Site Characterization in Offshore Wind

TGS Podcast (00:00.)

Welcome to PowerPod, where TGS explores new energy solutions from renewables to innovation and the topic shaping the future of our industry.

Alexander Smith (00:18)

Hello from TGS, the world's leading energy data company. My name is Alexander Smith, Geophysical Advisor at TGS, and I'm hosting this TGS PowerPod episode on site characterization in offshore wind. We've recorded this in two parts, and this is part one.

Today, I'm joined by our head of site characterization, Tone Holm-Trudeng, and two guests from the offshore wind industry: Helen Sinclair, Site Investigation Package Manager, working on a variety of offshore wind farms, and Enda O’Doherty from the NISA Project.

Welcome all. Would you introduce yourselves, please?

Tone Holm-Trudeng (00:56)

I am Tone Holm Trudeng, head of site characterization in TGS. In site characterization, we are focusing on subsurface and seafloor imaging for offshore wind farm sites. Also focusing on CCS. We have had that department in TGS for the last five years. We come from oil and gas industry, but in the recent years, we also decided to focus our knowledge on developing our solutions for wind farm developers and CCS.

Helen Sinclair (01:25)

My name is Helen Sinclair. I'm an SI package manager. My background is geology, geophysics and geotechnical engineering. I've been working in the offshore energy sector for about 20 years now, but predominantly in the offshore wind sector for nine years. Started out in the fixed bottom world, surveying and then moved into the floating offshore world where I've been for the last five years.

Enda O’Doherty (01:52)

Hi everyone, my name is Endo O’Doherty. I'm the Site Investigation Manager for the NISA project. NISA is an acronym, N-I-S-A, which is the North Irish Sea Array project, which is off the east coast of Ireland. NISA is one of the Phase 1 offshore projects in Ireland, given special designated status from the Irish government as a means to hit our 2030 renewables targets. Yeah. I've worked in NISA now for nearly four years.

My background would be civil engineering, started in onshore renewables in Ireland, but I've worked in offshore wind for the best part of 10, 12 years now in different capacities, mainly consultancy work. I head up the geotechnical and geophysical works on the NISA project.

Alexander Smith (02:42)

Fantastic. Thank you all so much for joining. Today we're going to talk about two subjects I'm passionate about offshore wind and geoscience, specifically the role site characterization plays in enabling the development and construction of offshore wind. And to set the scene, perhaps it's helpful to explain how offshore winds have evolved over time.

Enda O’Doherty (03:00)

Yeah, well, the fact of the matter is that the wind turbine industry has evolved and turbines have increased in size over the decades. If we go back, you know, 30 years ago, we had kilovolt size machines that sort of evolved to what I would call workhorse machines around the two to three megawatts kind of platform. They're the best part of sort of the early 2000s going into the second decade this millennia that was sort of the real workhorse size of turbines that were used on and offshore.

Things have continued to increase and it looks like we still haven't hit the ceiling in terms of the size of turbines. Even in my time working on the NISA project that has continued to evolve. We're actively considering anything between 15 and north of 21 megawatts in terms of turbine size now. And that will probably continue to evolve as well.

That means bigger turbines, they can produce more power, they're physically bigger, and that in turn means larger foundations and just larger infrastructure in general to support them. As offshore wind has evolved as well, we always push the boundaries in terms of technology, but also I suppose the sites themselves, in terms of water depths, the complexity of ground conditions.

That all just adds to the challenge and the remit that the likes of myself and Helen and other SI package managers have to contend with. In terms of foundation concepts or solutions, like monopiles are the predominant foundation type for fixed bottom. I'm not sure of the exact statistics, but we're looking at around 80 % of fixed-bottom foundations are monopile types and that trend will continue for the simple fact that they are the most inexpensive, they're the simplest by design and we have evolved even in terms of our design ability to optimize their viability for sites as well. We currently have a ceiling of around 60 metre water depth for fixed-bottom. I'm confident that will be broken and exceeded.

We will continue to push the bounds of that for fixed bottom as well. What the end point is, we can't say yet and there's a lot of advancements even in the transport installation aspect of offshore wind farms as well. We will get bigger vessels, bigger drills, bigger lifting equipment and that will then again push the boundary of the sites that are available for fixed bottom foundations. So, yeah, we're always striving for innovation, but that doesn't make the job maybe any easier for from our side, but it does make it super interesting all the time. Yeah.

Alexander Smith (06:00)

Helen, given Enda’s description there of the evolution of offshore winds, chasing ever greater wind speeds, bigger turbines, deeper water, and inevitably encountering a variety of geological settings. Can you describe the purpose of site characterization in defining geological risks and obstacles and what needs to be assessed before construction begins?

Helen Sinclair (06:22)

Sure. So, we go through several phases of characterizing a site. Initial phase will involve geophysical surveying followed by usually a MET-ocean campaign with lidars and wave boys, et cetera, to understand the conditions on site. The geophysical data will allow us to move on to the next phase, which is usually the geotechnical campaign where we go down and acquire soil samples from below the seabed. Combining the geophysical and the geotechnical data together, we use those to inform ourselves of the soil properties in terms of strength, as well as identifying geohazards such as mud volcanoes, which I've had on a few sites. All sorts of crazy things as well as human debris from shipwrecks and existing infrastructure. So, we put all of that together to help inform ourselves as to the conditions on the site to define the layout, how many turbines we can fit on the site, as well as defining our anchoring or foundation design.

And it also informs us in terms of our cable packages, so the types of cables, the sizes of cables, how deep they need to be buried. And all of this sort of comes together to provide us with a model essentially of the wind farm site. And as we go through the engineering and the design process of designing anchors or cables, we undertake more specific surveying in terms of additional geotech or maybe additional detailed geophys, for example, 3D geophys. And this all sort of comes together to build a story, to build an idea of the site in order to move forward into the manufacturing of everything and the construction and installation phase of the projects.

Alexander Smith (08:35)

Thanks Helen. Tone, we hear from Helen about building this this ground model. This 3D story of the site and the geology. Can you describe how and when these site characterization activities are performed?

Tone Holm-Trudeng (00:56)

Yes, Alex. So typically for site characterization, it occurs in several stages throughout the wind farm development. So, early development stages, typically a very sparse 2D acquisition from seismic is performed, what we call a wide reconnaissance survey, to understand initial conditions of the subsurface to get the initial thought and insight to what's down there. This is to do a site feasibility and also for consenting and starting to decide on in what shape and form the wind farm should be developed.

And then after that, typically after a year or two or even further, depending on the wind farm, it's followed by more detailed investigations to look further into the soil properties and then gain a better understanding of the subsurface and the foundation type one should select for that specific site. And then when it comes to getting that understanding of the subsurface from a geophysical point of view, there are different measurements one can undertake to understand that from the seabed to around approximately 100 meters subsurface for fixed bottom and a bit shallower for floating. But in general, we can say we need to look from seabed and now to around 100 meters subsurface. So, on the geophysical side, we acquire something called multi-beam echo sounder.

And with that, we get an image of the seafloor, the bathometry, and also then the water depth, which is a key information for the wind farm developers to understand. We also have seafloor imaging systems to get the seafloor features like boulders, wrecks that Helen mentioned, sediments, and how it looks on the seafloor to also plan the wind farm development. We do acquire magnetometer data, which is detection of objects like unexploded ordnance that we need to identify and remove before anything can be installed on the subsurface.

And then also sub-bottom profiler, which is really imaging the approximately 20 meters of the subsurface from seafloor down to approximately 20 meters below seafloor. And then all the geotechnical testing is done by in situ testing on the seafloor and into the subsurface. To date, the conventional methods and geophysical methods for wind farm development have been something we call 2D ultra-high resolution. With 2D, we mean that it's seismic lines acquired with some sort of distance between the lines. So we acquire a grid of lines and we get a subsurface image on the exact line, but the image in between the lines are not there. We don't see the information between the 2D lines. This is where the 3D comes in. By acquiring what we in the seismic world call 3D data, we acquire a cube of data. We now start to see between the lines as well. We see the full picture of the subsurface.

This is very key and important when there are geological complexities as Helen referred to. Then the advantage of having the full picture is absolutely there.

Alexander Smith (08:35)

Thanks, Tone. Helen, Tone touches on the geotechnical sampling and with your background and expertise, could you expand on the key drivers for gathering geotechnical data and maybe just briefly describe the different sampling techniques.

Helen Sinclair (12:51)

So, the geotechnical survey involves two different processes. First one is undertaking what's called CPT, which is a cone penetration test. That's where we push a calibrated cone essentially into the seabed and we measure the resistance of which that has as it goes down to the seabed. And we characterize the soils based upon its various soil properties that we can extract through various empirical methods from that data.

We can do that through two methods. One is just pushing straight from the seabed and the other method is we drill, push the cone down through the hole and we keep moving down to get to deeper and deeper depths. The reason we have the two separate methods is because we can't push all the way to necessarily the depth that we need data from just from the seabed because the system won't allow it. So, we have to sometimes go deeper, particularly when we're dealing with offshore substation foundation design, which can be, you know, 70 metre depth, 80 metre depth of information we're needing below the seabed.

The second form of geotechnical data we acquire is sampling. It's similar to oil and gas drilling an oil well, we do the same thing but with a much smaller diameter hole. It's only a couple inches, a few inches wide. And so, we basically drill down through the sediments, acquiring samples as we go. We do this in both soil and in rock. Sometimes we need to, we have shallow rock on site, so sometimes we need to understand the properties of the rock that we may need to anchor into if that is necessary.

From there we undertake a number of tests on those soil samples or rock samples that we acquire and those inform us in terms of the soil strengths, its elastic properties, density, the types of sediment it is, whether it's clay, whether it's sand, or if you're unfortunate enough to have carbonate limestone soils that can be quite challenging in certain parts of the world. And these provide the inputs into the engineering phase for designing of the foundations and designing of cables. Particularly in cables, we need to understand the thermal properties of the soils so that we can ensure that the cables don't overheat and fail as a result of that.

Alexander Smith (15:33)

Thanks Helen. So, just to summarize, we've got the geophysical data, which covers the seabed, and then we have this grid of data, seismic data, and then we have these geotechnical locations, which are this sort of vertical penetration into the seabed. Could you just say something about the difference in resolution? Do you see different things in the data?

Helen Sinclair (15:58)

Yes. So obviously, geophysics can cover a much wider area, whereas geotechnical is essentially a data point in the site. I mean, it's as if, if you imagine looking around your room, if you put a hole in one part of your office, you might hit a desk, you might hit a chair, or you might just hit the floor. We're trying to identify all those different surfaces within the subsurface to give us an engineering profile that we will design to for in terms of fixed bottom for the foundations, in of floating for the anchors and our mooring designs.

Alexander Smith (16:45)

Enda, I want to turn to you at this point because I know NISA has acquired this geophysical data that Tone has described site coverage and the UHR3D and then you've also got the geotechnical data too. Can you explain to us the benefits to the project in terms of defining the soil conditions, enabling a design of foundations and wind farm layouts, you know, how does it all come together?

Enda O’Doherty (17:09)

Yeah. We touched on a brief there by mentioning all the concept of the ground model. The ground model is key in terms of, know, ground condition characterization. In fact, I would see my main objective or my main role as site investigation manager is to get a ground model that is both robust enough that a certification body can effectively approve it, but also, excuse the pun, the foundation on which other design teams will rely on for their design activities, the most notable being foundation design.

So that ground model, in essence, is a structural geological model. And in the case of the NISA project and all the projects in Ireland, actually quite a good starting point in terms of openly available data from the Infomar program. And different countries and different territories will have different levels of data, the sort of pre-existing open-source data on geology, be it geotech or geophysics. Unfortunately for Ireland, we haven't had sort of heavy industry offshore, that we haven't had a sort of pre-existing oil and gas industry.

We haven't had large infrastructure offshore. So we don't have the same level of sort of insight you could say compared to a lot of countries. But I think that gap has been almost filled in by the Infomar program. The Infomar program was led up by the GSI, Geological Society of Ireland and the Marine Institute. And that gave us quite a good understanding of the main underlying geology on the NISA site, so that informed us on the prelim phase. We actually had the prelim ground model to start with and that was a really useful starting point.

A lot of projects may not have that geological model to rely on. And the intention always is to keep refining that, to evolve it to make it as robust as possible, to reduce the uncertainty. Ultimately, we are trying to reduce uncertainty as much as possible. When we got to the detailed phase of our site investigation work with NISA, the first phase is always geophysics, under any campaign, geophysics is always the precursor to geotech.

And the question that was put to me and the rest of the engineering team was, well, what does our geophysical survey look like and what is our SI strategy moving forward? One quirk of the Irish regime is that we can't define a turbine layout just yet. And the development sort of life cycle of Ireland means that the consenting regime means that we need to try and provide a fixed layout, but we can't really do that just yet. So we need to try and develop the ground model in such a way that it retains flexibility in the layout. And that just means building a robust as a ground model as possible.

And that really led us down the route of the kind of blanket coverage, one and done approach to our detailed geophysics. We would survey the entirety of the site and have that full understanding of the regional geology that sort of underlies NISA. And effectively that gives us the comfort that as and when we have final layouts, be it turbines, cabling, etc, etc, that can be effectively dropped down on top of the ground model and then you can extract soil unitizations, look at your soil stratigraphy and hopefully in time we will be able to get to the point we can infer or derive properties from our seismic data.

And I think that's going to be really interesting that up until now our approach in the geophysical sense has been fundamentally seismic stratigraphic units, know, firming up your subsoil horizons, know, picking reflectors and sort of defining those unit boundaries. But if we can take it one step further to infer properties of those units via the seismic data, I think that's hugely powerful. As we touch in there with Helen, the geotechnical sampling, often referred to ground truthing, that is correct in a sense, but I say this as someone who comes from a strong bias in geotechnical works.

I'm not a geophysicist and I'm not ashamed to admit it, but I think my difference here, if you like, from a sort of a geo perspective is that you have to admit maybe the limitations of geotechnical data as well. In that one decent, they're a very discrete sample and the more variable your site is and more challenging it is, and we're seeing more and more of these now, not that it devalues the geotechnical sampling, but if you can get properties or parameters from your seismic data, again, on that regional scale across your entire site, that's hugely advantageous, not just in terms of the ground model, but particularly in terms of no design activities when you look towards the real, what I would call proper design elements like feed design, moving into detail design. If you have regional scale parameterization, that is super, super useful. And we're very curious to see where that ends up going in the years to come for renewables, certainly.

Alexander Smith (22:45)

Absolutely. We're going to discuss that in a bit more detail, the methodology, and then the products that can come out of that Enda, thank you.

I'll summarize at this point where we've talked about offshore wind to date, which is predominantly comprising fixed bottom foundations like monopiles or jacket structures. These require site characterization to understand the soils present for designing the structures, the cables and then any hazards which affect the layouts and installation of the turbines. These site characterization activities include acquiring an array of geophysical sensors to get an accurate and resolute image of the seabed and the subsea soils, and then a complementary geotechnical campaign to provide very high accuracy, high resolution, one dimensional data and samples from the soils directly.

Thank you for listening to part one. Please join us for part two, straight after this. Remember to subscribe to the PowerPod podcast and join us again next time as we unpack more from the world of new energy solutions. Goodbye.

TGS Podcast (00:00.)

Welcome to PowerPod, where TGS explores new energy solutions from renewables to innovation and the topic shaping the future of our industry.

Alexander Smith (00:18)

Hello from TGS, the world's leading energy data company. My name is Alexander Smith, Geophysical Advisor at TGS, and this TGS PowerPod episode is on site characterization in offshore wind. We've recorded this in two parts, and this is part two. In the first part, we talked about the evolution of offshore wind and the vital role that site characterization plays in enabling the design and construction of them. In part two, we talk about the rise of floating wind, challenges in developing in deep water and possible solutions through innovations in site characterization.

As offshore wind continues to evolve into deeper water locations too deep for fixed bottom foundations, they increasingly require floating wind technology. Helen, in your experience with developing floating sites, what are the biggest hurdles facing this transition into deeper water and what role does site characterization play to ensure viable and safe development?

Helen Sinclair (01:25)

Yes, so as Enda has already alluded to in his projects, a lot of these floating projects are in parts of the world that haven't had heavy industry, haven't had oil and gas. For example, offshore Italy is one of the key places that is now moving into the floating section. And because of that, we have limited availability of public domain data. So site investigation becomes even more crucial earlier on in those kinds of projects, so that we can start designing and also dealing with the consenting and environmental impact assessments earlier.

Because we don't have that backlog of oil and gas data, for example, we need to characterize the site earlier and quicker, which presents its own challenge in the basis of…because we're moving into that deeper water section, you know, up to over 100 meters water depths, when we start to get to that sort of 300 to 500 and some of the projects I've worked on are over a thousand meter water depths. There's very few vessels that can undertake geotechnical surveying in those kinds of waters. Now, oil and gas, we have done that in Gulf of Mexico, offshore Brazil, Angola. But those kind of vessels are totally out of the reach of offshore wind projects on the basis of costs are just astronomical. And so, there are a few vessels that can undertake these deep water geotech projects that are accessible to offshore wind. But as we get beyond that sort of 700 meters is kind of really the kind of pushing, really pushing the boundaries.

We're starting to use new technologies such as seabed drills and things in order to try and reach those depths. On top of that, because you have the increased depths, we are working generally further offshore and so you're more vulnerable to weather conditions on site. We appreciate we're trying to build these in the windiest sites possible, otherwise we wouldn't be doing it.

But that in itself brings bigger challenges with the deeper water sites because we have bigger waves, everything is just bigger. And we require bigger weather windows in order to get that geotech data, to get the geophysics data, which can be extremely challenging in a lot of these sites. And so, we're all trying to fight for the same small pool of vessels in the same optimum weather conditions, which is always summer.

It's just presenting a bigger and bigger challenge to a lot of projects to try and get the days they need, then the timeline for the project it needs. And so yeah, they're a lot more challenging, but equally a lot more exciting.

Alexander Smith (04:25)

Is the data that's required different from that of a fixed bottom wind farm wave just got one contact point on the seabed? How does the anchor design affect site characterization?

Helen Sinclair (04:35)

In terms of the types of data, it's exactly the same. There's no difference really. We might do slightly different lab tests, but in terms of the data acquisition, the geophysics and Geotech, we acquire the same data. For floating projects in terms of the Geotech, the guidance is kind of evolving because it's such a new area. We haven't got that sort of back catalogue of projects that the industry has learned from.

A lot of the stuff, the guidelines that we use are from oil and gas type projects, which have because of the nature of oil and gas, because obviously if you have an accident, you're releasing hydrocarbons into the environment, they're quite restrictive in terms of the data acquisition requirements, which is not necessarily appropriate for offshore wind on the basis that we're not dealing with hydrocarbons, we're dealing with electricity.

And so it's a different kind of risk profile essentially if something were to fail. In terms of cables and things like that, it's exactly the same for oil and gas with flexible flow lines and pipelines, they have the same issues, the same challenges, with the exception of, obviously, as I mentioned previously, the overheating of cables can result in failure. But from a mooring and anchoring perspective, using technology like 3D geophysical surveys, allowing us to laterally and vertically translate soil properties across the site, we're hoping in sort of the offshore wind floating department, to be able to reduce the amount of geotech that we need to acquire, which will be significantly beneficial to projects budgets, but also in terms of our schedules.

Alexander Smith (06:38)

To put it into scale then, if you have a wind farm of a hundred monopiles, you would have to do effectively a hundred CPTs or geotechnical tests. But then if you have a hundred floating turbines with say five anchors each, you would need to test every one of those anchors, so suddenly it becomes 500 test points?

Helen Sinclair (07:02)

Well, this is the current question. So, we've now got the first project going through the certification process in terms of what will be required. And so, it's not quite set in stone yet because of the nature of floating projects and the types of anchors that we may use. If, for example, if we're using a drag embedment anchor, we don't necessarily know exactly where that is going to going to hold.

And so because of that, the requirement of doing geotech at every single location hasn't been defined yet, particularly with the addition of the 3D geophysics. So, I think it will be interesting to see how the first project goes, going through it at the moment to see where that lands. But it's not just from a certification standpoint, it's also from the supply chain.

They have to feel comfortable in terms of designing anchors that have had soil properties extracted from geophysics. To a lot of engineers, we know they see geophysics as the black box in the corner that scares them. So, it's going to be an interesting learning curve from all sides really to see how we can reduce our project risk as well as, you know, just taking everybody along with us on this wonderful 3D world.

Alexander Smith (08:25)

Tone, I turn to you to help explain what's in this black box. We've heard from Enda and Helen both about the power of 3D and the fact that engineering properties from soil can be derived. Can you describe to us the process to go from 3D seismic data into these engineering properties?

Tone Holm-Trudeng (08:46)

Yes, absolutely. And Alex, it's a very good point from both Enda and Helen and we know that right, that often, and especially in wind farms, this can be a very black box. And from my experience from oil and gas as well, we have encountered the same type of questions, right? From early phase days in oil and gas where we had the same skepticism against using seismic rock, inverted properties from seismic into geological modeling for oil and gas.

But on that side, we’ve come very far in terms of acceptance extracting the value you can get of extracting rock properties from seismic. And by that, saving a lot of cost on wells, drilling wells, because one can smart replace the wells in oil and gas by using seismic and seismic-driven rock properties. That's the same, then that over to offshore wind farms, where we're not talking about wells, but we're talking about the geotechnical testing, which is also time consuming and can be very costly. By using seismics to better place and decide where to do the geotechnical measurements can be a great benefit in terms of using the seismic.

And I will not go into, think, Alex, in this episode, at least, on very detailed geophysical deep dive into how we get from reflection seismic into rock properties. But what one does is when you send out a seismic wave that goes through the subsurface and comes back, that's what seismic is. If you take that seismic wave and you go backwards, same as inverting, that seismic inversion or constant of interpretation, you predict the subsurface that wave went through.

That's seismic inversion on a high level. So, the seismic is actually the rocks. You just need some tools to go from seismic back to the rock properties. But it's not really a black box because it is actually the rock properties that creates that seismic image. And we do have many different tools of going from seismic back to those rock properties.

And also think we need to work with the wind farm developers, the geotechnical engineers, the other parts of the technical community to really understand the value of this as well. And we have a way to go, but we have started and I'm sure the value will be seen as we go down that road.

Alexander Smith (11:20)

Thanks, Tone. It sounds so promising, but how close is it to being widely adopted by industry?

Tone Holm-Trudeng (11:25)

From my observation, talking to industry leaders, Windfarm developers, going to conferences and so on, it's a very hot topic these days in terms of quantum interpretation, going from seismic to rock properties. On all conferences and so on, it's at least three, four talks addressing this. We also have specific examples of wind farm developers who are doing this. That's public knowledge. One is the RVO (Rijksdienst voor Ondernemend Nederland). For RVO in the Netherlands, so for the RVO offshore wind farms, they are conducting seismic inversion for their ground modeling.

We are also working on the joint industry project led by the Det Norske Veritas, DNV, where we are working on using 3D seismic data together with the integrated geophysical measurements and go use that with quantum interpretation to get the ground model and by that have industry-wide recommended practice for using seismic derived soil properties in anchoring design. So, it's a large industry focus because we do know a knowledge that we need to do something to decrease the timeline and also the requirement for a number of geotechnical measurements we'll need to conduct on a wind farm site.

Alexander Smith (12:48)

Thank you, Tone. I'll take time now to summarize what we've covered in part two. We've talked about floating wind, we've talked about the challenges it brings to site characterization, both environmental, working in deep water and in rough weather conditions, but also from a technical point of having to potentially sample many different anchor locations in order to get appropriate level of certification, design and layouts, et cetera. Part of the solution could be using UHR3D seismic data. Tone described the process of seismic inversion to derive engineering properties, a process called quantitative interpretation.

So with this approach, a question to you all, as offshore wind continues to scale up, timelines shrink, costs remain a significant factor in the final investment decision -could UHR 3D surveys coupled with integrated sensors with complimentary geotech and innovations that come from it like quantitative interpretation for engineering properties, could this potentially be an answer to significantly reduced time and expense over a more traditional approach to sign investigation? Enda I'll start with you.

Enda O’Doherty (14:10)

Yeah, I think the key word there is probably integrated. And maybe something we haven't spoke about here, but in the case of the NISA project, the work we had done with TGS was a single-pass solution. It combined both the seismic spread and a geophysical spread, for lack of better word. And that has a huge upside in terms of time and cost. And whilst we want to have, you know, we're sort of engineers and technicians who want to have a robust of the data set as possible.

The commercial implications of these we need to be mindful of. There's no point, you know, it's futile presenting a hugely expensive campaign that's going to take far too long, too costly, but that just won't be attractive to projects and decision makers. So, these things do need to be sort of optimal from a time and cost perspective.

And I do think the 3D UHR approach, you know, combined with geophysical sensors is a very cost effective solution. It may not have been one time. I think it's been really interesting to see how TGS have almost scaled down from oil and gas to make it appropriate for renewables. I think to date the approach with 3D UHRS and renewables at least has been more local. Now we've looked at defined locations and it's almost been seen as a sort risk mitigation method prior to construction.

We have our known location, have done our geotechnical sampling, we have our ground model, but as one last exercise to kind of de-risk that location, we will sort of interrogate the ground conditions in more detail via seismic techniques. But if you use that level of resolution or interrogation of the ground conditions and expand it across your entire site, obviously you have more geological understanding.

And I think one of the key things that should play out is that you should be able to balance your geophysical seismic efforts against your geotechnical efforts. The fact of the matter is geotechnical sampling is expensive. And as we go deeper and deeper with depth of interest for renewables, particularly into rock as well, where rotary coring techniques in rock are by far and away the most expensive geotechnical sampling technique.

So if you can save know a nominal percentage of that geotechnical effort by that sort of regional scale geophysical effort you've done like that will definitely be a cost effective solution. There'll be no hard and sort of fast rules on this, each side is different each side will have their own strategy if you like, but I firmly believe that people in my position I would extol the virtues of 3D UHRS early.

It won't be an easy sell, we're still talking about a multi-million euro survey campaign, but the understanding and data you will get earlier in your project will pay dividends. The most obvious saving is in the geotechnical sampling. We spoke earlier about just using comparative examples of 100 monopiles with one GI location of each versus say a floating project with maybe four or five anchor points and a whole sort of plethora of CPT sound needs at each location.

Like I think that's maybe the wrong approach in some ways. It is useful for people to understand what efforts you need to go to to characterize each discrete location. But there's no playbook, essentially. We can have all the guidance documents and specifications. And I know DNV have the JIP at the moment in play, in terms of coming up with a specification, if you like, for floating winds.

But effectively, they're still guidance documents, engineering judgment will still play a large part in that. So, in the case of say, geotechnical sampling, rather than sort of peppering the seabed with multitudes of CBTs to get background truth in, I would argue that exploiting the full potential of your seismic data because that is done on shore, all things done on shore and the desktop environment will be cheaper than sending expensive survey vessels spending days and weeks taking geotechnical samples.

It's maybe arguably a difficult thing to sell. I would admit to myself, 18 months, two years ago, I was firmly in the skepticism camp, that kind of black box of this geophysical interpretation. I probably, if I'm being really truthful, I only really wanted the interpreter reports. I just wanted my solid unitizations. I have completely changed my tune on that. I think that you should endeavor to characterize your site as robustly as possible.

I do think the 3D UHRS is a major, major step forward. Yeah, I would encourage people to look at it more, and to look at it earlier on, if at all possible, because the benefits aren't just engineering, like we focus on that a lot, obviously, but there's huge upside for environmental assessments to alleviate your consenting journey and any jurisdiction as well. So, the more data you have early, the more you can do with it. And it's very interesting to see how we can kind of leverage that potential just depend on, I suppose, the end objective, be it design or environmental assessments. We'll see what industry ends up, but there's huge potential for, I think, offsetting your geotechnical effort.

Alexander Smith (19:45)

Thanks, Enda. And it brings me such joy to hear of a civil engineer converted to the power of site characterization.

Enda O`Doherty (20:13)

Converted would be a strong word, but at least more sympathetic.

Alexander Smith (20:20)

Helen, we've just heard there Enda's experience of using the UHR 3D data and the power it can bring to unlocking engineering potentials and problem solving. Can you bring from your experience of the many wind farms you've worked on, do you see that this approach of early site-wide integrated geophysics with geotech can significantly reduce time and expense? Is it always practical to do so?

Helen Sinclair (20:24)

Yes. I mean, I've worked on a lot of fixed bottom as well as floating projects. And one thing that any site and vestige and package manager dreads to hear is we've changed the layout again. I guarantee you during the, from the initial phases through to construction, the layout will change a dozen times. I had one project where it literally changed five times in a week.

So how do you plan a geotechnical campaign that allows maximum flexibility for positioning of wind turbines, of positioning into ray cables, offshore substations, positioning of those, they can move around the site so it can be extremely challenging because once you've done your initial geotechnical campaign, you're probably only going to do one more.

It's a site-specific, location-specific campaign, whether it's for testing areas on the site that have been highlighted as being uncertain, or whether it's to provide soil profiles for each of those foundations or anchors. It's a near impossibility thing to do, and so that's why I feel that 3D geophysics will really help us provide the engineering teams with the flexibility to change their designs, their layouts. And so, I do see it as being quite an important tool from as earlier phase as possible.

Now, the challenge that we have as SI package managers is sometimes getting the funding for these sorts of things. Because we're always at the front end of projects, we know that the project has got a lot more work to do. It's got a lot of expense coming after us, in terms of the design and then the actual construction. It can be quite challenging to get money for something that is not traditional that is not “the way that we've always done it” is the phrase that gets mentioned quite a lot.

So, I have worked on a number of projects that looked at 3D and I still believe they would have benefited from it, but it just didn't fit in with the cost profile of the project at that point. Particularly if you're working in regions that are either waiting for their first CFD auction like Italy or countries like Sweden and Finland who don't, they don't do CFD auctions. It's a project by project system.

So, it can be very difficult to try to get those money bags open to spend on something that some people would see as a luxury on a project. It’s seen because it's come from oil and gas as it gold plating the world of site investigation. You know, we are working with smaller profit margins than oil and gas. you know, we can't necessarily do the things that they do in oil and gas, but I think there are certain things that actually would be a huge cost saver as Enda mentioned that, you know, it's a huge cost saver going forward.

If we don't have to do two geotech campaigns, you know, that's massive. That's saving you millions upon millions of pounds on your survey. Not to mention giving you that project flexibility, reducing that overall site risk and of course helping the grand scheme of the overall project schedule, which is another thing that seems to flex and change as the project moves on, particularly if you're on a tight project that you can't necessarily afford to do two phases of geotech because this takes so long to do lab testing that you need to be able to pretty much get everything you need in one season. Pretty crazy to do, but yeah, I wouldn't advise it from a sanity perspective, if nothing else. But it's certainly something that I would definitely promote as an overall benefit to projects going forward.

Alexander Smith (20:20)

Thanks Helen. Thanks to you all for coming on today and sharing your invaluable insights. I'm sure everybody will find it as interesting as I do to listen to it. We've got time now just for the last words from each of you. So perhaps what are your hopes, maybe not your dreams for site-characterization in the near future. Tone, I'll start with you.

Tone Holm-Trudeng (25:25)

Thanks, Alex, thank you, and then Helen as well. I'm very excited for the industry in terms of what potential lies there. That we can use data to make data-driven decisions to reduce both the cost and also the timeline for wind farm development. It's really exciting to be part of this journey together with our partners and customers and really push and develop how we can use geophysical insights into reducing timeline and costs for our customers and partners. I think I want to end on that, Alex.

Alexander Smith (26:00)

Thanks, Tone. Enda?

Enda O`Doherty (26:02)

Yeah, I think that concept of integration is key for me, both integration of so-called traditional geophysical sensors with your seismic spread, then also integrating that with geotechnical work. To see more of an amalgamation of the two approaches, I think, would be hugely beneficial. And I've learned a lot personally on my own project on how to do that. And I think others should be sort of pushed or nudged in that direction.

And obviously I think the potential for derivation of engineering properties or parameters from seismic data, you know, QI, different version techniques, really curious to see what that ends up in the months and years to come. yeah, looking forward to that.

Alexander Smith (26:48)

Thanks Enda. And Helen...

Helen Sinclair

Yeah. So, from my perspective, I want to help the other packages be as flexible and as productive as they possibly can. So, from my perspective, getting as much data as I can to help them refine their engineering solutions and just generally overall support the projects in keeping costs as low as they can go. I mean, there's always that joke that as a geo, I never have enough data. I always want more data. And obviously the 3D geophysics is kind of the holy grail of all the data you could possibly have.

But I do feel that the more information that we can provide the engineers, the better that their understanding of the site is and the improvements that they can make to their designs of foundations or anchors save significant costs on projects. It also allows them to potentially select different suppliers and so that helps the overall supply chain in terms of not only manufacture, but also the constructing element.

If they have really enormous foundations, then you're limited on the number of vessels that can install these things, and the costs start spiraling on the project. So, anything that we can do from an SI perspective to really overall help the projects get to a point where the cost and the timelines are aligned then, you know, yeah, let's do it. Let's use all this innovative technology that we have been using for so long in oil and gas and even in the mining sector. Why not use it to really support our colleagues in the challenges that they have to build in some of these really challenging parts of the world.

Alexander Smith (26:48)

Great closing remarks. Thanks to you all. And Helen, you throw the gauntlet down there. Why not implement these technologies that are now available, we just got to find the right time and place for them.

Thank you all for listening. Remember to subscribe to the podcast and join us again next time as we unpack more from the world of new energy solutions. Goodbye.