A scientific team on marine sciences and geography of the University of Barcelona, the University of Girona (UdG), the Centre for Advanced Studies of Blanes (CEAB-CSIC) and the Institute of Marine Sciences (ICM-CSIC) recommends excluding and moving offshore wind farms from the protected areas in the Mediterranean due to the serious negative impacts these facilities can cause on the marine biodiversity and the landscape. This is one of the main conclusions of the team's paper, published in the journal Science of the Total Environment, which includes the participation of the lecturer Jordi Solé, from the Department of Earth and Ocean Dynamics of the Faculty of Earth Sciences of the UB.

The study presents a first evaluation of the potential environmental impacts of the wind farms in the Mediterranean, and especially in areas with a great ecological fragility and a high landscape value. As a study case, it analyzes the large-scale offshore wind farm in Cap de Creus and in the Gulf of Roses, where there are eight protected marine areas. The team reviewed nearly 150 papers from around the world. This diagnosis aims to be useful in other Mediterranean areas and other seas and oceans of the world that feature a high diversity, the existence of protected marine areas, a valuable landscape, and important fishing and tourist activities at a local scale.

In particular, the study fully analyzes for the first time the different impacts that these systems can have on the water column: from plankton to the marine seafloors; from fish and essential crustaceans for fishing to delicate and protected species, such as whales, dolphins, turtles and some seabirds.

The article highlights that the large-scale offshore wind farms can entail "serious environmental risks to the seafloors and the biodiversity of many areas in the Mediterranean due to the specific ecological, socioeconomic features and the vulnerability of this semi-enclosed sea." Therefore, "models such as those in the Northern seas cannot be imported directly," where there are many offshore wind farms. For the team, the Mediterranean is known for its "narrower but more heterogeneous shelf and a higher proportion of threatened species and habitats than Northern European seas."

Wind farms, complex structures

The structures of the wind turbines are complex. Under the water, the floating wind farms—those that would be set up in the Mediterranean—require huge mooring and anchorage systems that can affect the integrity of the seafloors. Marine mammals can collide or can get tangled up in the wires. Also, the noise caused by the wind farms accumulates with other sounds from human activities—such as sailing—and it has a negative impact on the behavior of marine mammals. Moreover, these floating platforms are also attracting for invasive species or opportunist species that can alter the fragile balance of the biodiversity. Researchers are especially worried about this phenomenon because the arrival of exotic species affects the Mediterranean more than any other European sea.

In addition, the floating wind turbines—which are more than 250 meters high—can alter the dynamics of the local atmospheric and oceanic currents. This situation can affect the production of plankton in a sea that is usually low in nutrients.

The study also defends the need for maintaining the marine biodiversity to fight against climate change and mitigate its effects. According to the authors of the article, marine habitats have a great carbon storage potential and are a solution to this problem, which is based on nature itself. For the scientists, the ecosystems with a higher biodiversity are the most resistant to the impacts of climate change.

Protected areas in Cap de Creus

The ecological impacts of the marine wind farms would be "especially harsh in areas with a high biodiversity and fragility such as Cap de Creus and the Gulf of Roses," warn the authors. There are eight converging protected areas at this point, which are nationally and internationally acknowledged. According to the international agreements, it is necessary to protect at least the 30% of the seas and oceans by 2030. The researchers note that at the moment, this figure in Spain currently represents 12%.

The paper warns about the risks of incidents associated with extreme meteorological phenomena, which will become more common due to climate change. It also warns about the inherent problems to the wind turbines, such as the structure failing into the sea and ship collisions. The scientific team emphasizes that these projects involve the industrialization of the coast in areas with a high landscape value. On the one hand, we should expand the capacity of the closest harbors to set the logistics related to the building and maintenance of the offshore wind farms. On the other, the harbors would house the infrastructures that produce energy from hydrogen, which can involve specific risks on the environment related to the uses of water and soil, the release of brine or hydrogen fruits, among others.

Last, the study states that the impacts will not be noticed in the coast only, but they will reach inland and coastal towns. These towns will have to house infrastructures (access roads, substations, transmission lines or temporary structures) that can damage fragile ecosystems such as wetlands, for example.

Fishing and tourism

The paper notes that the exclusion of the fishing activity—including artisanal fishing—of the affected areas by the offshore wind farms can have economic, social and environmental consequences for the fishermen, the fishing industry, the coastal communities that depend on this sector, and society in general. In addition, the sounds, vibration, and the electromagnetic fields of the cables can echo on captures.

The authors say that the debate on the potential impacts of the marine wind farms on the landscape will become more intense in the Mediterranean than in the Northern countries, and it has to do with the relevance of the coastal and maritime tourism of this sea. For instance, the wind farm projected in Cap de Creus would be built between eight and thirty kilometers from the coast, while in 2019, the average distance of all the marine wind farms in Europe was nearly 60 kilometers from the coast. Economically speaking, a study carried out in the Catalan coast calculated a loss of income of 203 million euros per tourist season.

More recommendations to protect the environment

The study ends with a series of recommendations for the policymakers in order to "rationalize the race of offshore wind farm proposals in the Mediterranean by the energy companies." According to the scientists, they should first apply the precautionary principle "to guarantee the highest level of protection for the environment through preventive decision-taking in cases of clear environmental risks, like the case of Costa Brava."

The paper also mentions the mandatory fulfillment of the EU mandates regarding the blue economy. The authors support an ecosystem approach, that is, not only considering the diversity of species and habitats but also the ecological functions in different areas—nursing areas, feeding areas, migration corridors, etc.—as well as the associated ecosystem goods and services.

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