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This article aims to analyse the economic viability of floating wave energy farms for the present and the next twenty years. The energy potential of the waves mainly depends on the climate, so the current and near future analysis is crucial to determine the economic viability of wave energy farms in a particular location. Current and near future wave resources were considered to assess the main parameters (Net Present Value (NPV), Internal Rate of Return (IRR) and Levelized Cost of Energy (LCOE)) that allow to know the economic feasibility of wave energy farms. This study takes one step forward in determining the economic evaluation of wave energy farms located in deep waters using their future energy projections. The case of study in this paper is the Atlantic coast of the Iberian Peninsula. Results indicate that the future wave energy reduction principally affects the NPV and LCOE of the wave farm. [ABSTRACT FROM AUTHOR]

This article aims to analyse the economic viability of floating wave energy farms for the present and the next twenty years. The energy potential of the waves mainly depends on the climate, so the current and near future analysis is crucial to determine the economic viability of wave energy farms in a particular location. Current and near future wave resources were considered to assess the main parameters (Net Present Value (NPV), Internal Rate of Return (IRR) and Levelized Cost of Energy (LCOE)) that allow to know the economic feasibility of wave energy farms. This study takes one step forward in determining the economic evaluation of wave energy farms located in deep waters using their future energy projections. The case of study in this paper is the Atlantic coast of the Iberian Peninsula. Results indicate that the future wave energy reduction principally affects the NPV and LCOE of the wave farm. [ABSTRACT FROM AUTHOR]

The aim of the present paper is to propose a new methodology for the production and installation of green artificial reefs (GARs) in shallow waters, with special attention to the transport stages. The process includes both onshore (manufacturing, road transport and unload at port) and offshore (load at port, sea transport, positioning, and deployment tasks) stages. Two different types of truck were analysed for the road transport. Furthermore, three different options were considered for sea transport: a workboat powered by liquefied natural gas, a barge using diesel (0.1% sulphur) as fuel, and an electric specific design barge. A simulation tool called AGARDO (Automatic Green Artificial Reef Deploy Optimisation) was developed for such a purpose. An estuary located in Galicia (North-West of Spain), where 180 GAR units must be installed, has been considered as case study. AGARDO was used to obtain results concerning process total time, equivalent CO2 emissions and costs for different scenarios. Consequently, the use of the proposed methodology allows the decision-maker to select the best option in terms of costs, emissions and time. AGARDO can be easily adapted to other case studies, with different onshore and offshore options. [ABSTRACT FROM AUTHOR]

Abstract The present paper presents the methodology and development of a planning tool for the installation of marine renewable energy systems, which enables the identification of suitable areas for this purpose. The marine spatial planning is one of the challenges of the offshore renewable energies. This is one of the reasons to write this paper, because there are areas where the energy potential is great but with real limitations for installing an offshore renewable energy farm. This methodology is based on the development of automated and interactive GIS tools in order to enable the user to change inputs according to his research objectives. The developed tools are applied to a case study referring to the Portuguese coast and the obtained results enable the identification of several areas, suitable for the development of marine renewable energies projects. The methodology and the developed tools intend to be a contribution for the Maritime Spatial Planning of the Portuguese coast and can be applied to other countries as well whenever the necessary information is available. Highlights • Methodology and development of a planning tool for marine renewable energy. • Identification of suitable areas of installing. • GIS tools to change inputs according to his objectives. • Maritime Spatial Planning of the Portuguese coast. • Results identify suitable areas for marine renewable energies. [ABSTRACT FROM AUTHOR]

This paper develops a methodology to determine the installation costs of a floating wind farm installed offshore, the value of which depends on the type of floating offshore wind platform installed. In this context, several costs in the installation process have been defined: installation of the offshore wind generators, installation of the floating offshore wind substructures, installation of the anchoring and mooring, installation of the electric systems and the commissioning or start up of the floating offshore wind farm. Furthermore, several installation scenarios have been taken into consideration regarding the shipyard surface and draught, the number of lifts, the transport, the mooring strategy and the substation configuration. The method, tested for the region of Galicia and for three sorts of floating substructures: spar, semisubmersible and tensioned leg, allows to compare different alternatives of installing a floating offshore and the most important aspects of the costs proposed. It can be useful for investors who decide to use this type of offshore renewable energy in the future. [ABSTRACT FROM AUTHOR]

The present paper compares in economic terms, four technological alternatives to use offshore renewable energies: floating offshore wind energy technology, floating offshore wave energy systems, floating offshore co-located systems and floating offshore hybrid systems. These alternatives are compared considering different locations and sizes of the farms. Studies such as this can be useful for planning strategies and decision-making, particularly to investors that have to decide if and how to develop and deploy particular technologies in deep waters. The results indicate that the best alternative considering the life-cycle cost and LCOE is the floating offshore wind energy technology. Floating offshore co-located systems have the second best result, being a better alternative than floating offshore wave energy devices or floating offshore hybrid systems. [ABSTRACT FROM AUTHOR]

The aim of this paper is to determine the main costs and the feasibility of repowering wind farms. For this purpose, two study methods, which depend on legal and wind turbines issues, have been considered. They will provide nine alternatives, whose study will be developed. The methodology has been applied to the particular case of Galicia (North-West of Spain), where there is a good onshore wind resource. Calculations indicate the costs, the Net Present Value (NPV), the Internal Rate of Return (IRR), and the Pay-Back Period of these alternatives. In addition, a sensitivity study has analyzed the main variables of dependence in repowering wind farms. Results show that repowering can be a new alternative for onshore wind farms in areas where old wind turbines are currently installed. [ABSTRACT FROM AUTHOR]

Despite the fact that offshore wind energy will tend towards the floating technologies their economic impact has not been practically evaluated yet. In this context, the aim of this article is to characterize the possible economic alternatives which can be considered in the life-cycle of floating offshore wind farms based on their life-cycle costs. Several groups of variables have been considered for determining these alternatives: wind turbines, floating platforms, mooring system, anchoring process, kind of seabed, electric system, installation, shipyard and maintenance. The method proposed has been applied to the case of the North-West coast of Spain (Galicia region). For this case test three different platforms have been analyzed: Tensioned Leg, Spar and Semisubmersible platforms. Results, which are presented by using maps of the area, conclude that offshore substation, string electric configuration and “tree fall” decommissioning method are the best options for minimizing the costs. In addition, the installation method will be conditioned by the type of floating platform and mooring material, whereas the disposition and anchor decisions are dependent on the geographic location. Results show how the methodology proposed is useful to characterize economically the life-cycle of a floating offshore wind farm. [ABSTRACT FROM AUTHOR]

A methodology is presented to assess the life-cycle costs of combined or hybrid floating offshore renewable energy systems, which is also applicable to general floating offshore renewable energy devices. It accounts explicitly for their life-cycle stages: concept definition, design and development, manufacturing, installation, exploitation and dismantling. It is a tool for decision-making and strategic planning, enabling a better understanding of the technological solutions and the aspects that might accelerate or decelerate the development of the industry. The method presented can be useful for comparing different types of floating offshore hybrid renewable energy technologies in terms of costs. The general methodology has been applied for the particular case of two specific hybrid systems: the W2Power and the Poseidon. Results for two locations in Portugal (São Pedro de Moel and Aguçadoura) indicate that the exploitation, manufacturing and the installation costs are the most important ones, with the exploitation cost being the most important for the W2Power and the manufacturing cost being the most important for the Poseidon. The Levelized Cost Of Energy is lower in São Pedro de Moel but when considering the technology the W2Power has lower Levelized Cost Of Energy in the single unit scenarios and the Poseidon in the farm scenarios. [ABSTRACT FROM AUTHOR]

The aim of this paper is to develop a methodology to determine the economic feasibility of a floating offshore wind farm. The methodology proposed considers that the life-cycle cost of a floating offshore wind farm is composed of the costs of each of the phases of its life-cycle (concept and definition, design and development, manufacturing, installation, exploitation and dismantling). Moreover, they are subdivided considering their sub-costs and taking into account the five components of a floating offshore wind farm: offshore wind turbine, floating platform, mooring, anchoring and electric system. The method ends when the economic feasibility indexes are calculated. The methodology has been used to analyse an offshore location: the Galician region (North-West of Spain). Results indicate that the best economic area in the Galician region is the area located from the Ría de Pontevedra to the Ría de Ribadeo. In addition, comparing the three floating offshore wind platforms, the semisubmersible platform and the spar platform are the best options in economic terms. The method proposed can be used to determine the economic keys in order to develop a floating offshore wind farm in any location. [ABSTRACT FROM AUTHOR]

This paper aims to determine the influence that location has in the life-cycle of a floating offshore wind farm. For this purpose several steps have been considered: determination of the location variables, formulation of the costs whose value depends on these location variables, development of the location economic indexes based on the Levelized Cost of Energy and the Cost of Power, and introduction of the restricted areas where farms cannot be installed. This method will be applied to the particular case of a floating offshore wind farm with semisubmersible platforms and located in the Galician area (North-West of Spain). Results indicate the best location areas where a floating offshore wind farm can be installed in the region selected. This methodology will be useful to determine the importance of the location settings in terms of a floating offshore wind farm. [ABSTRACT FROM AUTHOR]

The future of offshore wind energy will be in deep waters. In this context, the main objective of the present paper is to develop a sensitivity analysis of a floating offshore wind farm. It will show how much the output variables can vary when the input variables are changing. For this purpose two different scenarios will be taken into account: the life-cycle costs involved in a floating offshore wind farm (cost of conception and definition, cost of design and development, cost of manufacturing, cost of installation, cost of exploitation and cost of dismantling) and the most important economic indexes in terms of economic feasibility of a floating offshore wind farm (internal rate of return, net present value, discounted pay-back period, levelized cost of energy and cost of power). Results indicate that the most important variables in economic terms are the number of wind turbines and the distance from farm to shore in the costs’ scenario, and the wind scale parameter and the electric tariff for the economic indexes. This study will help investors to take into account these variables in the development of floating offshore wind farms in the future. [ABSTRACT FROM AUTHOR]

Castro-Santos, L. and Diaz-Casas, V. 2015. Cost comparison of three floating offshore wind platforms. This paper proposes a method to calculate the total cost of a floating offshore wind farm. The method is based on the phases of the life cycle of such a farm. Each phase is defined by a cost, the value of which is either a constant or a variable parameter depending on the characteristics of a particular region. The tool so developed results in a georeferenced map of the total cost implied in the development of a floating offshore wind farm. Additionally, this method is applied to a floating offshore wind farm located in Galicia (in northwest Spain), as well as the three most important types of floating platforms: semisubmersible, tensioned leg, and spar. This paper is novel in that it helps to estimate the economics of floating offshore wind farms. In this sense, this study is one of the first of its kind to calculate the various costs associated with these types of wind farms. [ABSTRACT FROM AUTHOR]

The main objective of this paper is to establish an economic modelling of wave energy through a Geographical Information System (GIS). Furthermore, this method has been tested for the particular case of the Portuguese coast. It determines the best sea areas to install wave energy converters in this region, using spatial analysis of the Levelized Cost of Energy (LCOE). Several economic parameters, as capital or O&M costs, have been considered. In addition, a sensitivity analysis has been performed by varying the discount rate in three different scenarios. Several types of physical restrictions have been taken into account: bathymetry, submarine electrical cables, seabed geology, environmental conditions, protected areas in terms of heritage, navigation areas, seismic fault lines, etc. Spatial operations have been carried out to complete the procedure, using Model Builder of GIS software. Results indicate the most suitable areas in economic terms in Portugal to install wave energy devices. [ABSTRACT FROM AUTHOR]

The main developments in offshore wind power are focused on wind turbines with foundations on seabed. However, there exist important limitations for installing these structures exist in places with high depth within short distance from the coast. This means that the progress of offshore wind energy around the world is tied to the development of safety and low cost floating platforms for renewable energy offshore devices . Therefore, the first aim of this paper is to know which alternatives exist for a floating offshore wind farm establishment and design parameters are independent or dependent of platform configuration. In order to evaluate each alternative, the request inversion for each configuration has been analysed. From this point of view, the conclusion is that a string configuration for the electrical network is better than a star configuration. With regard to maintenance, it would be better to have a proper vessel only if the number of trips is more than three. [ABSTRACT FROM AUTHOR]

The objective of this article is to apply a method to determine the economic feasibility of floating offshore wind farms at Portugal continental coast. The method proposed has several phases: geographic, economic and restrictions. The objective of the geographic phase is to estimate the input variables that will be afterwards used to calculate the economic parameters in the economic phase. The restriction of bathymetry, the last stage, is then added to the economic maps previously calculated, whose value will be different depending on the floating offshore wind device chosen. In this study, two scenarios for electric tariff have been taken into consideration as well several floating offshore wind substructures: semisubmersible, TLP and spar. Results indicate what is the best floating offshore wind platform in terms of economic parameters and where is the best area, in the study region, to implement floating offshore wind farms. • a method to determine the economic feasibility of floating offshore wind farms at Portugal continental coast is applied. • The method proposed has several phases: geographic, economic and restrictions. • The restriction of bathymetry, the last stage, is then added to the economic maps previously calculated. • Two scenarios for electric tariff have been taken into consideration as well several floating offshore wind substructures. • Results indicate what is the best floating offshore wind platform in terms of economic parameters. [ABSTRACT FROM AUTHOR]

A technique to analyse the economic viability of offshore farms composed of wave energy converters is proposed. Firstly, the inputs, whose value will be considered afterwards in the economic step, was calculated using geographic information software. Secondly, the energy produced by each wave converter was calculated. Then the economic factors were computed. Finally, the restriction that considers the depth of the region (bathymetry) was put together with the economic outputs, whose value depends on the floating Wave Energy Converter (WEC). The method proposed was applied to the Cantabric and Atlantic coasts in the north of Spain, a region with a good offshore wave energy resource. In addition, three representative WECs were studied: Pelamis, AquaBuoy and Wave Dragon; and five options for electric tariffs were analysed. Results show the Wave Energy Converter that has the best results regarding its LCOE (Levelized Cost of Energy), IRR (Internal Rate of Return) and NPV (Net Present Value), and which area is best for the development of a wave farm. [ABSTRACT FROM AUTHOR]

This paper develops a methodology to determine the economic feasibility of implementing offshore wave energy farms on the Portuguese continental coast. This methodology follows several phases: the geographic phase, the energy phase, the economic phase, and the restrictions phase. First, in the geographic phase, the height and the period of the waves, the bathymetry, the distance from the farm to the shore, from farm to shipyard, and from farm to port, are calculated. In the energy phase the energy produced by each wave energy converter is determined, and in the economic phase, the parameters calculated in the previous phases are used as input to find the economic parameters. Finally, in the restrictions phase, a limitation by the bathymetry will be added to the economic maps, whose value will be different depending on the floating offshore wave energy converter (WEC). In this study, three wave energy converters have been considered, Pelamis, AquaBuOY, and Wave Dragon, and several scenarios for electric tariffs have been taken into account. The results obtained indicate what the best WEC is for this study in terms of its levelized cost of energy (LCOE), internal rate of return (IRR), and net present value (NPV), and where the best area is to install wave energy farms. [ABSTRACT FROM AUTHOR]

Abstract The present paper proposes a Computational Fluid Dynamics model to analyze the operation cycle and exhaust gas composition in a four-stroke marine diesel engine, the Wärtsilä 6L 46. Once validated, the numerical model was employed to study the influence of several pre-injection parameters such as pre-injection rate, duration, starting instant and number of pre-injections. The purpose is to reduce consumption and emissions, especially nitrogen oxides, due to the current increasingly restrictive legislation. It was found that the fuel injection is a critical factor influencing combustion and emission characteristics. Important nitrogen oxides emission reductions were obtained for the parameters analyzed. Particularly, a 31.9% nitrogen oxides reduction was obtained using 20% pilot injection, 65.7% advancing 4° the pre-injection start angle, 20.1% shorting 4° the pre-injection duration and 36.7% using 4 pre-injections. A slight increment of hydrocarbons, carbon monoxide and consumption was obtained, lower than 5% for almost all the cases analyzed, and a negligible effect on carbon dioxide emissions. Highlights • A CFD model was developed and validated using experimental data at different loads. • Several NOx reduction mechanisms were compared. • The effect of pre-injection rate, duration, starting instant and number was evaluated. • NOx, CO, HC and CO2 emissions as well as consumption were analyzed. [ABSTRACT FROM AUTHOR]

Studies on scientific winches installed on oceanographic/fisheries research vessels (ORVs and FRVs, respectively) are distinguished by the winches’ unique design features and the important role they play with scientific experiments. It is impossible to draw general conclusions when analysing scientific winches used for fisheries sampling experiments on recently built ORVs. Few vessels are built each year and their dimensions and mission vary greatly. Thus, to consider the concept of traction factor and the possible ways in which equipment on fishing trawlers could be arranged and manoeuvred, a statistical analysis was carried out on newly built and refitted vessels from Spanish shipyards. The starting point was a sample of 125 boats, to which linear regression models were adjusted to explain the relationship between total traction and the traction for the fishing winch. As a result, three regression models-one for each kind of arrangement-were obtained. The next step involved analysing and modelling the dependence of the auxiliary winch traction on fishing winch traction. [ABSTRACT FROM AUTHOR]

This article discusses the state of the art for driving technologies of anchor handling winches for offshore operations. These systems are necessary for anchor handling operations associated with installation of many types of moored floating offshore structures. To perform these operations, it is necessary to use specialized vessels known as AHT (Anchor Handling Tug) or AHTS (Anchor Handling Tug Supply) vessel, which incorporate specific equipment such as towing winches, but with higher performance than conventional tugs both in size and in technical performance. There are nowadays two main options for driving the Anchor Handling/Towing winches: hydraulic with low or high pressure motors, and electrical with AC motors driven by Variable Frequency Drives. Additionally, a new technology is appearing in the industrial sector which is starting to be applied in the marine sector, and in some cases for anchor handing winches: the permanent magnet motor. The aim of this paper is to discuss these driving technologies and their importance in the future of this part of the marine sector. [ABSTRACT FROM AUTHOR]