Integrated ground modelling for offshore windfarm development; informing risk and foundation design

Combining data from geophysics, geotech, geology and GIS enables a more detailed picture of ground conditions before structural and geotechnical engineering design occur. The important feature of this model is that it is fully digital and ensures models and data is available to all those engaged with the project at any stage.

Overview

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(upbeat intense music)

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Hello, and welcome to the Seequent Lyceum

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2021 EMEA session.

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It is an absolute pleasure to bring you this event

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from wherever you may be joining us.

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As we know from the past 24 months, this could be anywhere.

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It could be from the office, the kitchen table,

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the kids playroom, or even sitting outside

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trying to get some vitamin D

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from being stuck inside your house for so long.

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It has been a tough period of time for everyone.

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So we hope you’re safe and well out there.

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My name is Jeremy O’Brien and I’m the segment director

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for energy here at Seequent.

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I also have my talented colleagues,

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Miguel and Fiamma here with me today.

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They based in the EMEA region,

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and will be helping us walk through the story

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of ground modeling for wind farms

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as part of the session today.

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Apart from the lockdowns affecting our personal lives

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and causing turmoil

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in our everyday routines including business,

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the world of energy has also been changing

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during this period too.

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Driven by an ambition of net zero emissions by 2050,

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the energy transition has gained momentum.

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Hydrogen, geothermal, wind, solar, biomass,

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carbon capture and storage.

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They are all energy sources receiving

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significant amounts of funding

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not only to get projects across the line,

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but also to perform the fundamental research required

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to make sure that energy applications

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are ready to fill the gaps,

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and the transition to a low carbon world.

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In this session today,

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we’re going to focus on offshore wind.

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Offshore wind is believed to be one of the only renewables

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capable of replacing fossil equivalent generation

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at a scale which can turn the needle

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as part of the transition.

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Offshore wind isn’t a new technology,

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however, it is never scaled at the rate

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it’s beginning to scale at today.

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Multiple challenges arrive

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around the scale of development on the seabed itself.

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And this fast pace of movement towards

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offshore floating facilities means

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that we’re dealing with engineering problems

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that we probably haven’t dealt with in this scale before.

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So where do we find ourselves?

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We find ourselves at this collision point

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of geotechnical engineering, or engineering geology,

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for those of that mind.

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Geophysics and structural engineering.

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But what we’re also seeing is different people

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from different industry verticals coming in.

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Oil and gas style geophysical analysis

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is likely to come to the fore,

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but vast quantities of seismic data

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are able to be reprocessed

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because these areas have traditionally been

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explored for hydrocarbons.

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Properties models available from this type of data analysis

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perhaps haven’t been applied as common practice

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in its main before, and could change the way

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we understand the near surface.

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New state of the art understanding

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of soil and rock properties,

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and high resolution understanding of the sea floor,

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allows us to not only understand that geomorphology,

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but to take such things as cables and unexploded ordnance,

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to ensure that these projects are undertaken

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in a safe and efficient manner.

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Now, if we can share our slide.

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Boiled down, the point of this is to reduce the risk

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around placing the foundations

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for these high CapEx costs projects,

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including putting turbines in the seabed.

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If we put these in sub optimal locations,

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this can do things like blow up project costs,

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which you don’t want, but also increase the time

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to market for this crucial type of energy

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through the transition.

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An integrated ground model, the subsurface,

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including geo-technical, geo-physical,

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geospatial, and geological data can help us facilitate this.

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And key things like reviewing that decision-making process

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around what type of data has been used in different areas.

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Having a digital version of this.

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So we’re not working from 2D cross sections

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and paper based analysis,

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really enables the whole project

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to be understood from one place.

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It also enables us to plan additional data acquisition

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or timing different parts of construction in a project

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to make sure there’s no overlap

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or misunderstanding between these two areas.

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And crucially, we actually, one of the big impacts

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of an integrated ground model is the ability

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for two of the foundations related to the wind turbines

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to be put in the ground in the most ideal places possible.

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And that’s really important when we start

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to think about the ground conditions

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that relate to wind modeling.

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So what are we looking for?

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We’re looking for clarity.

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And so, as I mentioned before, we have clarity

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when all the different disciplines

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around in the ground conditions have a home,

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and a way to be able to understand and review each other.

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Whether that’s our CAD designs and our engineering drawings,

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our geophysical data, our geological data

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that comes from CPT data or in bore hole testing,

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GIS data that tells us where existing pipelines

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or existing cables or unexploded ordnance might be.

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But then also the people who are in direct with the projects

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like consultants.

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We need all of these people to be able

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to find the information they need from the ground model.

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This integrated model really needs to ensure

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that data from these different disciplines

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can be understood by all stakeholders as I’ve mentioned.

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And also importantly, given we’ve got other

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industry verticals coming into this world,

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we need to ensure those domain standards

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or lack of connection between domains

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is removed as we move forward,

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to ensure the projects come online seamlessly.

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The big outcome from this is that this type of modeling

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will provide greater certainty in the ground conditions

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when undertaking the structural

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and geotechnical engineering required

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to make sure the turbines are securely in place.

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To highlight the power of the integrated approach,

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we actually use a case study based off real data

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from the Netherlands.

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One of the great things about this project

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is the fact that the offshore ground condition data,

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is freely available from the Dutch government.

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So it’s enabled us to work on this type of data,

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and build up models to show you the power

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of this integrated ground modeling approach.

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We’d like to thank the Dutch government

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for the openness and being able to share this data.

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Now, my colleague Fiamma, will take things from here,

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and introduce the ground modeling process.

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Over to you, Fiamma.

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<v ->Thanks, Jeremy.</v>

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Hello, I’m Fiamma.

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I’m the EMEA technical specialist

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for civil and environmental.

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So the location of this project

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is the Hollandse Kust Zuid.

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This site is 18 kilometers off the coast

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in the area between the Hague and Zandvoort.

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This area was auctioned between 2018 and 2019

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for a total of four wind farms.

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For 350 megawatts each, and a total of 1.4 gigawatts.

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The Dutch government performed all the site investigations

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to the risks, the tendering process,

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and made the data publicly available.

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So now I’m going to show you a video.

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So the idea with this project

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was that the different experts needed to work in parallel.

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The project structure mirrors perfectly this way of work

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with the master branch, where the integrated ground model

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puts together the products

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from the three discipline-specific branches

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that I will illustrate in a few minutes.

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So as you can see, we could generate

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a complex but seamless workflow

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in this flexible integrated ecosystem.

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And we were able to keep constant communication

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by leaving comments to each other,

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and tagging each other into 3D scenes

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as you’re going to see in a second.

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The goal for each project is really to create

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a strong integrated ground model

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generated by the seamless interaction

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among the relevant disciplines.

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So first, we need to ascertain which areas will be avoided

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when placing the turbines because of pre-existing hazards.

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So that’s when the geophysical data comes in our help

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with contacts from Mac, site scan sonar,

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plus preexisting GIS data from public domain,

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and seismic interpretation.

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So collating all of this information,

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we can generate a hazards map that indicates

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where boulders, shipwrecks, UXOs,

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and pre-existing cables and pipelines are located.

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Plus, polygons highlighting the potential

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for polyauton notes.

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Moving on to the seabed surface,

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this is when using a single file generated

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by the multi beam survey that represents

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the bathymetry of the area,

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we can evaluate the seabed mobility.

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To be ultimately fed into the seabed

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morpho dynamics analysis.

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So the little cones that you can see here

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represent lineation measurements

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that indicate during the migration direction.

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So the key of this flexible integrated environment,

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is that it allows us to incorporate all sorts of data.

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And one of the key components is seismic.

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So what you can see here is that we’ve brought in

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pre-existing interpretation performed on spots to the data,

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and you can also see the result of that interpretation.

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These model can further be validated

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using geology borehole data from borings.

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So this was the seismic analysis branch,

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but we’re going to be looking now

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at the geo technical analysis one.

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So meanwhile, the expert can generate soil volumes

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from categorized CPT data.

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Utilizing these numerical information from the raw data

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to build a geological model.

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Another layer of understanding can be added

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in digital technical analysis,

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and it’s provided by a numeric model

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generated from CPT row numeric parameters.

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What you’re also seeing here is that as new data

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is uploaded into the cloud,

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that results in a process of dynamic updating

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that cascades down to each product

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that has been generated from that data

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resulting in an updated interpretation.

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So as a next and last step in this phase of the work

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in geo statistical analysis branch,

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we utilize this tool to generate a block model,

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describing the probability to have a certain soil type

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into each block.

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And we can then provide further validation

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to our CPT driven geological model.

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So what you can see here is that we are comparing

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that soil volume from the more deterministic

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geological volume with the probability to have that soil

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in each block.

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So the brightest the color, the higher the probability.

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And finally, the result of this workflow

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is the generation of the integrated ground model

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that will provide indications

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for the foundation design process.

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So back to you, Jeremy.

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<v ->Thank you so much, Fiamma.</v>

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As you can see from that,

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we can build a fully integrated picture

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of the ground conditions,

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which could be likely to be encountered

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when looking at putting wind turbines in the seabed.

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One really important thing to think about here

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is this approach of combining

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the different disciplines of geoscience,

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and then enabling them all to come together.

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I’m really impressed by the way that we can use

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geo statistical workflows at this point

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to enable properties and understanding in a numeric way

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that can be downstream utilized in the engineering

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of the design of the foundation to the turbines.

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Now I’d like to hand things over to Miguel.

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What Miguel’s going to talk to us about,

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is why these ground models are so important

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when we actually go to the practical step

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of wanting to engineer how will these turbines

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are going to sit in the ground

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and be safely there to generate power,

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keeping our lights on at home.

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Miguel, over to you.

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<v ->Thank you, Jeremy.</v>

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So I’m Miguel Lahoz.

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I’m a product manager with the PLAXIS product line

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at Bentley systems.

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And what’s important to remember is that

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we don’t do ground models for the sake of the ground model.

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The end, the product of our work

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is going to be an offshore wind farm

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that safely and reliably produces electricity.

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So it’s the job of the foundation designer,

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and if we could pull up the slides please,

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to ensure that the structure and the surrounding ground

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will work together to resist the massive actions

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that are imposed on these ever-growing turbines.

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And also have to make sure that we can install

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and commission these in a very harsh environment.

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And in an ideal world, everything would work linearly.

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We would know in advance where these foundations will go.

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And then we would drill there, get wholesale information,

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all the data that we need for our design,

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and just proceed from there.

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But the reality is very different,

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and the layout of these type of offshore wind farms

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depend on many, many parameters that are interrelated.

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So that then it needs to be a very iterative process

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with even hundreds of iterations.

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Because as we were mentioning before,

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many factors condition the locations of these.

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We need to avoid geo hazards.

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We need to consider the block and wake effects

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that these turbines produce on the wind

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that insides on them.

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And we also need to optimize the costs,

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the global cost of our wind farms, not only the foundations,

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but also the cables that interlink them.

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So then we have…

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I see there’s some factors that determine the location.

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The location will determine the design of the foundation,

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and the design of the foundation will determine its cost.

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So then it feeds back again into the process.

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So we need to go into these loop several times.

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And for that, we also need to take into account

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these evolving, these dynamic modeling,

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and these evolving of the information

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that we have available.

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So at the beginning, we will have our conceptual designs

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with very simple models that require very little information

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with which we can iterate quickly.

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And as the project advances

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and we get more and more information,

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and we are able to predict

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more aspects of the soil structure behavior,

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we will advance into more detailed models

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that require more parameters

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and more information from the ground

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for the analysis.

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Another aspect to consider is the seabed mobility

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that we were discussing before.

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Not only, we’re not exactly sure

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of what our soil parameters will be,

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we’ll have them evolving in time.

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The position of the seabed can change

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during the lifetime of the structure

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by plus minus say, five meters.

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And this needs to be considered in our design,

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even added into more local effects,

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like the scour that the foundations themselves produce.

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So to take into account all of those,

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we have our geo-technical models,

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and there are many considering

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very different aspects of the soil behavior.

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But what is important about those,

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is that all our design tools are deterministic.

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So in the end, we need to consider

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a more or less homogeneous soil unit

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that has specific numerical parameters.

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And of course, we can vary these parameters,

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but every variation that we do is one initial analysis.

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So it has its cost.

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So we need to move from a percentage likelihood

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to something that actually models

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the behavior of the soil that has a numerical value

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that will produce certain conclusions

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that we can verify or validate.

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And same happens with the soil structure interaction.

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Our ground and our structure don’t work in isolation.

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They actually contribute in combination

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to the strength of the system,

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and our design tools need to model those.

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They need to model the slipping and the gapping

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that will occur between the foundation

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and the surrounding ground.

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Same as with the material models.

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The properties of these soil structure interaction

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are dependent on our location, on the type of soil,

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and on the numerical parameters that we’re assuming

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for each of our soil units.

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So as the project advances, they will evolve

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and they will get more and more detailed.

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And for many years, we have been tackling this the old way,

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I would say, by passing pieces of paper around or PDFs,

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which are essentially digital representations

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of a piece of paper.

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But a central integrated ground model

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that is updated dynamically

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goes a long way in getting us all on the same page,

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and helping us get more reliable and faster designs

[00:18:14.030]
for offshore wind farm.

[00:18:16.220]
So thank you, Jeremy, and back to you.

[00:18:21.390]
<v ->Thank you, Miguel.</v>

[00:18:22.223]
There’s really interesting insights

[00:18:24.270]
into the downstream impacts of the uncertainty

[00:18:27.540]
around understanding ground conditions,

[00:18:29.450]
and whether or not you have that information at hand

[00:18:31.380]
to be able to get an optimal design

[00:18:33.484]
for the foundation for your wind turbine.

[00:18:36.910]
So I hope that what you’ve seen in the past few minutes,

[00:18:38.810]
as you’ve seen a quite comprehensive overview

[00:18:42.670]
of an approach to an integrated ground model,

[00:18:45.580]
which enables not only the geological parameters offshore

[00:18:49.360]
to be understood, but the inclusion of anthropogenic items

[00:18:54.300]
such as cables, and UXOs,

[00:18:58.480]
and other items on the sea floor to be understood.

[00:19:01.060]
And all those things that then be included

[00:19:02.700]
with detail and analysis of the soil structure,

[00:19:05.660]
predictive geo statistical models of where

[00:19:08.460]
a particular soil type might be,

[00:19:10.560]
and utilizing seismic data, which may have been collected

[00:19:14.090]
years ago and reprocessing that

[00:19:15.810]
to enable further detailed analysis.

[00:19:18.293]
They’re all newly collected data for that matter.

[00:19:21.610]
So what we are seeing is this real collision

[00:19:24.190]
of different geosciences,

[00:19:26.150]
which have come from different industries

[00:19:27.790]
coming into this world, which is really exciting.

[00:19:30.690]
You then see the importance of that information

[00:19:33.100]
flowing then onto the actual design for the foundations

[00:19:36.527]
for the assets themselves.

[00:19:38.760]
Once the assets themselves are built,

[00:19:40.610]
we do not want to be coming back

[00:19:42.070]
and look at these again later.

[00:19:43.730]
So I think what you’ve started to see

[00:19:45.240]
is the interaction between the subsurface,

[00:19:48.072]
and then the construction and design

[00:19:51.010]
of the actual structures,

[00:19:51.980]
which are generating the electricity is really important.

[00:19:54.700]
Because at the end of the day,

[00:19:55.660]
what we’re offsetting here is a base load power generation,

[00:19:58.630]
which has been around for decades.

[00:20:00.060]
And we need to make sure the reliability

[00:20:01.937]
and the engineering associated with the new power sources

[00:20:06.180]
as we go through the energy transition,

[00:20:08.550]
is kept at a level which is high enough

[00:20:10.220]
to make sure that these things are reliable

[00:20:11.761]
in delivering us the power that can keep our lights on

[00:20:14.720]
and homes warm at the end of our day.

[00:20:18.310]
So with that, I really like to thank you for dialing in

[00:20:21.090]
and listening to the session on the integrated ground model.

[00:20:24.590]
And we really look forward to working with organizations

[00:20:27.832]
and helping them de-risk the underground

[00:20:30.352]
relating to these offshore wind projects around the world.

[00:20:34.140]
Thanks again for your time,

[00:20:35.490]
and we look forward to speaking with you all soon.

[00:20:38.562]
(upbeat intense music)