Impact Of Offshore Wind Farms Research Articles

Effects of established offshore wind farms on energy flow of coastal ecosystems: A case study of the Rudong offshore wind farms in China

To assess the impact of offshore wind farms (OWFs) on the structure and energy flow of coastal ecosystems, Ecopath models of the Jiangsu coastal ecosystem (JCE) based on biological field data collected before and after the establishment of the Rudong OWFs in 2007 and 2015, respectively, were constructed and compared. The results indicated that after OWF construction, detritus, phytoplankton, zooplankton, anchovies, and some benthic fish were positively impacted. The increased primary production and detritus resulted in the increased food supply for zooplankton, which made it possible for planktivorous species (particularly anchovies) to be fed. Consequently, the biomass and production of some benthic fish increased, which indicates a potential reef effect. Other groups with decreased biomasses and productions may have been negatively impacted by the OWFs. Herbivory flows dominated the pre- and post-construction JCE despite their low transfer efficiencies; however, the proportion of detritivory flow increased after OWF construction, and this was especially prominent at high trophic levels. The post-construction JCE was immature with lower system connectivity, trophic flow utilisation, and transfer efficiency. However, the ecosystem tended to develop towards higher maturity with higher energy throughput, ecosystem activity, and recycling capability.

An ecosystem approach for studying the impact of offshore wind farms: a French case study

Abstract The French government is planning the construction of offshore wind farms (OWF) in the next decade (around 2900 MW). Following the European Environmental Impact Assessment Directive 85/337/EEC, several studies have been undertaken to identify the environmental conditions and ecosystem functioning at selected sites prior to OWF construction. However, these studies are generally focused on the conservation of some species and there is no holistic approach for analysing the effects arising from OWF construction and operation. The objective of this article is to promote a sampling strategy to collect data on the different ecosystem compartments of the future Dieppe-Le Tréport (DLT) wind farm site, adopting an ecosystem approach, which could be applied to other OWFs for the implementation of a trophic network analysis. For that purpose, an Ecopath model is used here to derive indices from Ecological Network Analysis (ENA) to investigate the ecosystem structure and functioning. The results show that the ecosystem is most likely detritus-based, associated with a biomass dominated by bivalves, which could act as a dead end for a classic trophic food web since their consumption by top predators is low in comparison to their biomass. The systemic approach developed for DLT OWF site should be applied for other French and European installations of Offshore Wind Farm.

Dodging the blades: new insights into three-dimensional space use of offshore wind farms by lesser black-backed gulls Larus fuscus

GPS telemetry is improving our understanding of the way animals interact with their environment. Recent research has used this technology to assess the impact of offshore wind farms (OWFs) on seabirds, but few studies have collected fine-scale data from birds flying within OWFs. We use GPS telemetry to investigate movements of lesser black-backed gulls Larus fuscus in relation to OWFs from a protected site with an active breeding colony. Individual birds varied considerably in their use of OWFs; 15 out of 24 birds visited them, and time spent in these areas was 1.3% of time budgets across all birds. Two birds, for which the most data was collected, frequently entered OWFs and flew at turbine blade height; however, their overlap with the spherical 3-dimensional rotor swept volume was significantly lower than a random distribution. Although preliminary, these tracking data suggest a lack of a macro-scale (wind farm-scale) avoidance for L. fuscus but a potential meso-scale (within wind farm-scale) avoidance of turbines. Such data are therefore important in improving our understanding of the implications of OWFs for seabirds.

Modelling the impact of offshore wind farms on safety radars onboard oil and gas platforms

Offshore oil and gas (O&G) platforms and subsea assets are often protected by radar early warning systems (REWS). Offshore wind farms can be located within few nautical miles from offshore O&G assets. Wind farms can interfere with the REWS due to their large and varying returns. The REWS's performance can also be affected by the radar shadows from turbines. This study aims to introduce REWS and its basic operation. It will then highlight some of the key parameters which must be considered when modelling the potential interference of wind farms on REWS. This study will also present some modelling result for a generic wind turbine's nearfield scattering, simplified shadowing effects and the impact of turbines return on the detection threshold. Finally, a realistic scenario is considered and modelled to show the potential adverse effects of the wind farm on the detection of vessels travelling within the wind farm region.

Method to estimate the visual impact of an offshore wind farm

The objective of this paper is to introduce a method that quantifies the degree of visibility of an offshore wind farm from an observer located along the coast. Due to the relative vicinity with living areas, the installation of an offshore wind farm leads in many cases to public opposition. Therefore, there is still a need to provide planners and decision makers appropriate methods and objective criteria to actually evaluate the visual impact of offshore wind farms. The aim is to provide an intelligible method for visual assessment that can be applied and used within a full decision-aid system oriented towards offshore wind turbines. A visual operator that takes into account the visual distance of an observer located on the ground to the farms layout is introduced. Such operator is based on the aggregation of three different indexes. The horizon occupation is the main index, it evaluates the horizon surface impact. This parameter is modulated by a second index that computes the number of distinguishable turbines and a third index considered as an aesthetic one based on turbine alignments. The whole method is implemented on top of a Geographical Information System (GIS). Overall, the approach provides an estimation of the visual impact without further need for local surveys, it is conceived as a decision-aided mechanism oriented to decision-makers and that can be used at the preliminary steps of the study of an offshore wind farm. The whole approach is experimented in the context of a wind farm in North West France.

The impact of offshore wind farms on beach recreation demand: Policy intake from an economic study on the Catalan coast

Offshore wind energy development can have major economic implications because of the potential impact on coastal recreation demand – particularly for countries that are characterised by high offshore wind power potential while also being popular tourist destinations. In this context, the impact of offshore wind farm projects on beach recreation demand in Catalonia (Spain) during the 2012 summer season was examined. A combined revealed and stated preference approach, which allows joint modelling of actual and hypothetical demands, was applied. The results demonstrate a significant welfare loss up to €203 million per season. The results further show that the installation of a wind farm mainly will cause a shift in trips to Catalan beaches without wind farms, which implies that the estimated negative economic impacts will occur mostly in areas where wind farms are located. From a political economy point of view, this may call for the design and implementation of re-distributive instruments to offset the negative impacts caused by wind farms.

Density dependence and marine bird populations: are wind farm assessments precautionary?

Summary Although density‐dependent regulation of population growth is thought to be relatively widespread in nature, density‐independent models are often used to project the population response to drivers of change. Such models are often considered to provide a maximum estimate of mortality and therefore offer a precautionary approach to impact assessment. However, this perception assumes that density dependence operates as compensatory (negative density dependence), and overlooks that other forms of density dependence, such as depensation (positive density dependence), would generate a contrasting population response. Currently, there is debate about including density‐dependent mechanisms in models that assess the impact of offshore wind farms on marine bird populations. Density dependence is considered poorly understood for this group of species. Consequently, it is either excluded from assessments, or incorporated in a compensatory form that has little empirical validation. We reviewed the evidence for compensatory and depensatory regulation of 31 marine bird species, and conducted a meta‐analysis to examine the functional shape of density‐dependent population growth. The evidence was also evaluated in relation to established species‐specific indices of wind farm vulnerability in order to assess whether compensatory mechanisms are likely to offset losses associated with collision or displacement. Compensatory regulation was reported across all of the demographic processes and focal groups considered, and was attributed to a variety of causal mechanisms. The strength of compensatory population growth appeared consistent between colonies; however, the regulation of productivity was highly context‐dependent with a similar number of studies reporting compensatory, depensatory and insignificant effects. Depensation was consistently attributed to increased rates of predation at lower population densities. Synthesis and applications. We conclude that among marine bird species with high vulnerability to wind farms, compensatory regulation is unlikely to offset large and sustained losses from the breeding population. In addition, depensation has the potential to accelerate population declines and generate local or regional extinctions, especially in smaller colonial species. Consequently, density‐independent models will not offer a consistently precautionary approach for assessing the potential impact of wind farms on marine bird populations. Instead, assessments should examine the potential population response using a range of density‐dependent structures.

Possible impacts of offshore wind farms on seabirds: a pilot study in Northern Gannets in the southern North Sea

We studied the impact of offshore wind farms on the distribution of Northern Gannets in the southern North Sea. Distributions were derived from ship-based and aerial-transect counts, and from global positioning system (GPS) tracking of chick-rearing adults from the colony on Helgoland. Foraging trips of tagged Gannets lasted from 0.4 to 53.5 h, with a total distance flown per trip of 4.7–937.9 km, and range of 2.0–320.8 km. Gannets largely avoided the wind farm area north of Helgoland. This avoidance behaviour implies that, although Northern Gannets may not be killed by rotor blades, they may experience substantial habitat loss. GPS tracking is well suited to the study of wind farm effects on birds and possible habituation processes at the individual level.

Quantifying the impact of offshore wind farms on Gannet populations: a strategic ringing project

Given the conservation importance of Gannet populations in Britain, and concerns about possible adverse impacts of offshore wind farms on Gannets as a result of collision risk, we advocate the establishment of strategic monitoring studies at key colonies. Colour ringing adult Gannets to measure survival at colonies close to and distant from offshore wind farms could indicate whether or not collision mortality has a detectable effect on adult survival. Colour ringing chicks could provide information on prospecting movements of immatures and colonies where birds recruit. Tracking studies of both adults and immatures would be highly desirable to complement improved monitoring of demography.

Turbid wakes associated with offshore wind turbines observed with Landsat 8

In the last decade, the number of offshore wind farms has increased rapidly. Offshore wind farms are typically constructed in near-shore, shallow waters. These waters can be highly productive or provide nursery grounds for fish. EU legislation requires assessment of the environmental impact of the wind farms. The effects on hard and soft substrate fauna, seabirds and marine mammals are most frequently considered. Here we present Landsat-8 imagery that reveals the impact of offshore wind farms on suspended sediments. Turbid wakes of individual turbines are observed that are aligned with tidal currents. They are 30–150m wide, and several km in length. The environmental impact of these wakes and the source of the suspended material are still unclear, but the wake size warrants further study. The underwater light field will be affected by increased suspended sediments and the turbid wakes could significantly impact sediment transport and downstream sedimentation. The question of whether such features can be detected by other remote sensors is addressed by a theoretical analysis of the signal:noise specification for the Operational Land Imager (OLI), the Enhanced Thematic Mapper Plus (ETM+), the Advanced Very High Resolution Radiometer (AVHRR/3), the Moderate-Resolution Imaging Spectroradiometer (MODIS), the Spinning Enhanced Visible and Infrared Imager (SEVIRI), the Flexible Combined Imager (FCI) and the Multispectral Instrument (MSI) and by a demonstration of the impact of processing OLI data for different spatial resolutions.

Migration strategies of the Yelkouan Shearwater Puffinus yelkouan

Although the Yelkouan Shearwater Puffinus yelkouan is listed as near threatened on the International Union for Conservation of Nature Red List, with many populations in serious decline, there is little detailed information on the location of its key foraging areas during the non-breeding season. To address this knowledge gap, adult Yelkouan Shearwaters at a breeding colony in Malta were fitted with geolocators in 2 consecutive years. Of the 13 birds tracked (two of which were tracked in both years), the majority (n = 10; 76.9 %) migrated in June–July to spend most of the non-breeding period in the Black Sea (n = 5), Aegean Sea (n = 2), Black and Aegean seas (n = 2), or Black and Adriatic seas (n = 1). The final three birds remained within the central Mediterranean area and did not move beyond 500 km of the breeding colony. There was considerable variation among individuals in terms of timing of the outward and return migrations, duration and location of periods of residency in different areas, and migration routes. However, migration patterns (including routes and areas visited) were very consistent in the two individuals tracked in consecutive years. All birds returned in November or December to waters closer to the breeding colony, concentrating between the North African coast and the southern Adriatic. This study has identified key areas during the non-breeding season for Yelkouan Shearwaters from Malta which are also likely to be important for other populations. Given the continuing decline of this species throughout its range, this information represents an essential step for improving international conservation efforts. At-sea threats in the wintering regions include by-catch in long-line and trawl fisheries, impacts of over-fishing, illegal hunting (particularly in Maltese waters), ingestion of plastics, pollution, and the potential impact of off-shore wind farms. These threats need to be addressed urgently in the areas identified by this study to prevent further declines.

The case for offshore wind farms, artificial reefs and sustainable tourism in the French mediterranean

As the French government strives to achieve their offshore renewable energy target, the impact of offshore wind farms on coastal tourism in the Languedoc Rousillon is now being questioned. To assess this issue, a choice experiment was undertaken to elicit tourist preferences for wind turbines at different distances from the shore. We also examined whether potential visual nuisances may be compensated by wind farm associated reef-recreation or by adopting a coherent environmental policy. The findings indicate that age, nationality, vacation activities and their destination loyalty influence attitudes towards compensatory policies. Two policy recommendations are suggested. First, everything else being equal, wind farms should be located no closer than 12 km from the shore. Second, and alternatively, a wind farm can be located from 5 km and outwards without a loss in tourism revenues if accompanied by a coherent environmental policy and wind farm associated recreational activities.

Environmental impact assessment of offshore wind farms: a simulation‐based approach

Summary 1. Assessing and monitoring the impact of offshore wind farms on marine fauna is vital if we want to achieve ecologically sustainable development of this renewable energy resource. Given the complexity of the marine environment, a method capable of accommodating spatio‐temporal behaviour of specific species and their interrelation with other marine phenomena is an essential prerequisite for investigating whether or not there has been any measurable impact to date. 2. This paper presents a method based on geostatistical simulation to assess whether pre‐ and post‐construction collected bird count data suggest displacement of birds due to the wind farm. The method takes into account spatial autocorrelation in species abundance at various scales, pre‐ and post‐construction differences in environmental conditions and in survey effort and design. 3. We demonstrate that taking these factors into account influences the conclusions about a wind farm’s impact on bird life. In particular, incorporating spatial autocorrelation in seabird numbers is an important factor in reducing the risk of wrongly identifying an effect of a wind farm on bird abundance. 4. Synthesis and applications. The development of offshore wind farms is often in conflict with nature conservation interests. Environmental impact assessment and monitoring is essential to protect and manage the marine environment. The method described here will allow scarce data to be utilized effectively as a basis for well‐informed environmental decisions. In addition, the method will assist in the design of optimal monitoring procedures at a given site, balancing costs and effectiveness in detecting potentially harmful impacts.

Assessing the responses of coastal cetaceans to the construction of offshore wind turbines

The expansion of offshore renewables has raised concerns over potential disturbance to coastal cetaceans. In this study, we used passive acoustic monitoring to assess whether cetaceans responded to pile-driving noise during the installation of two 5MW offshore wind turbines off NE Scotland in 2006. Monitoring was carried out at both the turbine site and a control site in 2005, 2006 and 2007. Harbour porpoises occurred regularly around the turbine site in all years, but there was some evidence that porpoises did respond to disturbance from installation activities. We use these findings to highlight how uncertainty over cetacean distribution and the scale of disturbance effects constrains opportunities for B-A-C-I studies. We explore alternative approaches to assessing the impact of offshore wind farm upon cetaceans, and make recommendations for the research and monitoring that will be required to underpin future developments.