Offshore Wind: Ecologists Tip-Toe into the Negatives

By Robert Bradley Jr. -- August 23, 2022

“Among the 867 findings extracted from the analysed publications [regarding offshore wind], 72% reported negative impacts, while 13% were positive.”

“The progressive expansion of OWFs [Offshore Wind Farms] to meet energy production objectives, including floating devices in deeper areas and farther offshore, faces relevant technical, economic, social, and ecological concerns worldwide.”

– “Reviewing the Ecological Impacts of Offshore Wind Farms,” npj Ocean Sustainability (2022).

Deep ecologists and rank-and-file environmentalists should shudder at the thought of industrial wind turbines talking over the coastal waters. The massive structures and electric cables to shore are bad enough. But the machinery’s low average-capacity factors and susceptibility to bad weather make for a very risky economic/ecological deal.

But economics scarcely matters to the Church of Climate. Carbon dioxide and fossil fuels are always worse. Anyway, the higher the electricity rates, the better, except for the optics and politics of it all. The enemy is just about every power generation source, after all.

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There is backdoor concern about offshore wind in the Church. “We’re exiting one poorly considered and hastily implemented energy technology,” the climate alarmist site Skeptical Science commented.

Now we know better. This article is what judicious, circumspect adoption of newer & better systems looks like. Better doesn’t mean perfect, better can be done worse or better. 

The referenced article is Reviewing the ecological impacts of offshore wind farms (npj Ocean Sustainability: 2022). Quotations follow:

• … current expectations for the expansion of energy production from offshore wind may lead to significant environmental impacts. Assessing ecological risks to marine ecosystems from electricity production from wind is both timely and vital.
• Renewable energy production growth should not lead to significant environmental harm nor compromise environmental objectives, and new projects must be compatible with biodiversity protection and conservation objectives….
• When developing plans for a new industry such as offshore renewables, there may be interactions between devices and marine species or habitats that regulators and stakeholders perceive as risky, as there are still considerable gaps in scientific knowledge about the ecological impacts of wind turbines.
• There is thus an urgent need to identify and assess potential environmental impacts associated with offshore energy production in order to prevent or minimize negative effects at a very early stage of the OWE planning process.
• A total of 867 findings on pressures due to wind energy devices and impacts on ecosystem elements were extracted from 158 publications…. Half of the analysed publications (51%) presented empirical evidence, while 36% of the studies were based on modelling approaches, including the modelled propagation of underwater noise….
• Most studies investigated single pressures, with few papers addressing the interaction of two or more pressures produced by wind energy devices…. This represents a shortcoming in the analysis of wind energy devices impacts, since it is well-known that human activities can produce several co-occurring pressures, which can result in cumulative, synergistic or antagonistic impacts on the ecosystem.
• Investigating multiple interactions between human activities and ecosystem elements is urgent, given that future wind energy developments will add to the cumulative impacts already produced by existing activities and climate change. Additionally, due to the expected increased demand for marine space, multiple ocean uses are likely to take place in the same area as OWE activities and an increase of local cumulative pressures is likely to happen.
• Offshore energy production can have both positive and negative impacts on marine ecosystems. Negative impacts are reported more frequently (up to 10% of the scientific findings) being especially linked to birds, marine mammals, and ecosystem structure. Positive effects are less reported (up to 1% of scientific findings), relating mostly to fish and macroinvertebrates.
• The ecological risks derived from the negative impacts of wind energy devices can vary biogeographically, depending on the environmental characteristics and vulnerability of the affected area (e.g., presence of migrating bird species especially sensitive to wind turbines). The identification of potential significant impacts is, therefore, always case-specific.
• In particular, the real impact of an OWF on protected species and habitats will show high spatial variability; it must be carefully assessed with respect to local conservation objectives and the affected species/habitats. Furthermore, environmental impacts will also depend on the initial state and resilience of the area, which can change dramatically for some ecosystem elements.
• Indirect impacts, which tend not to be fully investigated, must also be considered. Increases in prey species (e.g., pressure tolerant) at OWFs will increase food availability to higher trophic levels (e.g., bird and mammal species), thereby increasing their populations. Impacts will thus vary among species within the same ecosystem element (e.g., different seabird species may be affected in different ways by turbines).
• In some cases, impacts may be positive (e.g., seabirds have rest areas and more resources for food), while in others, species may suffer significant adverse effects impacting their behavior. Impacts may spread far from the OWF area (e.g., lower number of organisms of migratory populations at the final destination), as is the case for land-based wind farms.
• It is … fundamental to consider the spatial and temporal distribution of the most sensitive species when determining the risks associated to a given project. For the adoption of such an approach, better data is required on species distribution and abundance over annual cycles and on the migration routes of birds, fish, and marine mammals.
• Despite the evident negative impacts of OWFs on ecosystem elements, potential positive impacts must also be highlighted. According to several authors, positive environmental impacts are linked to reserve and reef effects on the area of OWF deployment and mooring structures. These can function as artificial reefs and fish aggregation devices for small demersal fish, attracting more marine life than natural reefs.
• … with the expected global expansion of OWFs projects to new areas, impacts on temperate, subtropical, and tropical species must be further investigated. While disturbance of high taxonomical levels is important (i.e., mammals, seabirds, fish), physical loss and physical disturbance of benthic habitats needs to be investigated in detail, as large OWF developments and the high density of wind turbines may hinder the achievement of good environmental status for biodiversity or seafloor integrity.
• Among the 867 findings extracted from the analysed publications, 72% reported negative impacts, while 13% were positive. Regarding impact magnitude (either positive or negative), 54% were reported as being high or moderate, while low or negligible impacts accounted for 32%.
• …the impact type of ‘biological disturbance’ pressure (row 1) over ecosystem element ‘birds’ (column 5) is mostly reported as being negative. There is also a high degree of scientific consensus.
• The relatively high degree of agreement regarding impact type (e.g., positive, negative) of wind devices on ecosystem elements is noteworthy. By contrast, certainty regarding impact magnitude is relatively low, especially for marine mammals and ecosystem structure, functions, and processes. This highlights the lack of empirical evidence needed to assess impact magnitude and, hence, the full ecological risks associated with OWFs.
• For all ecosystem components together, high-moderate negative impacts accounted for 45% of the findings, 32% of which referred to effects on birds. Negative impacts are associated with changes in bird abundance due to collision mortality and displacement, changes in distribution patterns, and alteration of behaviour to avoid OWFs.
• Species differed greatly in their sensitivity to pressures, with different responses depending on their ecology (i.e., flight altitude, season, sex). In turn, only 1% of the findings reported high-moderate positive impacts on birds (e.g., attraction behaviour toward OWFs by gulls or cormorants).
• As for marine mammals, up to 7% of the findings referred to negative impacts, depending on the OWF development phase. Pile driving can have a significant impact on mammal’s abundance and distribution (e.g., avoidance behaviour with porpoises temporarily leaving the construction area). By contrast, 0.5% of the findings reported positive effects.
• In what regards fish, over 2% of the findings reported high-moderate negative impacts. The magnitude of such impacts depends on the affected species and its level of vulnerability/sensitivity, with potentially more severe effects for elasmobranchs. The same percentage of findings reported high-moderate positive impacts related to shelter (against currents and predators) and food availability, stimulating aggregation behaviour. OWFs may act as fish aggregation devices, with spill-over effects. Fish species from rocky environments were more abundant close to OWFs than those from sedimentary environments.
• One of the most relevant non-technical barriers affecting the expansion of the offshore renewable energy sector is the potential environmental risk (and related uncertainties). The latter entails significant repercussions in the promptness of the consent process and associated economic costs.
• The progressive expansion of OWFs to meet energy production objectives, including floating devices in deeper areas and farther offshore, faces relevant technical, economic, social, and ecological concerns worldwide. Among other challenges, it will add to and be affected by the increasing demand for ocean space. Interactions with other traditional and strategic human uses of the ocean need to be considered in order to avoid, or at least minimise, spatial conflicts.

Caveat (forgiveness)

• This review is not intended to question the potential of OWF production as a credible source of clean and renewable energy, with its direct and indirect economic, social, and environmental benefits. Instead, it intends to highlight the potential ecological effects that the sector’s expansion will cause at local and regional scales. While legislation to reduce local impacts of OWF is necessary, it must be proportionate and weighed against the global environmental, social, and economic benefits that derive from reducing fossil-fuel emissions.