Offshore wind power

The impacts of offshore wind farms on the water system, soil and bedrock ensue from construction work carried out on the seabed, including the building of the power plant’s foundations and the installation of power transmission cables. Construction work may result in the dispersion of sedimented nutrients and harmful substances, including heavy metals, dioxin or furan. On the other hand, the concentrations of these substances in offshore areas are generally low and the impact would be transient, and the impact would thus be of minor significance as a whole. Regarding the potential identified in offshore areas, it should be noted that the infrastructure required for wind power operations, such as transport routes and cabling, would load the areas through which they pass, even if the actual production took place offshore.

Construction work on sites with significant species and habitats, such as reefs, will cause local impacts on these habitats and species (spawning grounds, fish migration routes). The spawning times of fish should thus be taken into account when planning the construction of foundations. The greatest part of valuable underwater habitats are located in shallower areas and closer to the shore, however, rather than in potential areas designated for offshore wind power production[2]. On the other hand, the foundations may also function as artificial reefs once the environment in the vicinity of the construction site has recovered. It should be noted that in the planning process, a model was relied on which takes into account the sensitivity of the marine environment as well as protected areas and values. The identified potential sites for offshore wind power production are found in areas where the stress on marine environment caused by them can be minimised.

Power plants may also have harmful effects on birds and bats. Impacts caused by direct animal collisions have proved to be relatively minor, however, and based on experience gained from wind turbines on land, it would appear that birds are able to circumnavigate any wind farms on their migratory routes or fly between wind turbines.[3] The fact that birds tend to avoid wind farms may also result in habitat loss. 

From the climate perspective, offshore wind power enables electricity generation with low greenhouse gas emissions.[4]  The construction of offshore wind farms will increase the proportion of low-emission energy in the grid and replace fossil energy, resulting in positive climate impacts.

The plan designates a total surface area of approx. 3,500 km2 to offshore wind power production. The average space requirement for an offshore wind power plant is 5 MW/km2, which means that the designated areas will enable an output of approx. 15.7 GW (the vision defined by WindEurope for Finland is 15 GW by 2050).[5] Should these projects go ahead, significant business opportunities for the Finnish energy sector would be created. The construction of offshore wind farms as well as their operation and maintenance would create significant employment, both directly and indirectly. The construction of offshore wind farms represents a greater workload than land-based farms, and their impacts on employment would thus also be more significant. The construction of offshore wind farms would also have an indirect impact on the accommodation sector, as especially in the initial stages and before Finnish competence can be built up, the builders may come from overseas.[6]

For the maritime industry and shipping operators, the construction and operation of offshore wind farms would offer new business opportunities. Finnish companies have expertise in offshore construction and coping with ice conditions. Investments in offshore wind power would support the development of this cluster of expertise, potentially creating significant export opportunities. Foundation solutions, the construction phase as well as operation and maintenance require specialist equipment, which few of the operators in the sector currently use. Ports will presumably be used for the intermediate storage of turbine components and as bases for maintenance and crew vessels.

The areas designated for offshore wind power have large surface areas, and they are located far from main grid access points. From the perspective of exploiting the identified potential, the level of the investment costs will be essential. Among other things, this factor will be influenced by the trend in energy prices and more precise definition of the planning areas (seabed quality, water depth, and distance from the coast).

Offshore wind farms’ impacts on traffic and logistics will be minor once the plants are operational; they will be located far from other human activities and only require minor maintenance traffic. The Maritime Spatial Plan plays no role in whether those making investment decisions will opt for wind power production on land or offshore; the crucial factor will be the technical and economic feasibility of the investments. In addition, the current shipping lanes were taken into account in the area designations. 

The impacts of offshore wind power plants on human living environments comprise the visual disturbance and noise created by the turbines. The exposure to these nuisances may affect coastal residents, holiday houses, recreation areas and boating. However, the areas designated for offshore wind power production in the Maritime Spatial Plan are mainly located far from settlement. Leisure boating usually also concentrates in areas with dense settlements or holiday housing. An effort has been made to take these factors into account in the planning by using models that also address the impacts of visual disturbance and noise, as well as the distance to holiday houses and permanent settlements in general. While vessel traffic in ports may increase during the construction phase, the normal operation of power plants would have little impact on human living environments.

Wind turbines have an impact on the structure, nature and quality of the landscape. The visual impacts, or the visibility of the wind power plants in the landscape, are highlighted due to the plants’ large size. As a theoretical maximum visibility area is regarded approx. 20 to 35 km from the power plants. This is the distance across which the plants can be detected with the naked eye in good weather conditions. In addition to the extent of the visible change caused by wind turbines, the landscape’s tolerance and values affect the significance of the impacts on landscape.[7]  The visual impacts of wind turbines are exacerbated by their movement and the flicker effect. In addition, the location selected for wind turbines in the landscape is highlighted in areas with no other light sources.[8]

The potential areas designated for offshore wind power production in the Maritime Spatial Plan are mainly located in the open sea and partly as a wedge widening towards the open sea. As a rule, the distances between the power plants closest to the coast and the nearest islands or shoreline areas on the mainland would be long, and the impacts on landscape would be minor. Despite this, wind farms may have an impact on the nature of landscape complexes. In areas modified by human activity, the change in the nature of a landscape complex caused by a wind farm typically is smaller than in areas with little or no human activity.18 So far, the level of visible and permanent human activities carried out in the offshore areas is low, and the marine landscape is mainly seen as a natural one. Locating offshore wind farms in the open sea will change the natural landscape into a landscape shaped by human activities. This may erode the recreational value of the landscape, especially when observed from shore and sea areas in a pristine state. Particularly in terms of nature tourism, changes to the landscape caused by wind farms may have local negative impacts, whereas wind farm sites may be potential destinations for industrial tourism. The sites suitable for wind power production are mainly located so far away from the archipelago with its valuable landscapes and built cultural environment sites that their landscape-related impact on cultural heritage is minimal.

The potential sites for offshore wind farms only cover a small part of Finland’s marine areas, and the open landscapes of these areas would mainly be preserved. Additionally, only some of the designated sites can actually be used. The locations of potential sites for wind farms vary in different marine areas, and in some areas, the overall impacts on the landscape may be significant, especially taking into account the combined effects of the projects planned offshore and the projects implemented and planned on the mainland.

For the part of cultural heritage, the construction of foundations for offshore wind power plants and power transmission cables may have negative impacts on underwater cultural heritage sites and cultural environments of the archipelago and the coast. The building of new offshore wind farms may increase the knowledge of underwater cultural heritage sites, thus promoting the preservation of this heritage.

Offshore wind farms have negative impacts on the Defence Forces’ sensors providing situational awareness of the air and sea by creating blind spots that can prevent the full monitoring of the airspace and territorial waters. A statement from the Defence Forces should thus be requested on any negative impacts created by planned wind farm projects.[9]