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May 8, 2014

Marine Industry: Offshore Renewable Energy

Reviews

  • Melo, A.B., Sweeney, E., and Villate, J.L.  Global review of recent ocean energy activities.  Marine Technology Society Journal 47(5): 97-103, 2013.  
    Read Abstract >>

    Ocean energy is regarded as an important future source of energy generation in many countries for transition to a low-carbon future. While commercial interest in ocean energy is growing significantly at a global level, there are considerable investment costs and bottlenecks that will need to be overcome. Research and funds are spread over many different wave and marine current energy concepts under development, and there is still no technology convergence, in contrast to what happened in wind energy. Although an important marine energy resource, discussion of offshore wind energy is not included in this manuscript. This article focuses on the latest developments in ocean energy - in particular, open-sea testing facilities set up by several countries as a measure to encourage deployment and streamlining procedures - and gives an overview of projects going into the water this past year. In addition, the article highlights the importance of collaborative research and development on ocean energy projects and the unique role of the Ocean Energy Systems Implementing Agreement as an intergovernmental organization promoting the use of ocean energy (wave, marine currents, tidal, ocean thermal gradients and salinity gradients) for energy extraction.

  • James, V.  2013.  Marine Renewable Energy: A Global Review of the Extent of Marine Renewable Energy Developments, the Developing Technologies and Possible Conservation Implications for Cetaceans.  Whale and Dolphin Conservation, Chippenham, Wiltshire, UK.  122 pp.
    Open Access >>
    Read Abstract >>

    This report provides here is an overview of the present extent of the wave, tidal and wind energy developments across the globe as of February 2013, the technology involved and the consideration of how they may affect cetaceans. Recommendations are made towards ensuring that cetaceans are adequately considered early when strategically planning these developments and offered suitable protection as a result.

  • Rajagopalan, K. and Nihous, G.C.  Estimates of global Ocean Thermal Energy Conversion (OTEC) resources using an ocean general circulation model.  Renewable Energy 50: 532-540, 2013.   
    Read Abstract >>

    Global Ocean Thermal Energy Conversion (OTEC) resources are assessed for the first time with an ocean general circulation model (OGCM). Large-scale OTEC operations are represented with fluid sources and sinks of prescribed strength in global (4° x 4°) MITgcm simulations. Preliminary steady-state (time-asymptotic) results show similarities, but also significant differences with earlier one-dimensional (1-D) studies. It is confirmed that global OTEC resources are likely limited by OTEC flow effects on the stability of the vertical oceanic thermal structure. Such a limit is several times greater in a full three-dimensional context, however, with an estimated maximum annual OTEC net power production of about 30 TW. The significant OTEC flow rates corresponding to maximum net power output would result in a strong boost of the oceanic thermohaline circulation (THC). In contrast to simple 1-D analyses, the present simulations of large-scale OTEC operations also show a persistent cooling of the tropical oceanic mixed-layer. This would be balanced by a warming trend in the higher latitudes, which may practically limit OTEC deployment to smaller flow rates than at maximum net power output. An annual OTEC net power production of about 7 TW, for example, could be achieved with little effect on the oceanic temperature field.

  • Sullivan, R.G., Kirchler, L.B., Cothren, J., and Wintersm, S.L.  Offshore wind turbine visibility and visual impact threshold distances.  Environmental Practice 15(1): 33-49, 2013.
    Read Abstract >>

    Potential visual impact on coastal lands has emerged as a major concern in the development of offshore wind facilities in the United States and Europe. Optimal siting of offshore facilities requires accurate knowledge of the relationship between distance and the visibility of wind turbines. Past assessments of offshore wind turbine visibility were based on smaller turbines and facilities in use at the time and underestimate visibility for current projects, which use more and larger larger turbines. This study is a preliminary assessment of the visibility of offshore wind facilities in the United Kingdom. Study objectives included identifying the maximum distances the facilities could be seen in both daytime and nighttime views and assessing the effect of distance on visual contrasts associated with the facilities. Results showed that small to moderately sized facilities were visible to the unaided eye at distances greater than 42 km [26 miles (mi)], with turbine blade movement visible up to 39 km (24 mi). At night, aerial hazard navigation lighting was visible at distances greater than 39 km (24 mi). The observed wind facilities were judged to be a major focus of visual attention at distances up to 16 km (10 mi), were noticeable to casual observers at distances of almost 29 km (18 mi), and were visible with extended or concentrated viewing at distances beyond 40 km (25 mi).

  • Zheng, C.-w. and Pan, J.  Assessment of the global ocean wind energy resource.  Renewable and Sustainable Energy Reviews 33: 382-391, 2014.
    Read Abstract >>

    Against a background of an environmental and resources crisis, the exploitation of renewable and clean energy can effectively alleviate the energy crisis and contribute to emission reduction and environmental protection, thus promoting sustainable development. This study aims to develop a grade classification map of the global ocean wind energy resource based on CCMP (cross-calibrated, multi-platform) wind field data for the period 1988–2011. We also calculate, for the first time, the total storage and effective storage of wind energy across the global ocean on a 0.25°×0.25° grid. An optimistic increasing long-term trend in wind power density was found. In addition, the global ocean wind energy resource was analyzed and regionalized by considering the temporal and spatial distributions of wind power density, wind energy levels, and effective wind speed, as well as through a consideration of wind energy storage and the stability and long-term trends of wind power density. This research fills a gap in our knowledge in this field, and provides a reference point for future scientific research and development into wind energy resources such as wind power generation, water pumping, and wind-heating.

  • Tollefson, J.  Power from the oceans: blue energy.  Nature 508(7496): 302-304, 2014.
    Open Access >>
  • Ashley, M.C., Mangi, S.C., and Rodwell, L.D.  The potential of offshore windfarms to act as marine protected areas – A systematic review of current evidence.  Marine Policy 45: 301-309, 2014.
    Read Abstract >>

    As offshore windfarm (OWF) construction in the UK is progressing rapidly, monitoring of the economic and ecological effects of these developments is urgently needed. This is to enable both spatial planning and where necessary mitigation in an increasingly crowded marine environment. One approach to mitigation is co-location of OWFs and marine protected areas (MPAs). This systematic review has the objective to inform this co-location proposal and identify areas requiring further research. A limited number of studies addressing marine renewable energy structures and related artificial structures in coastal waters were found. The results of these studies display a change in species assemblages at artificial structures in comparison to naturally occurring habitats. An increase in hard substrata associated species, especially benthic bivalves, crustaceans and reef associated fish and a decrease in algae abundance were the dominant trends. Assemblages associated with complex concrete structures revealed greater similarity to natural hard substrata compared to those around steel structures. To consider marine renewable energy sites, especially large scale OWFs as MPAs, the dissimilar nature of assemblages on the structures themselves to natural communities should be considered. However positive effects were recorded on the abundance of commercially important crustacean species. This suggests potential for incorporation of OWFs as no fishing, or restricted activity zones within a wider MPA to aid fisheries augmentation. The limited available evidence highlights a requirement for significant further research involving long term monitoring at a variety of sites to better inform management options.

  • Copping, A., Smith, C., Hanna, L., Battey, H., Whiting, J., Reed, M., Brown-Saracino, J., Gilman, P., and Massaua, M.  Tethys: Developing a commons for understanding environmental effects of ocean renewable energy.  International Journal of Marine Energy 3-4: 41-51, 2013.
    Open Access >>
    Read Abstract >>

    A lack of consistent widespread information on potential environmental effects, monitoring outcomes, and mitigation strategies continues to hinder the development and deployment of marine energy systems around the world. To address this need, member nations of the Ocean Energy Systems (OES) formed Annex IV, a three-year collaborative effort (2010–2013) to increase knowledge sharing, research collaborations, and efficient regulatory decision-making associated with investigating and evaluating the potential impacts of wave and tidal energy. In parallel, the US Department of Energy began development of a publically-available, searchable online database of environmental information (called Tethys), housing scientific literature pertaining to the environmental effects of marine energy and offshore wind systems, as well as metadata on international ocean energy projects and research studies collected under Annex IV. In addition to providing broad access to information on environmental effects of marine energy and offshore wind developments, Tethys can act as a commons for bringing together researchers, device and project developers, regulators, and stakeholders, to explore shared interests and information needs for the emerging marine energy industry. This paper will demonstrate the development, existing functionality, and content of Tethys, as well as discuss the future of Annex IV including information updates, improvements, and additional outreach efforts over the next several years.

Prospects and Development

  • Makridis, C.  Offshore wind power resource availability and prospects: A global approach.  Environmental Science and Policy 33: 28-40, 2013.  
    Read Abstract >>

    In the absence of structural incentives that price negative externalities, renewable energies rely primarily on investors' expectations of future performance to succeed in the marketplace. While there have been many disparate regional analyses of the prospects for clean energy, in particular wind, there is yet a cohesive framework for thinking about global interactions. Using data from the National Renewable Energy Laboratory (NREL), the article addresses three shortcomings in empirical renewable policy literature. First, the article briefly synthesizes the current state of the offshore wind literature. Second, the article develops a linear programming model to assess the relative prospects of offshore wind energy throughout seven world regions: Organization for Economic Co-operation and Development (OECD) North America, OECD Europe, OECD Asia and Eurasia, Non-OECD Europe and Eurasia, Non-OECD Asia, Africa, and Central & South America. Third, the article applies the Interactive Agency Model (IAM) as a systems-level framework for thinking about offshore wind development in the presence of social, economic, and institutional attributes. Results suggest that OECD Asia and Eurasia, OECD Europe, and non-OECD Europe and Eurasia, respectively, have the highest potential for offshore wind sector performance. Despite simplifying assumptions, this article presents one of the first evaluations of global offshore wind energy potential for policymakers and industry to consider in crafting future renewable energy investment decisions.

  • Liu, T.Y., Tavner, P.J., Feng, Y., and Qiu, Y.N.  Review of recent offshore wind power developments in China.  Wind Energy 16(5): 786-803, 2013.
    Read Abstract >>

    Rapid wind power development in China has attracted worldwide attention. The huge market potential and fast development of wind turbine manufacturing capacity are making China a world leader in wind power development. In 2010, with the newly installed wind power capacity and the cumulative installed capacity, China was ranked first in the world. In 2009, China also constructed and commissioned its first large offshore wind farm near Shanghai. Following earlier papers reviewing the state of China's onshore wind industry, this paper presents a broader perspective and up-to-date survey of China's offshore wind power development, making comparisons between the developments in the rest of the world and China, to draw out similarities and differences and lessons for the China offshore wind industry. The paper highlights six important aspects for China's offshore wind development: economics, location, Grid connection, technological development, environmental adaptation and national policies. The authors make recommendations for mitigating some outstanding issues in these six aspects for the future development of China's offshore wind resource.

  • Dvorak, M.J., Corcoran, B.A., Ten Hoeve, J.E., McIntyre, N.G., and Jacobson, M.Z.  US East Coast offshore wind energy resources and their relationship to peak-time electricity demand.  Wind Energy 16(7): 977-997, 2013.   
    Read Abstract >>

    This study characterized the annual mean US East Coast (USEC) offshore wind energy (OWE) resource on the basis of 5 years of high-resolution mesoscale model (Weather Research and Forecasting–Advanced Research Weather Research and Forecasting) results at 90 m height. Model output was evaluated against 23 buoys and nine offshore towers. Peak-time electrical demand was analyzed to determine if OWE resources were coincident with the increased grid load. The most suitable locations for large-scale development of OWE were prescribed, on the basis of the wind resource, bathymetry, hurricane risk and peak-time generation potential. The offshore region from Virginia to Maine was found to have the most exceptional overall resource with annual turbine capacity factors (CF) between 40% and 50%, shallow water and low hurricane risk. The best summer resource during peak time, in water of £50 m depth, is found between Long Island, New York and Cape Cod, Massachusetts, due in part to regional upwelling, which often strengthens the sea breeze. In the South US region, the waters off North Carolina have adequate wind resource and shallow bathymetry but high hurricane risk. Overall, the resource from Florida to Maine out to 200 m depth, with the use of turbine CF cutoffs of 45% and 40%, is 965–1372 TWh (110–157 GW average). About one-third of US or all of Florida to Maine electric demand can technically be provided with the use of USEC OWE. With the exception of summer, all peak-time demand for Virginia to Maine can be satisfied with OWE in the waters off those states.

  • Kaldellis, J.K. and Kapsali, M.  Shifting towards offshore wind energy – Recent activity and future development.  Energy Policy 53: 136-148, 2013.
    Read Abstract >>

    To date, most of the existing wind farms have been built on-land but during the last few years many countries have also invested in offshore applications. The shift towards offshore wind project developments has mainly been driven by European energy policies, especially in north-west countries. In offshore sites the winds are stronger and steadier than on-land, making wind farms more productive with higher capacity factors. On the other hand, although offshore wind energy is not in its infancy period, most of the costs associated with its development are still much higher from onshore counterparts; however some recent technological progress may have the potential to narrow this gap in the years to come. In the present work, an overview of the activity noted in the field of offshore wind energy is carried out, with emphasis being given on the current status and future trends of the technology employed, examining at the same time energy production and availability issues as well as economic considerations.

  • Bahaj, A.S.  Marine current energy conversion: the dawn of a new era in electricity production.  Philosophical Transactions of the Royal Society A 371(1985): art. 20120500, 2013.
    Read Abstract >>

    Marine currents can carry large amounts of energy, largely driven by the tides, which are a consequence of the gravitational effects of the planetary motion of the Earth, the Moon and the Sun. Augmented flow velocities can be found where the underwater topography (bathymetry) in straits between islands and the mainland or in shallows around headlands plays a major role in enhancing the flow velocities, resulting in appreciable kinetic energy. At some of these sites where practical flows are more than 1 m s-1, marine current energy conversion is considered to be economically viable. This study describes the salient issues related to the exploitation of marine currents for electricity production, resource assessment, the conversion technologies and the status of leading projects in the field. This study also summarizes important issues related to site development and some of the approaches currently being undertaken to inform device and array development. This study concludes that, given the highlighted commitments to establish favourable regulatory and incentive regimes as well as the aspiration for energy independence and combating climate change, the progress to multi-megawatt arrays will be much faster than that achieved for wind energy development.

  • Allan, G.J., Lecca, P., McGregor, P.G., and Swales, J.K.  The economic impacts of marine energy developments: A case study from Scotland.  Marine Policy 43: 122-131, 2014.
    Open Access >>
    Read Abstract >>

    Delivering the ambitious renewable energy targets set by the Scottish Government will require significant expenditures. Plans have been set out to develop 1.6 GW of marine (wave and tidal) energy capacity between 2010 and 2020 in the Pentland Firth and Orkney Waters area (off the north coast of Scotland) with construction costs estimated at £6 billion. This paper uses multi-sectoral economic models to explore the impact that these (temporary) expenditures could have on the Scottish economy. It is shown that the standard Input-Output (IO) modelling approach significantly overstates the employment and value added impacts compared to Computable General Equilibrium (CGE) methods – in which short-run scarcity of factors of production are explicitly modelled. CGE results (under myopic and forward-looking model specifications) produce smaller impacts during the timespan of expenditures but, unlike IO methods, identify non-trivial "legacy effects" after the expenditures cease.

  • Fadaeenejad, M., Shamsipour, R., Rokni, S.D., and Gomes, C.  New approaches in harnessing wave energy: with special attention to small islands.  Renewable and Sustainable Energy Reviews 29: 345-354, 2014.
    Open Access >>
    Read Abstract >>

    The application of renewable energies has increased rapidly in the previous decade to solve some problems such as growing energy demand and environmental issues. Wave power as a high potential renewable energy, is more predictable compared to other renewable sources. Although there are many research works about wave energy, however a few of them considered a suitable wave energy converter (WEC) as a power system for remote islands. Wave energy potential for remote islands is discussed in this review by regarding environmental impacts, various types of wave energy converters and applied wave power projects for various islands. The results show that wave energy plays a key role for sustainable development of offshore islands by considering the traditional looks and environmental protection.

  • Perveen, R., Kishor, N., and Mohanty, S.R.  Off-shore wind farm development: Present status and challenges.  Renewable and Sustainable Energy Reviews 29: 780-792, 2014.
    Open Access >>
    Read Abstract >>

    Offshore wind farm (OWF) is an emerging technology in the wind energy conversion system. These wind resources are abundant, stronger, and are more consistent in terms of their availability than land-based wind resources. As a matter of fact significantly higher energy production is achieved due to larger wind turbine ratings and stronger wind profiles. This paper highlights the present scenario and challenges in development of offshore wind power. The challenges and opportunities that exist in the development stages of an offshore wind farm project, from exploration to erection and installation of wind turbines, construction of platforms and laying of sea cables, up to maintenance and de-commissioning, involving important technical aspects are addressed. An application of high voltage direct current (HVDC) transmission for integration of large scale offshore wind farm with onshore grid is attractive as compared to high voltage alternating current (HVAC) transmission system. To make the offshore wind farm feasible, reliable and secure, the different aspects in its planning, design and operation are also reviewed in this paper.

  • Jia, Z., Wang, B., Song, S., and Fan, Y.  Blue energy: Current technologies for sustainable power generation from water salinity gradient.  Renewable and Sustainable Energy Reviews 31: 91-100, 2014.
    Read Abstract >>

    "Salinity energy" stored as the salinity difference between seawater and freshwater is a large-scale renewable resource that can be harvested and converted to electricity, but extracting it efficiently as a form of useful energy remains a challenge. With the development of membrane science and technology, membrane-based techniques for energy extraction from water salinity, such as pressure-retarded osmosis and reverse electro-dialysis, have seen tremendous development in recent years. Meanwhile, many other novel methods for harvesting exergy from water mixing processes, such as electrochemical capacitor and nano-fluidic energy harvesting systems, have been proposed. In this work, an overview and state-of-the-art of the current technologies for sustainable power generation from the water salinity gradient are presented. Characteristics of these technologies are analyzed and compared for this particular application. Based on these entropic energy extracting methods, the water salinity, as the "blue energy", will be another source of renewable energy to satisfy the ever-growing energy demand of human society.

  • Joselin Herbert, G.M., Iniyan, S., and Amutha, D.  A review of technical issues on the development of wind farms.  Renewable and Sustainable Energy Reviews 32: 619-641, 2014.
    Read Abstract >>

    Energy is the prime mover of economic growth and is vital to sustain a modern economic and social development. Renewable energy applications have brought about significant changes in the Indian energy scenario. The identification and efficient use of various renewable energy resources are the thrust areas in energy development. Wind energy is one of the most environment friendly, clean and safe energy resources. The wind energy will continue to be the biggest renewable energy sector in any country in terms of both installed capacity and total potential. This paper reviews some important factors and techniques to be considered for wind turbine installations such as the wind energy resource assessment techniques, environmental factors, grid integration factors, control strategies, impact of offshore wind turbines and hybrid energy technologies, hydrogen production techniques, feed-in tariff mechanism, modeling of wind turbine components including generators, performance improvement techniques. The cost and economic feasibility of the wind energy conversion system as well as the control strategies of wind turbine generators have also been discussed.

  • Tang, H.S., Kraatz, S., Qu, K., Chen, G.Q., Aboobaker, N., and Jiang, C.B.  High-resolution survey of tidal energy towards power generation and influence of sea-level-rise: A case study at coast of New Jersey, USA.  Renewable and Sustainable Energy Reviews 32: 960-982, 2014.
    Read Abstract >>

    The first and a crucial step in development of tidal power, which is now attracting more and more attention worldwide, is a reliable survey of temporal and spatial distribution of tidal energy along coastlines. This paper first reviews the advance in assessment of tidal energy, in particular marine hydrokinetic (MHK) energy, and discusses involved challenges and necessary approaches, and then it makes a thorough survey as an illustrative case study on distributions and top sites of MHK energy within the Might-Atlantic-Bight (MAB) with emphasis on the New Jersey (NJ) coastlines. In view of the needs in actual development of tidal power generation and sensitivity of tidal power to flow speed, the former being proportional to the third power of the latter, a high-resolution and detailed modeling is desired. Data with best available accuracy for coastlines, bathymetry, tributaries, etc. are used, meshes as fine as 20 m and less for the whole NJ coast are generated, and the unstructured grid finite volume coastal ocean model (FVCOM) and high performance computing (HPC) facilities are employed. Besides comparison with observation data, a series of numerical tests have been made to ensure reliability of the modeling results. A detailed tidal energy distribution and a list of top sites for tidal power are presented. It is shown that indeed sea-level-rise (SLR) affects the tidal energy distribution significantly. With SLR of 0.5 m and 1 m, tidal energy in NJ coastal waters increases by 21% and 43%, respectively, and the number of the top sites tends to decrease along the barrier islands facing the Atlantic Ocean and increase in the Delaware Bay and the Delaware River. On the basis of these results, further discussions are made on future development for accurate assessment of tidal energy.

  • Li, Y. and Willman, L.  Feasibility analysis of offshore renewables penetrating local energy systems in remote oceanic areas – A case study of emissions from an electricity system with tidal power in Southern Alaska.  Applied Energy 117: 42-53, 2014.
    Read Abstract >>

    In many remote areas, expensive fossil fuels such as diesel are used to meet local electricity demand. However, their environmental impact is significant. Consequently, some of these areas have started to use hybrid systems that combine renewable energy sources and fossil fuel generation, such as wind–diesel systems, although wind is not feasible in some remote locations and fossil fuels remain the only resource in these areas. Fortunately, offshore renewable energy sources are available in many remote areas close to the ocean. In order to understand the feasibility of using offshore renewables in remote oceanic areas, we recently conducted a systematic study by developing an integrated model. This model includes a supply module, demand module, environmental impact module, and integrating module. Using this model, we mainly study the reduction in emissions resulting from offshore renewable energy penetration in local energy systems. In this article, we present this integrated model and an example study of tidal energy in the Southern Alaska community of Elfin Cove, which relies on diesel fuel for all of its electricity requirements. With 56 kW of tidal power penetrating the energy system, we found that almost 12,000 gallons of diesel fuel are displaced per year. This results in an annual emissions reduction of almost 244,000 lb CO2 and about 1400 lb CO, as well as considerable reductions of PM-10, NOx, and SOx. The newly developed integrated model is expected to be used to analyze other aspects of tidal energy (and offshore renewable energy in general) in remote areas. For example, since the electricity demand in some remote areas varies significantly throughout the year, we recommend that tidal power should be used with a storage system.

  • Espinosa, N., Hösel, M., Jørgensen, M., and Krebs, F.C.  Large scale deployment of polymer solar cells on land, on sea and in the air.  Energy and Environmental Science 7(3): 855-866, 2014.
    Read Abstract >>

    With the development of patterns that connect all cells in series, organic photovoltaics have leapt a step forward being ahead of other solar and even other energy technologies in terms of manufacturing speed and energy density. The important questions of how they are meant to be installed for producing power and what the requirements are yet to be explored. We present here the installation of organic solar cell modules in different settings (terrestrial, marine and airborne). For the evaluation of these installations deployed at DTU, we have used the life cycle assessment tools, and calculated key parameters in order to assess their environmental impact. The novel technology when installed in a solar park system can generate more than 1300 kW h kWp-1 of electricity a year, which means that the whole system can pay the energy invested back before the first year of operation, in 320 days. If this electricity is fed back to the same electricity supply system that was used for manufacturing the potential saving of more than 13 GJ of primary energy per kWp per year can be reached. With the real data logged, a dynamic energy payback time has been furthermore calculated for the case of the solar tube installation, giving a value of 1.1 years.

  • Natarajan, A.  An overview of the state of the art technologies for multi-MW scale offshore wind turbines and beyond.  WIREs Energy and Environment 3(2): 111-121, 2014.
    Read Abstract >>

    An overview of technological trends in the design of multi-mega Watt wind turbines focused on the offshore sector is presented. The state of the art technologies for wind turbine design are multidisciplinary ranging from blade aeroelasticity, power transmission to the generator, to advanced control systems that ensure performance and the design of offshore support structures to minimize cost of energy. Light weight carbon fiber blades, aeroelastic tailoring using bend–twist coupling are discussed in coordination with a multitude of aerodynamic technologies for optimal power capture such as high-lift airfoils, flaps, and flat-back airfoil designs. The pitch control of the turbine responsible for rotating the blades about its axis to reduce loads is the primary load reducing mechanism of the wind turbine, for which technologies that enable wind sensing such as forward looking LIDARs and redundancy mechanisms such as individual blade pitch control offer promising advances. The lack of reliability of the gearbox has resulted in drive train technologies to move toward direct drives, whose benefits and liabilities are assessed in combination with generator concepts. The support structures are discussed within an offshore framework for shallow, moderately deep, and deep waters. Fixed substructures such as monopiles, tripods, jackets, as well as floaters such as spar buoys and tension leg platforms are brought forth. The advances in these different component technologies that enable the wind turbine system to be reliable and cost effective are described as a precursor to further in-depth reviews.

  • Appiott, J., Dhanju, A., and Cicin-Sain, B.  Encouraging renewable energy in the offshore environment.  Ocean and Coastal Management 90: 58-64, 2014.
    Read Abstract >>

    Traditionally, offshore energy exploitation has occurred through production of fossil fuels. However, increasing attention is being focused on various forms of offshore renewable energy as it can reduce fossil fuel emissions, create green jobs, lead to local economic returns for coastal communities, and facilitate movement towards a low-carbon economy. Recent research indicates the presence of significant offshore energy in the form of winds, waves, currents, and tides. Spurred by the promising potential of these resources and an improving policy environment, efforts are under way in different offshore areas to assess resource potential, examine various technical approaches, and install renewable energy devices. Obstacles to development of this industry remain, and include technical difficulties, potential environmental impacts, and lack of funding. These obstacles must be overcome before the industry can become a viable alternative to carbon-based energy sources. Policy alternatives to overcome these obstacles, to stimulate offshore renewable energy development, and to level the playing field for these resources are discussed.

  • Goundar, J.N. and Ahmed, M.R.  Marine current energy resource assessment and design of a marine current turbine for Fiji.  Renewable Energy 65: 14-22, 2014.
    Read Abstract >>

    Pacific Island Countries (PICs) have a huge potential for renewable energy to cater for their energy needs. Marine current energy is a reliable and clean energy source. Many marine current streams are available in Fiji's waters and large amount of marine current energy can be extracted using turbines. Horizontal axis marine current turbine (HAMCT) can be used to extract marine current energy to electrical energy for commercial use. For designing a HAMCT, marine current resource assessment needs to done. A potential site was identified and resource assessment was done for 3 months. The coordinates for the location are 18°12'1.78S and 177°38'58.21E; this location is called Gun-barrel passage. The average depth is 17.5 m and the width is nearly 20 m -- the distance from land to the location is about 500 m. A multi cell aquadopp current profiler (ADCP) was deployed at the site to record marine currents. Strong marine currents are recorded at this location, as a combination of both tidal and rip currents. The maximum current velocity exceeds 2.5 m/s, for days with large waves. The average velocity was 0.85 m/s and power density for the site was 525 W/m2. This site has good potential for marine current and HAMCT can be installed to extract power. A turbine with diameter between 5 and 8 m would be suitable for this site. Therefore, a 5 m HAMCT is designed for this location. The HF10XX hydrofoils were used from blade root (r/R = 0.2) to tip (r/R = 1.0). HF10XX series hydrofoil sections were designed to operate at varying turbine operating conditions; these hydrofoils have good hydrodynamic characteristics at the operating Reynolds number. The turbine is designed to operate at rated marine current speed of 1.5 m/s, cut in speed of 0.5 m/s and cut off speed of 3 m/s at a tip speed ratio (TSR) of 4.2.

Public Opinion

  • Heras-Saizarbitoria, I., Zamanillo, I., and Laskurain, I.  Social acceptance of ocean wave energy: A case study of an OWC shoreline plant.  Renewable and Sustainable Energy Reviews 27: 515-524, 2013.  
    Read Abstract >>

    Social acceptance, along with technical, economic and legal aspects, is a prerequisite for the successful adoption of renewable energies. Research into the social acceptance of the underlying implementation of different renewable energy technologies, such as grid connected photovoltaic solar, biomass and wind power plants, is increasingly gaining interest. Nevertheless, studies that address the issue of the social acceptance of sea wave energy plants are very rare. This article aims at making a contribution towards filling this gap analyzing the community acceptance of the oscillating water column (OWC) shoreline plant of Mutriku, a facility that has been subject of great interest due to its innovative technical characteristics. This article's findings emphasize the importance of effective and meaningful social involvement in the successful promotion and diffusion of renewable energy infrastructures such as wave energy plants.

  • Lilley, J. and Firestone, J.  The effect of the 2010 Gulf oil spill on public attitudes toward offshore oil drilling and wind development.  Energy Policy 62: 90-98, 2013.
    Read Abstract >>

    In April 2010, the Deepwater Horizon oil well exploded, releasing over four million barrels of oil into the Gulf of Mexico. This paper presents data from two national mail surveys undertaken in 2008 and 2010 that compare public attitudes to both offshore oil drilling and offshore wind development pre- and post-spill. The results show that while there was a drop in support for expanded drilling (from 66% in 2008 to 59% in 2010) the change was not significant. There was, however, a significant decrease in support for offshore drilling among coastal residents. There was a slight, non-significant increase in support for offshore wind development which remained significantly higher than support for offshore oil (80% in 2008 and 82% in 2010). Despite there being no significant change in overall support levels, there was a shift in the strength of feeling regarding offshore oil, with 80% of Americans either less supportive or more opposed to expanded drilling in 2010 than they were in 2008.

  • Westerberg, V., Jacobsen, J.B., and Lifran, R.  The case for offshore wind farms, artificial reefs and sustainable tourism in the French Mediterranean.  Tourism Management 34: 172-183, 2013.  
    Read Abstract >>

    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.

Policy and Legal Issues

  • Dubbs, L., Keeler, A.G., and O'Meara, T.  Permitting, risk and marine hydrokinetic energy development.  Electricity Journal 26(10): 64-74, 2013.  
    Read Abstract >>

    The existing permitting process places significant burdens on MHK testing and prototyping that are significant impediments to technological progress. These permitting processes do not adequately consider the reduced risk from the very small physical scale of current projects, and are also influenced by the sheer uncertainty associated with novel technologies. A more nuanced application of the precautionary principle in applying biodiversity protection statutes to permitting MHK devices is warranted.

Life Cycle Assessment

  • Arvesen, A., Birkeland, C., and Hertwich, E.G.  The importance of ships and spare parts in LCAs of offshore wind power.  Environmental Science & Technology 47(6): 2948-2956, 2013.  
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    We develop and assess life cycle inventories of a conceptual offshore wind farm using a hybrid life cycle assessment (LCA) methodology. Special emphasis is placed on aspects of installation, operation, and maintenance, as these stages have been given only cursory consideration in previous LCAs. The results indicate that previous studies have underestimated the impacts caused by offshore operations and (though less important) exchange of parts. Offshore installation and maintenance activities cause 28% (10 g CO2-Eq/kWh) of total greenhouse gas emissions and 31–45% of total impact indicator values at the most (marine eutrophication, acidification, particulates, photochemical ozone). Transport and dumping of rock in installation phase and maintenance of wind turbines in use phase are major contributory activities. Manufacturing of spare parts is responsible for 6% (2 g CO2-Eq/kWh) of greenhouse gas emissions and up to 13% of total impact indicator values (freshwater ecotoxicity). Assumptions on lifetimes, work times for offshore activities and implementation of NOx abatement on vessels are shown to have a significant influence on results. Another source of uncertainty is assumed operating mode data for vessels determining fuel consumption rates.

  • Raadal, H.L., Vold, B.I., Myhr, A., and Nygaard, T.A.  GHG emissions and energy performance of offshore wind power.  Renewable Energy 66: 314-324, 2014.
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    This paper presents specific life cycle GHG emissions from wind power generation from six different 5 MW offshore wind turbine conceptual designs. In addition, the energy performance, expressed by the energy indicators Energy Payback Ratio (EPR) Energy Payback Time (EPT), is calculated for each of the concepts. There are currently few LCA studies in existence which analyse offshore wind turbines with rated power as great as 5 MW. The results, therefore, give valuable additional environmental information concerning large offshore wind power. The resulting GHG emissions vary between 18 and 31.4 g CO2-equivalents per kWh while the energy performance, assessed as EPR and EPT, varies between 7.5 and 12.9, and 1.6 and 2.7 years, respectively. The relatively large ranges in GHG emissions and energy performance are chiefly the result of the differing steel masses required for the analysed platforms. One major conclusion from this study is that specific platform/foundation steel masses are important for the overall GHG emissions relating to offshore wind power. Other parameters of importance when comparing the environmental performance of offshore wind concepts are the lifetime of the turbines, wind conditions, distance to shore, and installation and decommissioning activities. Even though the GHG emissions from wind power vary to a relatively large degree, wind power can fully compete with other low GHG emission electricity technologies, such as nuclear, photovoltaic and hydro power.

Wildlife and Habitat Impacts

  • Teilmann, J. and Carstensen, J.  Negative long term effects on harbour porpoises from a large scale offshore wind farm in the Baltic – evidence of slow recovery.  Environmental Research Letters 7(4): art. 045101, 2012.
    Open Access >>   
    Read Abstract >>

    Offshore wind farms constitute a new and fast growing industry all over the world. This study investigates the long term impact on harbour porpoises, Phocoena phocoena, for more than 10 years (2001–12) from the first large scale offshore wind farm in the world, Nysted Offshore Wind Farm, in the Danish western Baltic Sea (72 x 2.3 MW turbines). The wind farm was brought into full operation in December 2003. At six stations, acoustic porpoise detectors (T–PODs) were placed inside the wind farm area and at a reference area 10 km to the east, to monitor porpoise echolocation activity as a proxy of porpoise presence. A modified statistical BACI design was applied to detect changes in porpoise presence before, during and after construction of the wind farm. The results show that the echolocation activity has significantly declined inside Nysted Offshore Wind Farm since the baseline in 2001–2 and has not fully recovered yet. The echolocation activity inside the wind farm has been gradually increasing (from 11% to 29% of the baseline level) since the construction of the wind farm, possibly due to habituation of the porpoises to the wind farm or enrichment of the environment due to reduced fishing and to artificial reef effects.

  • Dähne, M. et al.  Effects of pile-driving on harbour porpoises (Phocoena phocoena) at the first offshore wind farm in Germany.  Environmental Research Letters 8(2): art. 025002, 2013.
    Open Access >>
    Read Abstract >>

    The first offshore wind farm 'alpha ventus' in the German North Sea was constructed north east of Borkum Reef Ground approximately 45 km north off the German coast in 2008 and 2009 using percussive piling for the foundations of 12 wind turbines. Visual monitoring of harbour porpoises was conducted prior to as well as during construction and operation by means of 15 aerial line transect distance sampling surveys, from 2008 to 2010. Static acoustic monitoring (SAM) with echolocation click loggers at 12 positions was performed additionally from 2008 to 2011. SAM devices were deployed between 1 and 50 km from the centre of the wind farm. During aerial surveys, 18 600 km of transect lines were covered in two survey areas (10 934 and 11 824 km²) and 1392 harbour porpoise sightings were recorded. Lowest densities were documented during the construction period in 2009. The spatial distribution pattern recorded on two aerial surveys three weeks before and exactly during pile-driving points towards a strong avoidance response within 20 km distance of the noise source. Generalized additive modelling of SAM data showed a negative impact of pile-driving on relative porpoise detection rates at eight positions at distances less than 10.8 km. Increased detection rates were found at two positions at 25 and 50 km distance suggesting that porpoises were displaced towards these positions. A pile-driving related behavioural reaction could thus be detected using SAM at a much larger distance than a pure avoidance radius would suggest. The first waiting time (interval between porpoise detections of at least 10 min), after piling started, increased with longer piling durations. A gradient in avoidance, a gradual fading of the avoidance reaction with increasing distance from the piling site, is hence most probably a product of an incomplete displacement during shorter piling events.

  • Bergström, L., Kautsky, L., Malm, T., Rosenberg, R., Wahlberg, M., Åstrand Capetillo, N., and Wilhelmsson, D.  Effects of offshore wind farms on marine wildlife – a generalized impact assessment.  Environmental Research Letters 9(3): art. 034012, 2014.
    Open Access >>   
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    Marine management plans over the world express high expectations to the development of offshore wind energy. This would obviously contribute to renewable energy production, but potential conflicts with other usages of the marine landscape, as well as conservation interests, are evident. The present study synthesizes the current state of understanding on the effects of offshore wind farms on marine wildlife, in order to identify general versus local conclusions in published studies. The results were translated into a generalized impact assessment for coastal waters in Sweden, which covers a range of salinity conditions from marine to nearly fresh waters. Hence, the conclusions are potentially applicable to marine planning situations in various aquatic ecosystems. The assessment considered impact with respect to temporal and spatial extent of the pressure, effect within each ecosystem component, and level of certainty. Research on the environmental effects of offshore wind farms has gone through a rapid maturation and learning process, with the bulk of knowledge being developed within the past ten years. The studies showed a high level of consensus with respect to the construction phase, indicating that potential impacts on marine life should be carefully considered in marine spatial planning. Potential impacts during the operational phase were more locally variable, and could be either negative or positive depending on biological conditions as well as prevailing management goals. There was paucity in studies on cumulative impacts and long-term effects on the food web, as well as on combined effects with other human activities, such as the fisheries. These aspects remain key open issues for a sustainable marine spatial planning.

  • Mateos-Rodríguez, M., Muñoz, A.-R., and Arroyo, G.M.  Assessment of offshore wind farm effects on birds and needs to plan their future development in Spain.  Ardeola 59(2): 217-236, 2012.
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    Wind farms have a negative impact on several animal populations, with birds and bats assumed to be among the most heavily affected taxa. In addition to the extensive development of wind power on land, currently several European countries have offshore wind farms (OWFs) in operation, as well as proposals to build many more. Considering that seabirds spend more than 90% of their life at sea, it is clear that they may interact with these man-made structures. To date, information on how to measure the impact of OWFs on seabirds is very scarce. In many cases it comes from non-peer reviewed reports made for specific assessment studies, very often carried out without appropriate standard methodologies, that raise questions regarding the level of confidence that they merit. In this paper, we describe the current political framework concerning the possible development of OWFs in Spain. Based on this, we comment on both the relevant variables necessary to assess the impacts of OWFs on birds and the methodologies available to collect those variables in the field, discussing the strengths and weaknesses of each method. We show the importance of collision risk models, vulnerability indexes, cumulative impact assessment and population viability analysis as management tools. Mitigation measures that have the potential to minimise impacts are also summarised. We conclude with a discussion of the different steps to follow to attain a 'clean' development of offshore wind energy in Spain.

  • Thompson, P.M., Hastie, G.D., Nedwell, J., Barham, R., Brookes, K.L., Cordes, L.S., Bailey, H., and McLean, N.  Framework for assessing impacts of pile-driving noise from offshore wind farm construction on a harbour seal population.  Environmental Impact Assessment Review 43: 73-85, 2013.
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    Offshore wind farm developments may impact protected marine mammal populations, requiring appropriate assessment under the EU Habitats Directive. We describe a framework developed to assess population level impacts of disturbance from piling noise on a protected harbour seal population in the vicinity of proposed wind farm developments in NE Scotland. Spatial patterns of seal distribution and received noise levels are integrated with available data on the potential impacts of noise to predict how many individuals are displaced or experience auditory injury. Expert judgement is used to link these impacts to changes in vital rates and applied to population models that compare population changes under baseline and construction scenarios over a 25 year period. We use published data and hypothetical piling scenarios to illustrate how the assessment framework has been used to support environmental assessments, explore the sensitivity of the framework to key assumptions, and discuss its potential application to other populations of marine mammals.

  • Miller, R.G., Hutchison, Z.L., Macleod, A.K., Burrows, M.T., Cook, E.J., Last, K.S., and Wilson, B.  Marine renewable energy development: assessing the Benthic Footprint at multiple scales.  Frontiers in Ecology and the Environment 11(8): 433-440, 2013.
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    Increasing concerns over global climate change and sustainable fuel procurement are driving the search for new ways to derive energy from the seas. Globally, the offshore wind energy sector has progressed rapidly, and wave and tidal-current energy converters are now approaching deployment at commercial scales. To date, most studies of the ecological effects of marine renewable energy development have concentrated on birds and marine mammals. Here, we focus on the consequences for benthic flora and fauna, and for benthic habitats across a variety of scales. We use a "Benthic Footprint" concept to discuss the potential for species-specific environmental responses, and to consider the poorly understood cumulative effects of wind, wave, and tidal-current energy operations on marine ecosystems. Collaborations between ecologists, industry specialists, and government bodies, as well as better designs for devices, arrays, and developments consisting of multiple arrays, can contribute to the goal of reducing the Benthic Footprint of marine renewable energy, thereby facilitating large-scale implementation of these technologies.

  • Masden, E.A., Foster, S., and Jackson, A.C.  Diving behaviour of Black Guillemots Cepphus grylle in the Pentland Firth, UK: potential for interactions with tidal stream energy developments.  Bird Study 60(4): 547-549, 2013.
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    Black Guillemots Cepphus grylle were recorded diving in the Pentland Firth to an average depth of 32 metres and an overall maximal depth of 43 metres. The majority (88%) of dives were benthic with a median dive duration of 95 seconds, and a maximal dive duration of 131 seconds. The results provide empirical evidence that Black Guillemots use depths within the water column at which tidal turbines are likely to operate. Although limited, our data suggest the potential for interactions between Black Guillemots and marine renewable energy devices.

  • Krone, R., Gutow, L., Joschko, T.J., and Schröder, A.  Epifauna dynamics at an offshore foundation – Implications of future wind power farming in the North Sea.  Marine Environmental Research 85: 1-12, 2013.
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    In the light of the introduction of thousands of large offshore wind power foundations into the North Sea within the next decades, this manuscript focuses on the biofouling processes and likely reef effects. The study explores the macrozoobenthos (biofouling) colonization at an offshore platform which is comparable to offshore wind turbine foundations. A total of 183 single samples were taken and the parameters water depth and time were considered comparing biofouling masses and communities. The blue mussel Mytilus edulis, Anthozoa and the Amphipoda Jassa spp. were the dominant species. The community from the 1 m zone and those from the 5 and 20–28 m zones can clearly be differentiated. The 10 m zone community represents the transition between the M.edulis dominated 1 m and 5 m zones and the Anthozoa dominated 20–28 m zone. In the future offshore wind farms, thousands of wind turbine foundations will provide habitat for a hard bottom fauna which is otherwise restricted to the sparse rocky habitats scattered within extensive sedimentary soft bottoms of the German Bight. However, offshore wind power foundations cannot be considered natural rock equivalents as they selectively increase certain natural hard bottom species. The surface of the construction (1280 m²) was covered by an average of 4300 kg biomass. This foundation concentrates on its footprint area (1024 m²) 35 times more macrozoobenthos biomass than the same area of soft bottom in the German exclusive economic zone (0.12 kg m-2), functioning as a biomass hotspot. Concerning the temporal biomass variation, we assume that at least 2700 kg biomass was exported on a yearly basis. 345 × 104 single mussel shells of different sizes were produced during the study period. It is anticipated that the M.edulis  abundance will increase in the North Sea due to the expansion of the offshore wind farm development. This will result in the enhanced production of secondary hard substrate (mussel shells) and its associated fauna and will intensify filtration rates of the seawater. This predicted ecological system change is coined the 'Mytilusation' of the German Bight.

  • Hooper, T. and Austen, M.  Tidal barrages in the UK: Ecological and social impacts, potential mitigation, and tools to support barrage planning.  Renewable and Sustainable Energy Reviews 23: 289-298, 2013.
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    The UK Government is committed to ambitious targets to reduce carbon emissions. The large tidal ranges in estuaries on the west coast of the UK make the deployment of tidal barrages an attractive proposition, and repeated feasibility studies have been undertaken. No barrage scheme has yet been taken forward, and one factor contributing to this reluctance to proceed is the significant environmental impacts that could result from the barrage construction and operation. This paper provides a detailed review of the current understanding of the potential ecological and social impacts of tidal barrages, including a case study of La Rance in northern France, and a discussion of strategies for mitigating barrage impacts. The review considers how more comprehensive ecological modelling could reduce uncertainty in predicting the impacts in specific estuaries, and discusses the use of Multi-criteria Analysis and ecosystem valuation as tools for evaluating the disparate costs and benefits of barrages schemes.

  • Lovich, J.E. and Ennen, J.R.  Assessing the state of knowledge of utility-scale wind energy development and operation on non-volant terrestrial and marine wildlife.  Applied Energy 103: 52-60, 2013.
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    A great deal has been published in the scientific literature regarding the effects of wind energy development and operation on volant (flying) wildlife including birds and bats, although knowledge of how to mitigate negative impacts is still imperfect. We reviewed the peer-reviewed scientific literature for information on the known and potential effects of utility-scale wind energy development and operation (USWEDO) on terrestrial and marine non-volant wildlife and found that very little has been published on the topic. Following a similar review for solar energy we identified known and potential effects due to construction and eventual decommissioning of wind energy facilities. Many of the effects are similar and include direct mortality, environmental impacts of destruction and modification of habitat including impacts of roads, and offsite impacts related to construction material acquisition, processing and transportation. Known and potential effects due to operation and maintenance of facilities include habitat fragmentation and barriers to gene flow, as well as effects due to noise, vibration and shadow flicker, electromagnetic field generation, macro- and micro-climate change, predator attraction, and increased fire risk. The scarcity of before-after-control-impact studies hinders the ability to rigorously quantify the effects of USWEDO on non-volant wildlife. We conclude that more empirical data are currently needed to fully assess the impact of USWEDO on non-volant wildlife.

  • Busch, D.S., Greene, C.M., and Good, T.P.  Estimating effects of tidal power projects and climate change on threatened and endangered marine species and their food web.  Conservation Biology 27(6): 1190-1200, 2013.
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    Marine hydrokinetic power projects will operate as marine environments change in response to increased atmospheric carbon dioxide concentrations. We considered how tidal power development and stressors resulting from climate change may affect Puget Sound species listed under the U.S. Endangered Species Act (ESA) and their food web. We used risk tables to assess the singular and combined effects of tidal power development and climate change. Tidal power development and climate change posed risks to ESA-listed species, and risk increased with incorporation of the effects of these stressors on predators and prey of ESA-listed species. In contrast, results of a model of strikes on ESA-listed species from turbine blades suggested that few ESA-listed species are likely to be killed by a commercial-scale tidal turbine array. We applied scenarios to a food web model of Puget Sound to explore the effects of tidal power and climate change on ESA-listed species using more quantitative analytical techniques. To simulate development of tidal power, we applied results of the blade strike model. To simulate environmental changes over the next 50 years, we applied scenarios of change in primary production, plankton community structure, dissolved oxygen, ocean acidification, and freshwater flooding events. No effects of tidal power development on ESA-listed species were detected from the food web model output, but the effects of climate change on them and other members of the food web were large. Our analyses exemplify how natural resource managers might assess environmental effects of marine technologies in ways that explicitly incorporate climate change and consider multiple ESA-listed species in the context of their ecological community.

  • Winiarski, K.J., Miller, D.L., Paton, P.W.C., and McWilliams, S.R.  A spatial conservation prioritization approach for protecting marine birds given proposed offshore wind energy development.  Biological Conservation 169: 79-88, 2014.
    Open Access >>
    Read Abstract >>

    There are currently no offshore wind energy developments (OWEDs) in North America, although numerous OWEDs have been proposed along the Atlantic Coast. Development pressure has been a catalyst for marine spatial planning (MSP) to identify suitable areas for OWED. However, integrating complex ecological information to guide OWED siting remains a substantial challenge. We developed spatial distribution models of marine birds from aerial surveys that we conducted from 2010 to 2012 throughout a 3800km² area off the coast of Rhode Island. For seven groups of marine birds, we constructed either a density surface model or a presence-absence model that incorporated relevant environmental covariates. We integrated our spatial models, along with uncertainty, using spatial conservation prioritization (SCP) software. This identified sites with high marine bird conservation priority that aided evaluation of proposed OWED sites. We found that shallow nearshore waters had the highest conservation priority overall, but we also detected key offshore areas of high priority. Hypothetical OWEDs placed in conservation priority areas significantly reduced the overall distribution of focal species. Currently proposed OWED sites are located in areas of relatively low conservation priority and so would not substantially reduce the overall distribution of marine birds. This SCP approach when combined with quantitative models of bird distribution given relevant environmental covariates provides a robust framework that satisfies the principles of ecosystem-based MSP. Thus, this combined SCP-distribution modeling framework should be extremely helpful to decision makers as they evaluate proposed siting locations of OWEDs in the context of a dynamic marine system.

  • Abanades, J., Greaves, D., and Iglesias, G.  Wave farm impact on the beach profile: A case study.  Coastal Engineering 86: 36-44, 2014.
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    If wave energy is to become a fully-fledged renewable, its environmental impacts must be fully understood. The objective of the present work is to examine the impact of a wave farm on the beach profile through a case study. The methodology is based on two coupled numerical models: a nearshore wave propagation model and a morphodynamic model, which are run in two scenarios, both with and without the wave farm. Wave data from a nearby coastal buoy are used to prescribe the boundary conditions. A positive effect on the wave climate, the cross-shore sediment transport and, consequently, the evolution of the beach profile itself due to the presence of the wave farm was found. The wave farm leads to a reduction in the erosion of the beach face. This work constitutes the first stage of the investigation of the effectiveness of a wave farm as a coastal defence measure, and the accuracy of the quantification of the erosion reduction will be enhanced in future research. In any case, the overarching picture that emerges is that wave farms, in addition to providing carbon-free energy, can be used as elements of a coastal defence scheme.

  • Hammar, L., Wikstrøm, A., and Molander, S.  Assessing ecological risks of offshore wind power on Kattegat cod.  Renewable Energy 66: 414-424, 2014.
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    Offshore wind power is expanding with particular development plans in the Baltic and the North Sea. To reassure an environmentally acceptable development, regulatory authorities need to make informed decisions even when evidence and experience are scarce. In this study Ecological Risk Assessment (ERA) has been applied on a wind farm project in Kattegat, proposed within a spawning ground for the Kattegat cod, a threatened population of Atlantic cod (Gadus morhua L.). Six stressors with potential impacts on cod and related to wind farms were investigated. Three of them – extreme noise from pile driving, noise from vessels, and disturbances due to cable-trenching – are related to the construction phase, while lubricant spills and noise from turbines together with electric fields from cables are related to the operation phase. The ecological risk was derived from the combined likelihood and magnitude of potential adverse effects from stressors to the cod population using a weight-of-evidence (WOE) ranking procedure. Available evidence was evaluated based on its reliability, and contradictory arguments were balanced against each other using evidence maps. The option of performing hazardous construction events (e.g. pile-driving) outside biologically sensitive periods was incorporated in the assessment. It was shown that the construction of the wind farm poses a high risk to cod, as defined by the ranked and combined likelihoods and magnitudes of adverse effects. However by avoiding particular construction events during the cod recruitment period ecological risks can be significantly reduced. Specifically for this case, ecological risks are reduced from high to low by avoiding pile-driving from December through June, which confirms previous indications that pile-driving is the most ecologically hazardous activity of offshore wind power development. Additional risk reduction is achieved by avoiding cable trenching from January through May. The study thus illustrates the effectiveness of time-planning for risk reduction. Importantly, the study illustrates how combined ERA and WOE methods can be valuable for handling uncertainties of environmental impacts within offshore industrial development.

  • Adams, T.P., Miller, R.G., Aleynik, D., and Burrows, M.T.  Offshore marine renewable energy devices as stepping stones across biogeographical boundaries.  Journal of Applied Ecology 51(2): 330-338, 2014.
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    1. Offshore renewable energy provides an increasing component of our electricity supply. We have limited understanding of the potential environmental impacts of these developments, particularly in the move to larger scales. Surfaces provided by devices offer novel habitat to marine organisms, which may allow species to spread to new areas. 2. We used coupled biological and hydrodynamic models to investigate the spread of intertidal marine organisms with pelagic larvae (such as barnacles or gastropods) in the region around south-western Scotland. We assessed the impact of novel habitat on dispersal and its role in allowing transgression of physical barriers. 3. Model renewable energy device sites provided habitat for pelagic larval particles that would otherwise have been lost offshore. They also provided a source of larvae for existing coastal sites. 4. Many offshore devices fulfilled source and destination (or intermediate connection) roles, creating new dispersal pathways, and allowing previously impossible northward dispersal from the Northern Irish coast to Scotland. 5. Synthesis and applications. New habitat close to biogeographical barriers has implications for existing species' distributions and genetic population structure. It also affects the spread of non-native species and 'climate migrants'. Monitoring these sites for the presence of such species will be important in determining the future ecology of coastal habitat and in maintaining economic aquaculture and marina operations. Future model studies should focus on particular species of importance, taking account of their biology and current distribution.

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