Coastal and Offshore Wind Energy Generation: Is It Environmentally Benign?


Windkraftanlagen an der dänischen Küste in Bønnerup Strand. Creative commons image credit: Dirk Goldhahn

Jennifer C. Wilson, Mike Elliott, Nick D. Cutts (University of Hull ) and the co-authors listed in the citation have published a new paper analyzing the environmental benefits (and risks) associated with coastal and off-shore wind energy generation.  The abstract to this paper: Offshore and coastal wind power is one of the fastest growing industries in many areas, especially those with shallow coastal regions due to the preferable generation conditions available in the regions. As with any expanding industry, there are concerns regarding the potential environmental effects which may be caused by the installation of the offshore wind turbines and their associated infrastructure, including substations and subsea cables. These include the potential impacts on the biological, physical and human environments. This review discusses in detail the potential impacts arising from offshore wind farm construction, and how these may be quantified and addressed through the use of conceptual models. It concludes that while not environmentally benign, the environmental impacts are minor and can be mitigated through good siting practices. In addition, it suggests that there are opportunities for environmental benefits through habitat creation and conservation protection areas.

The introduction to this good paper reads:

Environmentalists and environmental managers increasingly debate the installation of offshore wind generating capacity because of its current position as the most rapidly expanding sector of the renewable energy industry. These installations are increasing, for example in the UK, with the largest of the recent Round 3 zones, announced in January 2010, being over 8,600 km2 (see The Crown Estate website for further details ( The potential for energy yield is greater at sea than an equivalent wind farm on land and, with technological advances, the capacity to install turbines and their associated infrastructure further and further offshore is becoming achievable, allowing access to even greater and more constant winds and energy yields. The move offshore also minimises public disturbance, overcoming objections to onshore wind farms due to the noise and visual impacts the structures.

The UK, for example, will rapidly increase the number of planned and operational wind farms in the near future. Using the latest turbine technology, the installation of 2,000 onshore and 1,500 offshore turbines should enable the UK government to achieve its 2010 energy targets. Turbine design continues to develop, with larger and/or more efficient designs, e.g., 10 MW turbines are planned, such that generative capacity predictions and turbine numbers will increase in future.

Given these developments, there is the need to rigorously identify the environmental consequences of this activity. All human activities are required to have an environmental appraisal as they are assumed to have an environmental impact unless the developer can conclusively demonstrate otherwise. Hence a critical element in the development phase of an offshore wind farm is the Environmental Impact Assessment (EIA). At its best, an EIA should be simple—it is ‘what is the effect of this activity, at this place, at this time, carried out in this way, and how do we mitigate or compensate for any effect identified’. It is not a ‘helicopter survey’ (i.e. an academic exercise in which every aspect is studied irrespective of the probability of an effect by the development being detected. It should be a relatively straightforward process—to distinguish for any impact between substantial, moderate and slight according to the magnitude of impact itself, to assess the value and sensitivity of receiving landscape, and the sensitivity of the ‘potential receptors’. It should not be an unwieldy and excessively time consuming assessment of every component of the receiving area in which the output is measured by the size of the Environmental Statement (ES) (the resulting report of the EIA process). The EIA process should be a rigorous separation of the various phases of the project: pre-construction, during construction/pre operation, post-construction/during operation, post-operation/ during decommissioning. There is the risk, in the EIA process, of making it too detailed, resulting in the presentation of too-detailed information, making the decision-making process not simpler, but more complicated than necessary.

This review aims to analyse the potential environmental impacts and benefits of an offshore wind farm, put them into context, and show the potential dangers of making the EIA more detailed than required. As with any activity of the scale of an offshore wind farm, there is the potential for impacts to occur within the local and surrounding environment. For ease, these may be divided into the four main sections of development. Firstly, exploration may involve installing a meteorological mast; undertaking geophysical surveys, initial surveys of the ecology of the area and other studies of the baseline environment and physical situation of the location, to determine suitability for development.

During construction, depending on the foundations used for the development, monopile foundations may be driven or drilled into the seabed, or gravity bases placed on the surface of the seabed. The installation of sub-sea cables, and the presence of additional vessels in the area may also have an impact. In contrast, the operational phase of the wind farm is perhaps the phase with the least potential for impact, as once the structures are in place, maintenance for the projects is generally minimal where possible. Decommissioning of the project may have many of the impacts of construction, although possibly slightly less if sub-sea structures are left in situ once decommissioned.

Within all phases, the main potential threat to the surrounding environment is the disruption of natural processes, with the further potential to impact ecological functioning in the area. Therefore, we need to consider what components are affected and by what magnitude, and thus the links to ecosystem structure. Examples of interference with such processes are impeding migration routes and currents and thus sediment dispersal mechanisms. With the installation of new hard structures into the environment however, there is the potential for the foundations to act as artificial reefs, thereby creating habitat in place of that which is unavoidably lost through their installation. These new pockets of habitat can then act as stepping stones for colonisation, allowing the spread of both existing and new species across the area.

As with all projects, especially those of such a scale, monitoring elements of the project over its lifetime is a key way of identifying whether those impacts which were originally predicted did occur and, if so, did they occur to the extent originally anticipated. This not only increases the body of knowledge as to how structures such as offshore wind turbines interact with their environment, but can also feed into future EIAs, enhancing their value for future projects.

As with any marine activity, it is necessary to separate the effects into those which are unlikely, possible, probable and certain; given that we have a long history of putting structures into the environment, then there is a long case-history on which to base our assessments. There has to be a robust means of defining and quantifying an impact but, within a highly dynamic and variable system, of defining and detecting a defendable ‘signal to noise ratio’ and at the same time keeping the methods and effort of detection of effect in proportion. Hence the assessment has to include the air, water, sediment and their interfaces and in turn the effects on marine landscapes.

Offshore wind power has been described as a fledgling industry, and as such there was an initial suggestion in the UK that it should be treated gently while at the same time treated with rigour. Even early on, its consequences were described by NGOs as being ‘environmentally benign’. However, although we have a long history of understanding marine and estuarine activities, while there is an increasing number of EIA and ES for new schemes, as yet (if it ever occurs) there is little post-construction auditing, and we need to learn more from past experience. Thus there is the need to determine whether all elements of the EIA were needed, was there any non cost-effective (or even wasteful) monitoring and were the predictions of impact correct. It is of note that there is still a lot of qualitative prediction but also the need for post-operation monitoring to increase our confidence in assessments.

As a starting point and a means of both producing a logical sequence and communicating the potential for change to all audiences, all assessments of potential impacts of marine activities require a conceptual model. While it is easy to create such models (referred to here as ‘horrendograms’) it is more difficult to determine the significance of the effects against the perceptions of change. Hence there is the need to differentiate the important features of change from the less important or even unlikely ones.

Read the full article in PDF format by clicking here.

Citation: Wilson, J.C.; Elliott, M.; Cutts, N.D.; Mander, L.; Mendão, V.; Perez-Dominguez, R.; Phelps, A. Coastal and Offshore Wind Energy Generation: Is It Environmentally Benign?. Energies 2010, 3, 1383-1422.

2 Responses to “Coastal and Offshore Wind Energy Generation: Is It Environmentally Benign?”
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  1. […] the original here:  Coastal and Offshore Wind Energy Generation: Is It Environmentally … By admin | category: University of HULL | tags: citation, co-authors-listed, elliott, […]

  2. […] This post was mentioned on Twitter by Richard Walthers, Chattertrap Climate. Chattertrap Climate said: Coastal and Offshore Wind Energy Generation: Is It Environmentally Benign? #climate […]

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