One of the more fascinating aspects of wind-energy production is how the sector is constantly searching for ways to co-exist with the nature that surrounds it. Yes, power creation is paramount, but studying and boosting the environment around it is a noble — and some would say — necessary goal.
To that end, understanding how floating offshore turbines interact with marine life becomes even more important. Through DemoSATH Lab, Saitec Offshore Technologies is using its operating floating wind demonstrator as a real-scale testing ground to study environmental interactions, improve monitoring methods, and explore solutions that support co-existence with marine biodiversity.
“The main goal is to test our technology at full size before we use it in commercial projects,” said Natalia Vélez, an environmental consultant at Saitec Offshore Technologies. “DemoSATH gives us the real data that we wanted from the sea and also from real operating experience. Computer models and tank tests are very important, but they cannot show us everything.
That’s why, with DemoSATH, we can improve the platform and the way we install and operate it. Also, we can reduce risks and costs, and this helps us to prepare our SATH technology for larger turbines in the future.”
Developing DemoSATH
Saitec Offshore Technologies designed and developed DemoSATH, a 2 MW floating wind turbine using SATH technology and it’s the engineering lead for the project, according to Vélez. Saitec Offshore has led the design, construction, and installation of the platform.
“We also work in its operation, maintenance, and improvement,” she said. “We do all of this together with our partners, RWE Renewables and The Kansai Electric Power Co. Inc. There are also other organizations that are working together with us in order to study this platform to have better results.”
The recent offshore operation marks a new step in DemoSATH Lab’s biodiversity program and forms part of the AQUASATH Project, with the installation of several complementary systems designed to study how floating wind foundations can host and support marine life while exploring their potential integration with aquaculture activities.
Environmental research has been a crucial component for Vélez and the team at Saitec from the beginning.
“We not only want to know if the platform works well; we also want to know if it interacts well with the sea,” she said. “Along these multiple surveys that we have done so far, we have seen many marine organisms already have settled in the platform and the structure, and they are using it and the area around it. That means the platform can offer — by itself — a suitable habitat, and that’s really interesting for us.”
Maintaining marine biodiversity
Early observations from DemoSATH Lab are helping the team understand what conditions may allow marine biodiversity and floating wind to coexist, according to Vélez.
“That’s why we want to test nature-inclusive designs, elements, and small aquaculture projects,” she said. “With this, we want to understand the full system: Which species can live there? How should we attach the systems? How do they adapt to local conditions? And how can we do the proper inspections and maintenance of the systems we are using? In that way, the DemoSATH Lab is helping us answer these questions before bigger floating projects begin.”
The DemoSATH turbine was installed over a sedimentary seabed with few natural sheltering areas. New structures in such environments tend to attract different species of marine life, according to Vélez.
“The floor is sedimentary; it’s only sand and a few rocks, and there’s not many sheltering areas for species,” she said. “Usually species, when they see something floating, it becomes very attractive to them because it’s like a small ecosystem.”
Nature-inclusive designs
Part of what makes the underwater structure so inviting to marine life is because DemoSATH has integrated nature-inclusive designs or NIDs on its infrastructure, according to Vélez.
“They are elements that can be integrated into an anthropogenic structure with the aim of enhancing the ecological functioning and creating additional opportunities for marine life,” she said. “These elements can create more surfaces, small spaces, or shelters for organisms. On the DemoSATH, we have already designed special NIDs for the columns below the water.”
In some of these areas, Saitec has created special cages filled with mussels and other bivalve animals, according to Vélez.
“The installation has already been done, and it is already showing us how to prepare, handle, and install for bigger projects,” she said.
The marine life species being transplanted are species from the area, according to Vélez, which will only aid in the further growth of the indigenous animals.
“We wanted to use living species from the area rather than from other locations,” she said. “One of the aspects we want to study is whether structures like this could eventually contribute to larval dispersal of local species.”
Biomimetic reefs
Part of the project also includes the creation of biomimetic reefs to aid in marine life adaptation, according to Vélez.
“A biomimetic reef is an artificial structure that is designed to reproduce some of the physical characteristics and ecological functions of natural reef habitats,” she said. “On the DemoSATH, we already installed life-boosting units or LBUs, designed and constructed by Ocean Ecostructures, a company from Barcelona. We installed some units in the braces below the water of the DemoSATH. Ocean Ecostructures used special material based on calcium carbonate and other minerals with three-dimensional shapes that create different spaces for marine life. It allows food and sheltering for young fishes.”
The ultimate goal is to learn if the floating turbine foundation can support marine life without affecting the safety and maintenance of the platform, according to Vélez.
“We don’t have final results yet, but we have seen that the offshore wind industry is showing more interest in biodiversity and nature-inclusive design specifically,” she said. “Companies want practical solutions and clear data, of course, and we are seeing that maybe the DemoSATH Lab is useful because we can test these ideas in a real operating platform and not only in a laboratory, for example. This is very important.”
Saitec and its foray into offshore wind
Saitec was founded in 1988 and has grown into one of Spain’s leading independent engineering firms with about 350 employees. The company works in different engineering areas such as transport, energy, water, architecture and urban planning, environment, and structures. This experience led to the company’s growth within the floating wind sector. In 2013, Saitec started developing its own floating wind technology called SATH, which in 2016 was presented through Saitec Offshore Technologies, a specialized spinoff of Saitec, according to Vélez.
In 2023, the DemoSATH project was installed at the Biscay Marine Energy Platform (BiMEP) off the coast of Armintza, Spain, with collaborations with RWE Renewables and the Kansai Electric Power.
The DemoSATH Lab became operational in 2024.
“At first, we studied marine life around the structure doing bird monitoring, using underwater cameras and ROV inspections, and analyzing the underwater noise,” Vélez said. “Later, we expanded our studies to bat monitoring, AI-based monitoring tools, biodiversity studies with the environmental DNA, nature-inclusive designs, and aquaculture.”
The progression of the project was, for lack of a better word, organic, according to Vélez.
“We first developed SATH technology with DemoSATH, and when we had it at full scale, then we started using it with our project,” she said. “We turned it into a laboratory for the next generation of floating offshore wind.”
Commercial possibilities
Even though the research being conducted at DemoSATH Lab is still in the experimental stage, Vélez said she has hopes for the results to bring positive momentum to the offshore wind sector.
“In many cases, the solutions we are testing have never been implemented before under real offshore conditions,” she said. “That means that what we are doing is extremely valuable.”
As with other offshore wind potential, the technology is only a small part of the ultimate commercial goal. Support from local communities, fishers, public authorities, and more will need to be considered as well, according to Vélez.
“If we show that offshore wind can support biodiversity on one side, and then work together with other sea activities, then the result will be more trustworthy and stronger,” she said. “In this way, we can help offshore wind develop faster and in a more responsible way.”
Being a marine ecologist, Vélez has particular interest in the DemoSATH Lab project and its potential to advance offshore wind.
“I’m really, really passionate with these topics, but in here, I’ve been more involved in the whole picture — not only in the water, but also outside it,” she said. “I am working with the monitoring around the whole platform.
That means not just studying the underwater biodiversity such as the fish, invertebrates and algae community, but also the presence of bats and birds, for example. This has been a good opportunity to be involved in the whole industry of offshore wind platforms and to understand the main goals that we need to achieve in order to progress in this industry.”
Collaborative efforts
The DemoSATH operation was coordinated by Saitec Offshore Technologies, which managed the protocol, installation checklists, documentation control, and overall follow-up of the works.
The live material was supplied by Mar Ceibe, while Instituto Kardala provided the raft used for the temporary suspension of the elements and technical support during the first day of operations. Kotazero carried out the underwater works, including the collection of the elements from the raft and their final installation on DemoSATH.
Amarradores de Santander provided the main vessel and operational support during the second stage, including the mooring works required on the platform. Grupo Peñascal Kooperatiba contributed to the creation of the NID elements.
Additionally, some of this work was funded by the Department of Industry, Energy Transition and Sustainability of the Basque Government, and the European Regional Development Fund (ERDF), under the Hazitek program through the AQUASATH Project.
Through DemoSATH Lab, Saitec Offshore Technologies is exploring how floating offshore wind can move beyond energy generation and contribute to a better understanding of coexistence with the marine environment.
More info saitec-offshore.com/en
