Identifying space for offshore wind energy in the North Sea. Consequences of scenario calculations for interactions with other marine uses

The increasing demand for renewable energy drives the development of offshore wind energy (OWE) leading to competing claims with other human and nature related uses of the North Sea. This paper investigates possibilities to identify space for new OWE while minimising effects on other uses. An inventory is made of the major uses in the Central and Southern North Sea, including the expected development towards 2030. The spatial distribution of non-wind uses is determined as well as the possibilities for differentiation based on density, economic value or nature value and co-existence. These possibilities are translated into calculation rules quantifying the relative importance. These calculation rules have been incorporated in a Decision Support System (DSS) to analyse how the priority of OWE development could impact non-wind uses. In a low OWE priority scenario consequences for other use was found to be very limited, with fisheries and wildlife affected most. In a high OWE priority scenario a considerable amount of OWE may be developed with substantial claims on sand extraction and military use areas and a shift towards higher value categories for shipping and fisheries. Relocation and co-existence of uses are important means to reduce the impact of increased OWE development.     

Technological learning in offshore wind energy: Different roles of the government

Offshore wind energy is a promising source of renewable electricity, even though its current costs prevent large-scale implementation. Technological learning has improved the technology and its economic performance already, and could result in significant further improvements. This study investigates how technological learning takes place in offshore wind energy and how technological learning is related to different policy regimes. Offshore wind energy developments in Denmark and the United Kingdom have been analysed with a technology-specific innovation systems approach. The results reveal that the dominant forms of learning are learning by doing and learning by using. At the same time, learning by interacting is crucial to achieve the necessary binding elements in the technology-specific innovation system. Generally, most learning processes were performed by self-organizing entities. However, sometimes cultural and technical barriers occurred, excluding component suppliers and knowledge institutes from the innovation system. Danish policies successfully anticipated these barriers and removed them; therefore, the Danish policies can be characterized as pro-active. British policies shaped stable conditions for learning only; therefore, they can be characterized as active. In the future, barriers could hinder learning by interacting between the oil and gas industry, the offshore wind industry and academia. Based on this study, we suggest national and international policy makers to design long-term policies to anticipate these barriers, in order to contribute to technological learning.     

The offshore trend: Structural changes in the wind power sector

In recent years, the wind power sector has begun to move offshore, i.e. to use space and good wind speeds on the open sea for large scale electricity generation. Offshore wind power, however, is not just technologically challenging but also a capital intensive and risky business that requires particular financial and organizational resources not all potential investors might have. We therefore address the question, what impact offshore wind power may have on ownership and organizational structures in the wind power sector. We compare on- and offshore wind park ownership in Denmark, the UK and Germany. The analysis shows that offshore wind power in all three countries is dominated by large firms, many of which are from the electricity sector. In Denmark and the UK, also investors from the gas and oil industry play an important role in the offshore wind business. This development represents a major shift for countries such as Germany and Denmark, in which the wind power sector has grown and matured on the basis of investments by individuals, farmers, cooperatives and independent project developers. The structural changes by which offshore wind power is accompanied have consequences for turbine manufacturers, project developers, investors, associations and policy makers in the field.     

Economics of producing hydrogen as transportation fuel using offshore wind energy systems

Over the past few years, hydrogen has been recognized as a suitable substitute for present vehicular fuels. This paper covers the economic analysis of one of the most promising hydrogen production methods—using wind energy for producing hydrogen through electrolysis of seawater—with a concentration on the Indian transport sector. The analysis provides insights about several questions such as the advantages of offshore plants over coastal installations, economics of large wind-machine clusters, and comparison of cost of producing hydrogen with competing gasoline. Robustness of results has been checked by developing several scenarios such as fast/slow learning rates for wind systems for determining future trends. Results of this analysis show that use of hydrogen for transportation is not likely to be attractive before 2012, and that too with considerable learning in wind, electrolyzer and hydrogen storage technology.     

Simulation of electricity supply of an Atlantic island by offshore wind turbines and wave energy converters associated with a medium scale local energy storage

The problem of sizing an electricity storage for a 5000 inhabitants island supplied by both marine renewables (offshore wind and waves) and the mainland grid is addressed by a case study based on a full year resource and consumption data. Generators, transmission lines and battery storage are accounted for through basic simplified models while the focus is put on electricity import/export budget. Self-sufficiency does not seem a reasonable goal to pursue, but partial autonomy provided by renewable sources and a medium size storage would probably be profitable to the island community.     

Continuous spatial modelling to analyse planning and economic consequences of offshore wind energy

Offshore wind resources appear abundant, but technological, economic and planning issues significantly reduce the theoretical potential. While massive investments are anticipated and planners and developers are scouting for viable locations and consider risk and impact, few studies simultaneously address potentials and costs together with the consequences of proposed planning in an analytical and continuous manner and for larger areas at once. Consequences may be investments short of efficiency and equity, and failed planning routines. A spatial resource economic model for the Danish offshore waters is presented, used to analyse area constraints, technological risks, priorities for development and opportunity costs of maintaining competing area uses. The SCREAM-offshore wind model (Spatially Continuous Resource Economic Analysis Model) uses raster-based geographical information systems (GIS) and considers numerous geographical factors, technology and cost data as well as planning information. Novel elements are weighted visibility analysis and geographically recorded shipping movements as variable constraints. A number of scenarios have been described, which include restrictions of using offshore areas, as well as alternative uses such as conservation and tourism. The results comprise maps, tables and cost-supply curves for further resource economic assessment and policy analysis. A discussion of parameter variations exposes uncertainties of technology development, environmental protection as well as competing area uses and illustrates how such models might assist in ameliorating public planning, while procuring decision bases for the political process. The method can be adapted to different research questions, and is largely applicable in other parts of the world.     

Techno-economic feasibility of fleets of far offshore hydrogen-producing wind energy converters

Innovative solutions need to be developed for harvesting wind energy far offshore. They necessarily involve on-board energy storage because grid-connection would be prohibitively expensive. Hydrogen is one of the most promising solutions. However, it is well-known that it is challenging to store and transport hydrogen which may have a critical impact on the delivered hydrogen cost.In this paper, it is shown that there are vast areas far offshore where wind power is both characterized by high winds and limited seasonal variations. Capturing a fraction of this energy could provide enough energy to cover the forecast global energy demand for 2050. Thus, scenarios are proposed for the exploitation of this resource by fleets of hydrogen-producing wind energy converters sailing autonomously. The scenarios include transportation and distribution of the produced hydrogen.The delivered hydrogen cost is estimated for the various scenarios in the short term and in the longer term. Cost estimates are derived using technical and economic data available in the literature and assumptions for the cost of electricity available on-board the wind energy converters. In the shorter term, delivered cost estimates are in the range 7.1–9.4 €/kg depending on the scenario and the delivery distance. They are based on the assumption of on-board electricity cost at 0.08€/kWh. In the longer term, assuming an on-board electricity cost at 0.04€.kWh, the cost estimates could reduce to 3.5 to 5.7 €/kg which would make the hydrogen competitive on several hydrogen markets without any support mechanism. For the hydrogen to be competitive on all hydrogen markets including the ones with the highest GHG emissions, a carbon tax of approximately 200 €/kg would be required.     

Impact of the oil price and fiscal facilities on offshore mining at the Dutch Continental Shelf

The surge in the oil price has raised questions about the magnitude of global reserves of oil. According to some analysts, the current high oil prices indicate a looming decline in the global production of oil. Others believe, however, that the increased level of the oil price encourages exploration and production activities, bringing the oil price to a lower equilibrium level in the near future.     

From laggard to leader: Explaining offshore wind developments in the UK

Offshore wind technology has recently undergone rapid deployment in the UK. And yet, up until recently, the UK was considered a laggard in terms of deploying renewable energy. How can this burst of offshore wind activity be explained? An economic analysis would seek signs for newfound competitiveness for offshore wind in energy markets. A policy analysis would highlight renewable energy policy developments and assess their contribution to economic prospects of offshore wind. However, neither perspective sheds sufficient light on the advocacy of the actors involved in the development and deployment of the technology. Without an account of technology politics it is hard to explain continuing policy support despite rising costs. By analysing the actor networks and narratives underpinning policy support for offshore wind, we explain how a fairly effective protective space was constructed through the enroling of key political and economic interests.     

Unravelling historical cost developments of offshore wind energy in Europe

This paper aims to provide insights in the cost developments of offshore wind energy in Europe. This is done by analysing 46 operational offshore wind farms commissioned after 2000. An increase of the Capital Expenditures (CAPEX) is found that is linked to the distance to shore and depth of more recent wind farms and commodity prices. Analysis results indicate that these two factors are only responsible for about half of the observed CAPEX increase, suggesting other factors such as turbine market with limited competition also led to an increasing CAPEX. Using CAPEX, Annual Energy Production, Financings costs and Operational Expenditures, the development of average Levelized Cost of Electricity (LCoE) is shown to increase from 120 €/MWh in 2000 towards 190 €/MWh in 2014, which is a direct result of the CAPEX increase. The results indicate very different LCoE values among European countries, from currently about 100 Euro/MWh in Denmark and Sweden to 150-220 Euro/MWh in all other countries investigated suggesting an effect of national policy frameworks on the LCoE of offshore wind energy.     

Windstorm risk assessment for offshore wind farms in the North Sea

The North Sea is becoming increasingly attractive to wind energy developers and investors, with 38 wind farms belonging to five different countries and representing over€35 billion of assets. Concerns about offshore wind turbines being damaged by extreme windstorms pose a challenge to insurers, investors and regulators. Catastrophe modeling can adequately quantify the risk. In this study, a Monte Carlo simulation approach is used to assess the number of turbines that buckle using maximum wind speeds reaching each wind farm. Damage assessment is undertaken for each wind farm using a log‐logistic damage function and a left‐truncated Weibull distribution. The risk to offshore wind power in the North Sea is calculated using an exceedance probability (EP) curve for the portfolio of wind farms. The European Union Solvency II directive requires insurance companies to hold sufficient capital to guard against insolvency. The solvency capital requirement (SCR) is based on a value‐at‐risk measure calibrated to a 99.5% confidence level over a 1‐year time horizon. The SCR is estimated at €0.049 billion in the case of yawing turbines. Simulations are repeated for different climate change scenarios. If wind speeds grow by 5% and the frequency of storms increases by 40%, the SCR is seen to rise substantially to €0.264 billion. Relative to the total value of assets, the SCR is 0.14% compared with 0.08% for European property, confirming that these wind farm assets represent a relatively high risk. Furthermore, climate change could increase the relative SCR to levels as high as 0.75%.     

One style to build them all: Corporate culture and innovation in the offshore wind industry

This study explores how Vestas and Siemens Wind Power manage technological innovation in the offshore wind power industry. It utilizes the concept of open and closed “research styles” to investigate how each company designs, constructs, and maintains offshore wind turbines. The article starts by summarizing three of the main innovation challenges facing the offshore wind sector—harsh conditions, capital intensity, and production bottlenecks—before it delves into the specific details about how Vestas and Siemens Wind Power approach turbine development. It divides this discussion into six distinct segments: resources and expenditures, stakeholder involvement and collaboration, testing and maintenance, control and knowledge management, adaptability of designs, and customization and marketing. The study finds that both Vestas and SWP, despite their corporate and cultural differences, utilize the same elements of closed and open styles. It lastly suggests that the notion of style itself may challenge certain assumptions held by scholars about managing the research and innovation process.     

A review on development of offshore wind energy conversion system

Wind energy conversion system, aiming to convert mechanical energy of air flow into electrical energy has been widely concerned in recent decades. According to the installation sites, the wind energy conversion system can be divided into land-based wind conversion system and offshore wind energy conversion (OWEC) system. Compared to land-based wind energy technology, although OWEC started later, it has attracted more attentions due to its significant advantages in sufficient wind energy, low wind shear, high power output and low land occupancy rate. In this paper, the principle of wind energy conversion and the development status of offshore wind power in the world are briefly introduced at first. And then, the advantages and disadvantages of several offshore wind energy device (OWED), such as horizontal axis OWED, vertical axis OWED and cross axis OWED are compared. Subsequently, several major constraints, such as complex marine environment, deep-sea power transmission and expensive cost of equipment installation faced by offshore wind conversion technology are presented and comprehensively analysed. Finally, based on the summary and analysis of some emerging technologies and the current situation of offshore wind energy utilization, the development trend of offshore wind power is envisioned. In the future, it is expected to witness multi-energy complementary, key component optimization and intelligent control strategy for smooth energy generation of offshore wind power systems.     

Accessibility assessment for operation and maintenance of offshore wind farms in the North Sea

Focused on offshore wind energy operation and maintenance applications, this work presents a detailed accessibility analysis of the North Sea. After a review of existing normative dedicated to inspection and access of offshore wind turbines, a rigorous mathematical formulation of relevant accessibility parameters is given by means of the set theory. Long‐term and high‐resolution metocean data are extracted from reanalysis databases and used to evaluate spatial and temporal variability of such parameters. Respectively restricted by significant wave height and mean wind speed, access by workboat and helicopter is evaluated. Being affected by both wave height and wind speed. Access by offshore crane is also analyzed. It resulted that the UK coast and the southern region of the North Sea are highly accessible, while the coast of Denmark and Norway undergoes more severe metocean conditions. This is, however, balanced by a higher wind resource. Moreover, a strong seasonality is ascertained, together with a drastic reduction of accessibility during daytime in a vast part of the basin. Accessibility during daytime in winter and autumn is very difficult for the whole North Sea. Among the studied farms, Dogger Bank is by far the one with the highest resource and lowest accessibility, while Thorntonbank III the one with the lowest resource and highest accessibility. In addition, accessibility is non‐linearly related to wind speed and wave height limits chosen for the access strategies covered. Copyright © 2016 John Wiley & Sons, Ltd.     

Offshore wind energy in the world context

The interest for the exploitation of the offshore wind energy is growing in Europe, where man land use is very high resulting in strong limitation to the installation of onshore wind farms. The today offshore operating wind power is 12 MW, with two wind farms in Denmark and one in Netherlands; it starts to be significant (0.6%) in terms of the onshore power, 2000 MW in Europe.In the world the onshore installed wind power is exceeding 4000 MW, but not so much up to now has been done on the offshore area outside Europe.The European four years experience on the prototypical offshore wind farms looks significantly promising and suggests to promote a similar approach in many densely populated coastal countries in the world with high electricity demand.Results of studies are presented on the offshore wind potential in the European countries and of the tentative evaluation for the Mediterranean basin, and the seas of USA and China. A review is made of the offshore applications, particularly for the Nothern European seas.Economy and environmental trends are illustrated in parallel to those of maturing offshore technology. It is suggested to prepare an action plan to promote the development of the offshore applications in the world context.     

Multidisciplinary design optimization of offshore wind turbines for minimum levelized cost of energy

This paper presents a method for multidisciplinary design optimization of offshore wind turbines at system level. The formulation and implementation that enable the integrated aerodynamic and structural design of the rotor and tower simultaneously are detailed. The objective function to be minimized is the levelized cost of energy. The model includes various design constraints: stresses, deflections, modal frequencies and fatigue limits along different stations of the blade and tower. The rotor design variables are: chord and twist distribution, blade length, rated rotational speed and structural thicknesses along the span. The tower design variables are: tower thickness and diameter distribution, as well as the tower height. For the other wind turbine components, a representative mass model is used to include their dynamic interactions in the system. To calculate the system costs, representative cost models of a wind turbine located in an offshore wind farm are used. To show the potential of the method and to verify its usefulness, the 5 MW NREL wind turbine is used as a case study. The result of the design optimization process shows 2.3% decrease in the levelized cost of energy for a representative Dutch site, while satisfying all the design constraints.     

GHG emissions and energy performance of offshore wind power

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.     

A comparison of offshore wind power development in europe and the U.S.: Patterns and drivers of development

Since the turn of the 21^st century, the onshore wind industry has seen significant growth due to the falling cost of wind generated electricity. This growth has coincided with an interest in the development of offshore wind farms. In Europe, governments and developers have begun establishing small to medium sized wind farms offshore to take advantage of stronger and more constant winds and the relative lack of landowner conflicts. In the U.S., several developers are in the planning and resource evaluation phases of offshore wind farm development, but no wind farms are currently operational or under construction. In this paper, we analyze the patterns of development in Europe and compare them to the U.S. We find significant differences in the patterns of development in Europe and the U.S. which may impact the viability of the industry in the U.S. We also discuss the policies used by European nations to stimulate offshore wind development and we discuss the potential impacts of similar policies in the U.S.     

Reliability-based layout optimization in offshore wind energy systems

Existing methods for optimizing wind array layouts typically use power or cost objectives and rarely consider reliability-based objectives. Component and system failure rates, however, are dependent on location-specific wind conditions, are influenced by array layout and wake interactions, and have a direct and significant impact on capital costs, operational costs, and power production. Although wind power plant models exist that calculate wind loads with sufficient resolution to capture component loading dynamics from wind conditions, they are computationally expensive and thus not suitable for research applications requiring many evaluations, particularly optimization. This study describes the development of computationally efficient, reliability-based layout optimization methods, enabling us to explore the relationship between component reliability and layout optimization. These methods include the surrogate modeling of the planet bearing life based on varying wind conditions simulated in FAST.Farm and the formulation of reliability-based objectives based on failure cost and power production models. Through demonstration of this method, we explore how wind conditions, objective functions, and capacity density influence reliability-based layout optimization. Results indicate that considering reliability alongside power production can reduce failure costs associated with replacement costs and downtime whilemaintaining or improving power production. Our conclusions highlight the opportunity for wind power plant developers to integrate reliability and operational expenditures alongside performance and capital expenditure objectives in plant design and development to improve plant performance and costs.     

Conflict in the Sea of Trafalgar: offshore wind energy and its context

This paper analyses a participatory process related to the plan to construct an offshore wind farm in the Sea of Trafalgar, off the coast of Cádiz, in Andalucía (southern Spain). This case study shows the complexities of public participation in energy development, indicating the vital importance of context. The stakeholders' values and attitudes in the controversy are highly dependent on the specific situation, including the concrete characteristics of the project proposal. In fact, they may diverge sharply from the stakeholders' core beliefs. It is important for decision making to take account of this contextual and dynamic element in stakeholder behavior, contrary to suppositions of static and predetermined behavior. Copyright © 2010 John Wiley & Sons, Ltd.