advection-dispersion modelling is now available Selection from 3D maps in MIKE FLOOD. With this release, fully dynamic, coupled HD and AD simulations can be made - both The range of the FEFLOW 6.0 Classic user interface for the Cartesian and Flexible Mesh versions functionality made accessible via the Standard interface includes: MIKE 11 Engine upgrade The simulation engine of MIKE 11 has been Editing of time dependent material properties upgraded to a 64-bit application. Hence, the Budget groups simulation speed has been increased and any Expression based selection and assignment memory constraints during simulations have been Convenient editor for unsaturated properties removed Editing of discrete feature elements Tool for spatially distributed rainfall generation Borehole heat exchanger A new tool for preprocessing of station-based Manual mesh editing temporal data is now available for the creation of Expression based material properties 2D spatial and temporal varying grid files using Chemical reaction definition either the Thiessen polygons or the inverse distance Fluid flux analyser weighting methodology MIKE SHE parallelised AD solver MIKE by DHI Facilitating tomorrows MIKE SHE’s AD solvers have been optimised for parallel processing resulting in increased model Release 2012 needs performance. This development is an extension of the parallelisation of HD solvers released in 2011 Head office: Agern Allé 5 DK-2970 Hørsholm Denmark Tel: +45 4516 9333 firstname.lastname@example.org www.dhigroup.com
MIKE by DHI CITIES COAST & SEAWater modelling software - and much more MIKE URBAN - the complete urban water package Defining new frontiers in the marine areaDHI is the leading global provider of knowledge of water MIKE URBAN version 2012 continues to offer its users high Version 2012 of the marine products is full of newenvironments, and the MIKE product family is the main productivity and harvest the benefits from improved performance facilities designed to enhance the applications ofvehicle for making our global expertise accessible. The as well as new features like calibration plots and reports. The these products even further.MIKE products are continually being improved with the latter feature supports plots of measured and simulated data andlatest research and development carried out at one of can either show comparisons between time series or statisticalDHI’s research centres - very often in collaboration with data.leading universities or other partners. Furthermore, a new set of tools for improved usability (eg whenAccessibility is a keyword for DHIs know-how. We strive building a 1D/1D storm water model) is available for both theconstantly to provide easy and affordable access to our MOUSE and SWMM components:global knowledge. Apart from the MIKE products with Catchment slope and length calculationstheir embedded know-how and expertise, DHI also offers Cross section extraction from DEMa wide range of training courses in many languages and in Lateral snapping of nodes A few selected examples:more than 30 countries worldwide. Auto connection of overland network to storm water Linux porting of simulation engines network The MIKE 21 and MIKE 3 simulation engines in theYou can find updated training schedules here: Sequential labelling of nodes FM series are ported for execution on Linux computers, www.mikebydhi.com/Training.aspx thus allowing simulations on massive computer clustersReliability is another keyword. You can safely rely on top Catchment delineation based on digital elevation models MIKE Animator Plusquality software and efficient, local support and training improves the accuracy compared to pure geometrical methods. A new version of the popular MIKE Animator withfrom DHI. Your investment in MIKE software and in enhanced and improved functionalities (includingwater modelling competence is safeguarded by the fact support for MIKE 3 files)that DHI is the global leader in knowledge and modellingtechnology for water environments. Agent based modelling A brand new module, called ABM Lab, is being launched with Release 2012. ABM Lab is used for modelling theThe MIKE by DHI Release 2012 continues the proud behaviour and fate of moving agents, typically fish ortradition of frontier developments and increased value other living organisms, in the water environment. ABMfor our users. We are confident that you will agree! Lab integrates seamlessly with ECO Lab or may be used on its own Improved structures Important improvements in the MIKE 21 and MIKE 3 structure descriptions, including improved descriptions of tidal turbines Enhanced 2D overland flow features 2D initial conditions as a constant value - from polygons or from external polygon layers 2D water level and inflow boundaries Spatially distributed rainfall onto a 2D grid Modelling engine enhancements of MIKE URBAN CS An additional 1D engine, MIKE 1D, designed and optimised for parallel processing 64-bit support for the MOUSE engine
DHI CASE STORYHelping Atlantis tune to the tidesProviding comprehensive analyses of tidal energy resource sites Tidal flows vary greatly with geography, across the globe. Also, interaction SUMMARY between turbines within a prime spot can impact the intensity and direction of tidal flows themselves – locally and regionally. As such, the success of Client sustainable, financial risk-reduced and cost-effective tidal power generation Atlantis Resources Corporation depends on the accurate knowledge of tidal energy flow at specific sites. In (Atlantis) short, it is imperative to identify the best site within an area of interest, to Challenge make successful tidal power generation a reality. With our global experience, Large variance in tidal flows state-of-the-art software and dedicated Decision Support System (DSS), we worldwide helped our client – Atlantis Resources Corporation – to do just that. Inefficient utilisation of tidal energy resources Tidal turbines – heralding the future of renewable energy Lack of knowledge on tidal site Tidal turbines take up approximately 1/1000 of the space of a wind turbine characterisation for the same yield due to the greater density of water. Also, the resource is Financial risks and uncertainties 90% predictable. However, in order to ensure optimisation of the resource, for companies and investors it is necessary to identify an area with sufficient flow, combined with the Solution appropriate depths, at a suitable distance from land and free from shipping Detailed site investigations and lines and other environmental impacts. analyses Accurate site modelling and a As such, the tidal energy sector is still in the pioneering phase. In compari- dedicated Decision Support son with conventional hydropower and wind energy, tidal power is a diffi- System (DSS) cult resource to tap into and many uncertainties still surround successful Comprehensive planning and tidal power generation. However, it is becoming increasingly likely to suc- forecasting of yield to the power ceed and at DHI, we have an important role to play in its future success. Curi- grid osity and a common sense approach are pre-requisites for development of Recommendations for optimal tidal power generation sites any kind. These coupled with science and accuracy (numerical models) are set to make tidal power the ‘next big thing’ in the renewable energy sector. Value Enabling the client to select optimal sites for tidal power generation Aiding in the development of tidal power generation sites Significant financial risk reduction for the company and investor Marked contribution to the green/renewable energy sector Tidal energy knowledge made globally accessible through our MIKE software Atlantis 1MW AR1000 turbine prior to installation for open ocean testing at the European Marine Energy Centre (EMEC)
DHI CASE STORYPredicting scour in offshore wind turbines – now a breezeMaking offshore wind energy more viable with long-term scour prediction tools The total offshore wind power capacity is expected to touch 75GW by 2020 and SUMMARY the possibilities are immense. However, the offshore wind energy industry is still stricken with the burden of heavy capital investments. Our newly Client developed tool – ‘WiTuS’ can lighten that load. With WiTuS, we can predict This is a research project funded by long-term mono pile scouring – this can help in simplifying turbine designs, the Danish Council for Strategic effectively reducing the investment required. Research (DFS)/Energy and Environment Offshore wind farms demand a heavy price Challenge Offshore wind power refers to electricity generated from wind in wind farms Protect wind turbine constructed in water bodies. Offshore wind farms are expensive – invest- foundations against scour ment prices can touch €3million/MW. The installation of the offshore wind Heavy investment (up to turbine is a complex procedure. It generally comprises one third to half of €150,000/turbine) in scour protection due to lack of long- the total investment in the wind farm, while the rest is comprised of infra- term predictability structure, maintenance and oversight. Also larger turbines with more energy capture capability, make more economic sense, when starting an offshore Solution wind project. Thus, the larger the turbines, the greater the investment costs. Our tool ‘WiTuS’ enables prediction of scour around mono piles over The mono pile – rooted in movement long time spans Although deep water floating wind turbines are being developed, most off- shore wind farms today still utilise traditional fixed-bottom foundation tech- nologies. Different types of foundations are used depending on the depth of Value water at which the turbine is being installed. These include monopile, gravi- Long-term scour predictions can ty based, tripod, suction bucket and conventional steel jacket structures. Of slash scour protection invest- these, monopile foundations have been the preferred foundation type so far. ments by as much as €150,000/ This is owing to the fact that they have an edge over other foundation types turbine –this is approximately 6- in shallow water, mainly with regards to construction, production, assembly 10% of the total average project and cost efficiency. cost This tool is customized to fore- A monopile foundation utilises a single pile structure driven 10-40m into the cast scour around monopiles. However, it can be applied to seabed depending on the any offshore and coastal pile- expected loads on the structure where long-term scour wind turbine. When the development is an issue monopile is installed, it If the environmental conditions rises 10-15m above the are predicted, scour develop- mean sea level. The wind ment around the structure can turbine is later placed be better forecasted above it. As such, the monopile has to support all the loads on and from the wind turbine as well as loads from waves on the foundation. Example of a predicted scour hole, using WiTuS
Weather radars – A new pair of eyes for offshore wind farms? PO. ID Pierre-Julien Trombe1 Pierre Pinson1 Claire Vincent2 Henrik Madsen1 Niels E. Jensen3 Thomas Bøvith4 Nina F. Le5 Anders Sommer6 75 (1) Technical University of Denmark, DTU Informatics, Denmark (2) Technical University of Denmark, DTU Wind Energy, Denmark (3) Danish Hydraulic Institute (DHI), Denmark (4) Danish Meteorological Institute (DMI), Denmark (5) DONG Energy, Denmark (6) Vattenfall Danmark A/S, Denmark Background Experimental Setup The substantial impact of wind power fluctuations at A Local Area Weather Radar (LAWR, X-band, from DHI) large offshore wind farms calls for the development of was installed at Horns Rev in the frame of the Danish dedicated monitoring and short-term (0-6 hours) project Radar@Sea prediction approaches Additional Radar images are available from a Doppler Recent observations at the offshore site of Horns Rev radar (C-band) at Rømø on the west coast of Denmark revealed the presence of convective rain cells as a meteorological indicator for extreme wind variability and suggested the use of weather radars for detecting and tracking such phenomena (Vincent et al. 2011) Typical situation of Open Cellular Convection over the North Sea west of Denmark Objectives and MethodologyResults / Example Episodes Our objectives are To monitor weather conditions in the vicinity of the offshore wind farm (for environmental studies, security of onsite personnel, etc.) To characterize the local weather phenomena that lead to enhanced power fluctuations To embed that knowledge in forecasting methodologies so as to obtain improvedTypical fall and predictionswinter situations To account for this regime-switching behavior in the wind farm controller with large weather fronts Time-series of wind and power observations are modeled so as to highlight their mean and trailing behavior and variability, as well as regime-switching aspects, with precipitation Unobserved regime sequences (MSAR-GARCH statistical models – Trombe et al. (2012)) cells affectingwind and power Observed regime sequences (based on explanatory variables eg. wind direction or based on fluctuations the information given by radar images) Methods from image analysis are used to extract and track features in images from both radarsTypical summer situation withsummer storms hitting the offshore wind farm References / Further Reading Conclusions Pinson P, Madsen H (2012) Adaptive modeling and forecasting of wind power fluctuations with Markov- switching autoregressive models. Journal of Forecasting, available online Pinson P (2012) Very short-term probabilistic forecasting of wind power with generalized logit-Normal Weather radars may become crucial onsite remote-sensing distributions. Journal of the Royal Statistical Society, Series C, available online instruments for future large offshore wind farms Trombe P-J, Pinson P, Madsen H (2012) A general probabilistic forecasting framework for offshore wind power fluctuations. Energies 5: 621-657 Significant collaborative R&D with meteorologists, radar Vincent CL, Hahmann AN, Kelly MC (2011) Idealized mesoscale model simulations of open cellular convection experts, forecasters and wind farms operators is required over the Sea. Boundary-Layer Meteorology 142: 103-121 to fully exploit the new information provided by such Vincent CL, Pinson P, Giebel G (2011) Wind fluctuations over the North Sea. International Journal of remote-sensing instruments Climatology 31: 1584-1595 Acknowledgements: This work is supported by the Danish Public Service Obligation (PSO) fund project Radar@Sea (under contract PSO2009-1-0226) which is gratefully acknowledged. We are grateful to the Danish Meteorological Institute (DMI) for sharing the data from the Rømø radar. We also thank Vattenfall and DONG Energy respectively, for providing wind power data from the Horns Rev 1 wind farm and the images generated by the LAWR. Thanks also to http://www.eumetrain.org/ for the satellite image. EWEA 2012, Copenhagen, Denmark: Europe’s Premier Wind Energy Event