Regulating offshore wind energy

Offshore wind has become a large component of the renewable energy ambitions of many coastal states. Whereas onshore wind energy has a large visual impact on the landscape, offshore wind farms have fewer problems of this nature. Although this technology has historically been more expensive than its onshore counterpart, the cost reductions are promising – in part due to the larger areas available offshore, which allow for large economies of scale to be reached. After providing a factual background of offshore wind development, the chapter provides an overview of international law applicable to offshore wind farms. As the majority of offshore wind farms are located in the EU, the chapter also gives an overview of applicable EU law, before providing examples of different legislative options available to states throughout the lifetime of an offshore wind farm, based on a comparative overview of different national legislative systems for offshore wind

Short-term wind power prediction for offshore wind farms Evaluation of Fuzzy-Neural network based models

International audienceFuture major developments of wind power capacities are likely to take place offshore. As for onshore wind parks, short-term wind power prediction up to 48 hours ahead is expected to be of major importance for the management of offshore farms and their secure integration to the grid. Modeling the behavior of large wind farms of several tens or hundreds of MWs installed capacity and covering areas of several square kilometers is going to be a challenge. The adaptation of wind power forecasting methods to reach the specificities of the offshore case is not straightforward and very few results are available in the literature. The paper presents the new considerations that have to be made when dealing with large offshore wind farms and therefore the necessary evolutions of prediction models. Then, a state-of-the-art fuzzy-neural network based wind power forecasting model is described. Its performance is assessed for offshore conditions and compared to its level of performance for typical onshore parks. A general methodology dedicated to large offshore wind farms is developed. In order to deal with the spread of the turbines in such cases, methods based on the division of large wind farms into clusters are proposed. Furthermore, the use of satellite images for mapping the wind flow behavior inside offshore parks is investigated

Numerical Analysis of Offshore Wind Farm Wakes and their Impact on the Marine Boundary Layer

Given the rising number of offshore wind farms, the effect of wakes (the area downwind of wind farms characterized by a wind speed deficit) on downwind wind farms and their impact on the regional climate is discussed. This work investigates the spatial dimensions of wakes and the micrometeorological and regional climate impacts of offshore wind farms on the marine boundary layer based on mesoscale simulations using a wind farm parameterization (WFP) and airborne observations. WFPs act as a momentum sink for the mean flow. However, WFPs differ on whether or not they add additional turbulent kinetic energy (TKE) to represent the enhanced mixing caused by wind farms. This thesis uses for the first-time aircraft observations taken above and behind offshore wind farms to answer this uncertainty for stable conditions. The airborne measurements reveal that a TKE source and a horizontal resolution in the order of 5 km are necessary to represent the enhanced TKE (i.e. 20 times higher than in the ambient flow) above offshore wind farms. Further, this thesis evaluates the simulated spatial extent of a wake by the use of airborne measurements taken on 10 September 2016. Observations and simulations show a wake longer than 45 km associated with a warming and drying at hub height in the order of 0.5 K and 0.5 g kg-1, respectively. Vertical cross-sections perpendicular to the wake reveal that warmer and dryer air was mixed towards the surface due to an inversion located within the rotor area. An analysis of 23 additional airborne measurements executed within the far-field of offshore wind farms suggests that an impact on the temperature is only visible in case of inversions in the vicinity of the rotor area and wind speeds over 6 m s-1. Based on the successful evaluations above and downwind of offshore wind farms, this thesis explores a future scenario including all offshore wind farms possibly installed at the German Bight to discuss potential impacts of large offshore wind farms on the regional climate by considering two case studies. The simulations suggest that the wakes of large offshore wind farms clusters are longer than 100 km associated with changes in the sensible and latent heat flux. The net impact on the MABL depends on the inversion height and the temperature gradient between sea surface temperature (SST) and air temperature. Therefore, the dominating impact of offshore wind farms can only be determined by simulations covering several years with the constraint that the inversion height is captured by the driving mesoscale model

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

As the French government strives to achieve their offshore renewable energy target, the impact of offshore wind farms on coastal tourism in the Languedoc Rousillon is now being questioned. To assess this issue, a choice experiment was undertaken to elicit tourist preferences for wind turbines at different distances from the shore. We also examined whether potential visual nuisances may be compensated by wind farm associated reef-recreation or by adopting a coherent environmental policy. The findings indicate that age, nationality, vacation activities and their destination loyalty influence attitudes toward compensatory policies. Two policy recommendations are suggested. First, everything else being equal, wind farms should be located 12 km offshore. 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.

Floating offshore wind farms : demand planning & logistical challenges of electricity generation

Thesis (M. Eng. in Logistics)--Massachusetts Institute of Technology, Engineering Systems Division, 2009.Includes bibliographical references (leaf 46).Floating offshore wind farms are likely to become the next paradigm in electricity generation from wind energy mainly because of the near constant high wind speeds in an offshore environment as opposed to the erratic wind speeds in their onshore counterparts. By using floaters adapted from oilrigs, floating offshore wind farms can be operated with larger wind turbines for increased power generation. In the United States, floating offshore wind farms located off the coast of New England would be near large load centers and accessible to transmission load lines with low capacity utilization. Apart from the technological challenges of building floating offshore wind farms stemming from the developmental stage of the floater technology, there are three major logistical challenges prospective operators would likely encounter in harvesting electricity. The first challenge is to understand the interaction between distances from shore to locate a wind farm given increasing wind speeds. The second challenge is to understand the marginal impact of distance from shore on revenue generated from electricity sales from a floating offshore wind farm. And finally the third challenge is to determine inventory policy for wind turbine components in operating a floating offshore wind farm given its more complex operation and maintenance schedule. To address these challenges, this study examines a hypothetical 100 units of 5MW wind turbines to understand the economics of locating a floating offshore wind farm.(cont.) It is important to know the intersection between the increase in revenue generated with distance from shore and increase in operation & maintenance costs of a floating offshore wind farm. Because there is currently no floating offshore wind farm at the time of this writing, estimated failure rate data was used to study demand patterns for offshore wind turbine components. Three of maintenance strategies were examined. The results obtained from this work will serve as a blue print for prospective operators of floating offshore wind farms in logistics planning and inventory management of wind turbine components for electricity generation.by Christopher Dozie Nnadili.M.Eng.in Logistic

Sensitivity analysis of cost parameters for floating offshore wind farms: An application to Italian waters

Floating offshore wind farms represent the next frontier in wind power industry. However, the development of this technology is strongly dependent on its economic feasibility. There follows that the development of economic analyses is crucial to highlight the possible greater potential of floating offshore wind farms and to support their sustainability and technical value. In this context, the purpose of this paper is to present a sensitivity analysis of the main cost parameters for floating offshore wind farms, namely the distance from the coast, the distance from the closest port and the sea depth. It can give specific information on which parameters are more important, and how much they affect the total cost. To this aim, a comprehensive life cycle cost assessment of floating offshore wind farms has been developed. In this study the cost model has been applied to the Italian waters. The results shown should provide guidance on how to preliminary assess the quality of a given site for floating offshore wind farm installation, and should be helpful for future development of decision-making procedures in the offshore wind sector

Control and operation of multi-terminal DC systems for integrating large offshore wind farms

This paper discusses control and operation of multi-terminal DC systems for integrating large offshore wind farms. It was presented at the 7th International Workshop on Large-Scale Integration of Wind Power and Transmission Networks for Offshore Wind Farms in 2008

DC collection networks for offshore generation

Onshore wind farms can now be regarded as a mature technology, capable of providing increasing levels of clean energy. The development of offshore wind technology will provide the ability to harness much larger wind energy resource. Offshore wind arrays present many new challenges including the electrical power system which provides the internal collection system and the connection to the on-shore power network. For remote offshore wind farms, high voltage direct current (HVDC) transmission will be required to transmit power from the wind farm to the shore. The use of HVDC has the effect of decoupling the wind farms internal collection network from the rest of the power grid, thereby removing the requirement for a conventional alternating current (AC) network. This paper discusses the use of a direct current (DC) collection system for offshore wind farms, with particulars emphasis of DC-DC converter requirements. The proposed converter is validated by the simulation model and the performances e.g. switching losses, conduction losses are investigated

Perspectives on offshore wind farms development in Great Lakes

Global warming emissions and carbon dioxide caused by human activities are overloading our atmosphere which cause web of significant and harmful impacts. There are little to no global warming emissions by renewable energy. To date, offshore wind farms generally have been installed in shallow ocean-coastal areas. The Great Lakes with freshwater have shown high potential for installing offshore wind farms, and significant advantages. There are more than 5 offshore windfarms in progress at the end of 2019 in Great Lakes. The object of this study is to present the capacity and prospects of offshore wind farms development in Great Lakes. Also, the power of wind farms, barriers, issues, wind vision, advantages and disadvantages, the criteria related to the location of the offshore wind farms in Great Lakes have been analyzed and presents statistics for decision-makers, interested communities, investors and academic researchers. This paper is among the rare works that have been done in aspect of statistical and data gathering for the wind offshore in Great Lakes as the moratorium in the Canadian side and the difficulties in obtaining permissions in the American side put the offshore wind sector on pause for a long time, and recently (since 2016) it started to get some momentum. The research has been conducted based on the analysis of acts, regulations, the subject’s literature and information from websites

Hybrid Versus Radial Offshore Wind Connections: Power Grid Investments in the North Sea

To enable offshore wind in the North Sea to take a key, rapid role in the European energy transition, massive grid expansions and investments are required. We consider the impact of such grid expansion in the North Sea on the future European power prices. To this end, we compare, using the power-system model EMPIRE, a scenario in which wind farms can only connect to their own countries, and a scenario in which the wind farms can connect both to other countries and all other wind farms. Uncertainty is implemented in the hourly power load as well as the renewable power production in each system node. The nodes in this work represent the countries in the European power system as well as the major wind farm projects in the North Sea.Our results indicate that allowing the offshore wind farms to connect to other countries and wind farms can have a significant impact on the power prices in the different prize zones. These observed effects depend on the level of investments in the North Sea wind farms. Furthermore, allowing for interconnections between countries through the North Sea wind farms significantly increases the investments in the North Sea by means of much larger wind farm capacities and comprehensive grid development. Our results also highlight how certain offshore wind farm nodes may be mainly used for electric power export, rather than covering the domestic power demand. For such wind farms, an interconnected North Sea grid will be critical for attracting large-scale offshore wind investments.Hybrid Versus Radial Offshore Wind Connections: Power Grid Investments in the North SeaacceptedVersio