It has probably escaped no one that we are in the middle of a climate crisis and a mass extinction. In the meanwhile, we know that the electricity demand in both Finland and Sweden will double by 2050. Our society is in dire need of more green energy, and wind power is a key factor in the energy transition. The areas marked for wind energy production in the marine spatial plan of Åland have been deemed suitable due to the small impact on people and the marine environment.
“We cannot and will not sacrifice the environment and biodiversity while mitigating the climate crisis and responding to society’s demand for electricity. These topics must be handled side by side”, says Stefan Husa, marine biologist and Head of Maritime Spatial Planning at Ilmatar Offshore.
Different types of foundations
In our waters, sunlight reaches approximately 20 meters under the sea surface and creates life habitats for flora and fauna. Algae and plants convert solar energy into a life force, bind carbon dioxide, and become food for all kinds of invertebrates, such as larvae, molluscs and crustacea. These, in turn, feed birds and fish which are then eaten by top predators, such as seals, raptors and humans. Deeper down on the seabed, on the other hand, it is quite peaceful. Only a handful of species, such as bristle worms, threadworms and small crustacea thrive in the bottom sediment of soft seabeds.Hard seabeds provide better conditions for life thanks to sessile species that create better habitats for other species. But far out in the sea at depths unreachable by sunlight, the conditions are not especially advantageous for any complex ecosystems.
In the areas north of Åland where offshore wind is currently being developed, the depth varies between 10 and 70 meters and the environment is characterized by both soft and hard seabed.
“This means that we have to investigate different types of foundations, both so-called monopiles, which are cylinders that are driven down, gravity-based foundations that stand on the seafloor and are kept in place by their weight, and jacket foundations that are anchored at the bottom by brace frames”, Stefan Husa explains.
When installed in a marine environment, a wind turbine foundation that reaches all the way from the seabed to the surface creates new vertical surfaces with sunlight. Foundations are protected with erosion control mattresses that protect the foundation against erosion caused by water flow. Both foundations and erosion control mattresses are permanent installations that with time have the potential to gain the function of artificial reefs.
Increased biodiversity in the long term
In a report from the Finnish Environment Institute, Syke, published in January 2022, researchers from six different Finnish organisations have mapped areas that are suitable for offshore wind. The report states that it is possible to develop large-scale wind parks in all Finnish sea areas in a cost effective manner without causing significant damage to inhabitants in coastal communities or their livelihoods and with minimal impact to the marine environment.
– We are naturally very aware that we will impact both the environment and its wildlife during the construction period. But in the long run, we can actually make a positive contribution to biodiversity, while the turbines produce large amounts of renewable energy, says Stefan Husa.
– In principle, all human activity leaves an imprint on the environment. Nothing is black and white. What we can do, however, is take informed and well-founded decisions. Through environmental permits and environmental impact assessments, it is ensured that the impacts on the marine environment are minimal and that we as constructors comply with all the applicable legislative requirements. This is also why our ongoing investigations of the seabed in the Sea of Åland are so important. They will determine both how many turbines can be installed in the area, what kind of foundations are suitable and where they should be built in order to minimize damage and maximize advantages.
