scholarly journals Risk-Adjusted Discount Rate and Its Components for Onshore Wind Farms at the Feasibility Stage

Energies ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6840
Author(s):  
Piotr W. Saługa ◽  
Krzysztof Zamasz ◽  
Zdzisława Dacko-Pikiewicz ◽  
Katarzyna Szczepańska-Woszczyna ◽  
Marcin Malec
Keyword(s):  
Discount Rate ◽  
Wind Farm ◽  
A Priori ◽  
Flow Analysis ◽  
Wind Farms ◽  
Capital Budgeting ◽  
Cost Of Equity ◽  
Discussion Section ◽  
Onshore Wind ◽  
Starting Point

The concept of risk is well known in the energy sector. It is normally recognized when it comes to price and cost forecasting, annual production calculation, or evaluating project lifetime. Nevertheless, it should be pointed out that the quantitative evaluation of risk is usually difficult. The discount rate is the only parameter reflecting risk in the discounted cash flow analysis. Therefore, knowledge of the discount rate along with the major components affecting its level is of fundamental significance for making investment decisions, capital budgeting, and project management. By referring to the standard coal-fired power generation projects the authors of the paper tackle the analysis of the composition of discount rate for onshore wind farm technologies in the Polish conditions. The study was carried out on the basis of a typical (hypothetical) onshore wind farm project assessed at the feasibility stage. To enable comparisons and discussions, it was assumed that the best reference point for such purposes is the real risk-adjusted discount rate, RADR, after-tax, in all equity evaluations (the ‘bare bones’ assumption); that is because such a rate reflects the inherent characteristics of the project risk. The study methodology involves the a priori application of the discount rate level and subsequently—in an analytical way—calculation of its individual components. The starting point for the analysis of the RADR’s composition was the definition of risk, understood as the product of uncertainty and consequences. Then, the risk factors were adopted and level of uncertainty assessed. Subsequently, using the classical sensitivity analysis of IRR, the consequences (as slopes of sensitivity lines) were calculated. Consequently, risk portions in percentage forms were received. Eventually, relative risks and risk components within cost of equity were assessed. Apart from the characteristics of the discount rate at the feasibility stage, in the discussion section the study was supplemented with an analogous analysis of the project’s cost of equity at the operating stage.

Community Benefits and UK Offshore Wind Farms: Evolving Convergence in a Divergent Practice

2021 ◽  
pp. 2150001
Author(s):  
John Glasson
Keyword(s):  
Wind Farm ◽  
Wind Farms ◽  
Host Community ◽  
Offshore Wind ◽  
Energy Industry ◽  
Offshore Wind Farms ◽  
Onshore Wind ◽  
Community Benefits ◽  
The Uk ◽  
Renewable Energy Industry

The Offshore Wind sector is a major, dynamic, and rapidly evolving renewable energy industry. This is particularly so in Europe, and especially in the UK. Associated with the growth of the industry has been a growth of interest in community benefits as voluntary measures provided by a developer to the host community. However, in many cases, and for some of the large North Sea distant offshore wind farms, the benefits packages have been disparate and pro rata much smaller than for the well-established onshore wind farm industry. However, there are signs of change. This paper explores the issues of community benefits for the UK offshore sector and evolving practice, as reflected in a macro study of the adoption of community benefits approaches across the industry. This is followed by a more in-depth micro- approach, which explores approaches that have been adopted in three case studies of recent OWF projects — Aberdeen, Beatrice and the Hornsea Array. Whilst there is still much divergence in practice, there are also examples of some convergence, and the development of a more replicable practice. Particularly notable is the adoption of annual community benefits funds, as the key element of community benefits schemes/agreements between developers, local authorities and local communities.

scholarly journals Field experiment for open-loop yaw-based wake steering at a commercial onshore wind farm in Italy

2020 ◽  
Author(s):  
Bart M. Doekemeijer ◽  
Stefan Kern ◽  
Sivateja Maturu ◽  
Stoyan Kanev ◽  
Bastian Salbert ◽  
...  
Keyword(s):  
Field Experiment ◽  
Wind Farm ◽  
Wind Farms ◽  
Power Production ◽  
Field Trials ◽  
Open Loop ◽  
Onshore Wind ◽  
Power Maximization ◽  
Energy Gains ◽  
Turbine Arrays

Abstract. The concept of wake steering in wind farms for power maximization has gained significant popularity over the last decade. Recent field trials described in the literature demonstrate the real potential of wake steering on commercial wind farms, but also show that wake steering does not yet consistently lead to an increase in energy production for all inflow conditions. Moreover, a recent survey among experts shows that validation of the concept remains the largest barrier for adoption currently. In response, this article presents the results of a field experiment investigating wake steering in three-turbine arrays at an onshore wind farm in Italy. This experiment was performed as part of the European CL-Windcon project. The measurements show increases in power production of up to 35 % for two-turbine interactions and up to 16 % for three-turbine interactions. However, losses in power production are seen for various regions of wind directions too. In addition to the gains achieved through wake steering at downstream turbines, more interesting to note is that a significant share in gains are from the upstream turbines, showing an increased power production of the yawed turbine itself compared to baseline operation for some wind directions. Furthermore, the surrogate model, while capturing the general trends of wake interaction, lacks the details necessary to accurately represent the measurements. This article supports the notion that further research is necessary, notably on the topics of wind farm modeling and experiment design, before wake steering will lead to consistent energy gains in commercial wind farms.

Optimization of Floating Offshore Wind Energy Systems Using an Extended Pattern Search Method

2016 ◽  
Author(s):  
Caitlin Forinash ◽  
Bryony DuPont
Keyword(s):  
Wind Farm ◽  
Wind Farms ◽  
Power Production ◽  
Pattern Search ◽  
Offshore Wind ◽  
Offshore Wind Farm ◽  
Power Development ◽  
Offshore Wind Farms ◽  
Onshore Wind ◽  
Extended Pattern Search

An Extended Pattern Search (EPS) approach is developed for offshore floating wind farm layout optimization while considering challenges such as high cost and harsh ocean environments. This multi-level optimization method minimizes the costs of installation and operations and maintenance, and maximizes power development in a unidirectional wind case by selecting the size and position of turbines. The EPS combines a deterministic pattern search algorithm with three stochastic extensions to avoid local optima. The EPS has been successfully applied to onshore wind farm optimization and enables the inclusion of advanced modeling as new technologies for floating offshore wind farms emerge. Three advanced models are incorporated into this work: (1) a cost model developed specifically for this work, (2) a power development model that selects hub height and rotor radius to optimize power production, and (3) a wake propagation and interaction model that determines aerodynamic effects. Preliminary results indicate the differences between proposed optimal offshore wind farm layouts and those developed by similar methods for onshore wind farms. The objective of this work is to maximize profit; given similar parameters, offshore wind farms are suggested to have approximately 24% more turbines than onshore farms of the same area. EPS layouts are also compared to those of an Adapted GA; 100% efficiency is found for layouts containing twice as many turbines as the layout presented by the Adapted GA. Best practices are derived that can be employed by offshore wind farm developers to improve the layout of platforms, and may contribute to reducing barriers to implementation, enabling developers and policy makers to have a clearer understanding of the resulting cost and power production of computationally optimized farms; however, the unidirectional wind case used in this work limits the representation of optimized layouts at real wind sites. Since there are currently no multi-turbine floating offshore wind farm projects operational in the United States, it is anticipated that this work will be used by developers when planning array layouts for future offshore floating wind farms.

scholarly journals Aligned and Staggered Layouts: What is the Impact on Wind Farms Land-Use?

2020 ◽  
Author(s):  
Rafael Valotta Rodrigues ◽  
Corinne Lengsfeld
Keyword(s):  
Land Use ◽  
Output Power ◽  
Wind Farm ◽  
Wind Farms ◽  
Short Term ◽  
Continuous Increase ◽  
Onshore Wind ◽  
Wake Interaction ◽  
The Impact ◽  
Blade Element

The use of wind energy has been developing fast over the last years. The global cumulative wind power capacity increased by 10.5% in 2019, most of which comes from onshore wind farms. One of the consequences of this continuous increase is the use of land for onshore wind farms. There are already cases worldwide where lack of well-established plans and strategies have caused delays in projects. The need for efficiently using land for wind farms will be mandatory in the short term. In this work, we present a numerical analysis to evaluate wind farm land-use. By defining the ratio between mechanical output power over an area as a parameter called land-use ratio, this work focused on comparing several cases of aligned and staggered layouts. Mechanical output power was estimated using a validated code based on Blade Element Momentum code, and the wake velocities and wake interaction effects were estimated using a validated wind turbine CFD model. In terms of output power, staggered designs are more efficient than aligned designs. However, the results showed that even though staggered designs produced higher output power, aligned farms with tight lateral spacing could be as efficient as staggered ones in terms of land-use but using fewer turbines. In summary, tightly aligned designs should be a tendency in the future towards efficient use of land in wind farms.

Flow Simulation Around a Rim-Driven Wind Turbine and in Its Wake

2013 ◽  
Author(s):  
Bryan E. Kaiser ◽  
Svetlana V. Poroseva ◽  
Michael A. Snider ◽  
Rob O. Hovsapian ◽  
Erick Johnson
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Wind Farm ◽  
Flow Simulation ◽  
Wind Farms ◽  
Sensitivity Study ◽  
Onshore Wind ◽  
Flow Simulations ◽  
Turbine Design ◽  
The Impact

A relatively high free stream wind velocity is required for conventional horizontal axis wind turbines (HAWTs) to generate power. This requirement significantly limits the area of land for viable onshore wind farm locations. To expand a potential for wind power generation and an area suitable for onshore wind farms, new wind turbine designs capable of wind energy harvesting at low wind speeds are currently in development. The aerodynamic characteristics of such wind turbines are notably different from industrial standards. The optimal wind farm layout for such turbines is also unknown. Accurate and reliable simulations of a flow around and behind a new wind turbine design should be conducted prior constructing a wind farm to determine optimal spacing of turbines on the farm. However, computations are expensive even for a flow around a single turbine. The goal of the current study is to determine a set of simulation parameters that allows one to conduct accurate and reliable simulations at a reasonable cost of computations. For this purpose, a sensitivity study on how the parameters variation influences the results of simulations is conducted. Specifically, the impact of a grid refinement, grid stretching, grid cell shape, and a choice of a turbulent model on the results of simulation of a flow around a mid-sized Rim Driven Wind Turbine (U.S. Patent 7399162) and in its near wake is analyzed. This wind turbine design was developed by Keuka Energy LLC. Since industry relies on commercial software for conducting flow simulations, STAR-CCM+ software [1] was used in our study. A choice of a turbulence model was made based on the results from our previous sensitivity study of flow simulations over a rotating disk [2].

Response Surface Based Cost Model for Onshore Wind Farms Using Extended Radial Basis Functions

2010 ◽  
Author(s):  
Jie Zhang ◽  
Souma Chowdhury ◽  
Achille Messac ◽  
Luciano Castillo ◽  
Jose Lebron
Keyword(s):  
Response Surface ◽  
Radial Basis Functions ◽  
Wind Farm ◽  
Cost Model ◽  
Wind Farms ◽  
Labor Cost ◽  
Basis Functions ◽  
Onshore Wind ◽  
Radial Basis ◽  
The Cost

This paper develops a cost model for onshore wind farms in the U.S.. This model is then used to analyze the influence of different designs and economic parameters on the cost of a wind farm. A response surface based cost model is developed using Extended Radial Basis Functions (E-RBF). The E-RBF approach, a combination of radial and non-radial basis functions, can provide the designer with significant flexibility and freedom in the metamodeling process. The E-RBF based cost model is composed of three parts that can estimate (i) the installation cost, (ii) the annual Operation and Maintenance (O&M) cost, and (iii) the total annual cost of a wind farm. The input parameters for the E-RBF based cost model include the rotor diameter of a wind turbine, the number of wind turbines in a wind farm, the construction labor cost, the management labor cost and the technician labor cost. The accuracy of the model is favorably explored through comparison with pertinent real world data. It is found that the cost of a wind farm is appreciably sensitive to the rotor diameter and the number of wind turbines for a given desirable total power output.

Studies on integration of different capacity offshore wind farms in power grid

2020 ◽  
pp. 0309524X2097849
Author(s):  
Mohammad Mushir Riaz ◽  
Badrul Hasan Khan
Keyword(s):  
Wind Farm ◽  
Grid Point ◽  
Flow Analysis ◽  
Coastal Region ◽  
Wind Farms ◽  
Load Flow ◽  
Offshore Wind ◽  
Offshore Wind Farms ◽  
Load Flow Analysis ◽  
Suitable Site

This work is in continuation of our earlier pre-feasibility study that was carried out to investigate the prospects of constructing an offshore wind farm in the coastal region of south India. After selection of the suitable site and optimal wind turbine, another challenge was to penetrate wind energy in the grid. The present study aims to select an economical and technically feasible connection point in the test grid for wind farm integration. For each of the seven available connection points, load flow analysis was done using MATLAB, to assess how grid reacts to the power produced by different capacity wind farms. Results of the present study suggest that the offshore wind farms consisting of 10 to 23 turbines (RE power 6.2M), may be connected at grid point C, where the voltage level after penetration of wind farm was found to be within the acceptable range.

scholarly journals Local turbulence parameterization improves the Jensen wake model and its implementation for power optimization of an operating wind farm

2018 ◽  
Author(s):  
Thomas Duc ◽  
Olivier Coupiac ◽  
Nicolas Girard ◽  
Gregor Giebel ◽  
Tuhfe Göçmen
Keyword(s):  
Wind Turbine ◽  
Wind Farm ◽  
Decay Constant ◽  
Wind Farms ◽  
Power Production ◽  
Original Model ◽  
Offshore Wind ◽  
Offshore Wind Farm ◽  
Onshore Wind ◽  
Wake Model

Abstract. In this paper, a new calculation procedure to improve the accuracy of the Jensen wake model for operating wind farms is proposed. In this procedure the wake decay constant is updated locally at each wind turbine based on the turbulence intensity measurement provided by the nacelle anemometer. This procedure was tested against experimental data at onshore wind farm La Sole du Moulin Vieux (SMV) in France and the offshore wind farm Horns Rev-I in Denmark. Results indicate that the wake deficit at each wind turbine is described more accurately than when using the original model, reducing the error from 15–20 % to approximately 5 %. Furthermore, this new model properly calibrated for the SMV wind farm is then used for coordinated control purposes. Assuming an axial induction control strategy, and following a model predictive approach, new power settings leading to an increased overall power production of the farm are derived. Power gains found are in the order of 2.5 % for a two wind turbine case with close spacing and 1 to 1.5 % for a row of five wind turbines with a larger spacing. Finally, the uncertainty of the updated Jensen model is quantified considering the model inputs. When checked against the predicted power gain, the uncertainty of the model estimations is seen to be excessive, reaching approximately 4 %, which indicates the difficulty of field observations for such a gain. Nevertheless, the optimized settings are to be implemented during a field test campaign at SMV wind farm in scope of the national project SMARTEOLE.

scholarly journals Development of new strategies for optimized structural monitoring of wind farms: description of the experimental field

2020 ◽  
Author(s):  
João Pacheco ◽  
Silvina Guimarães ◽  
Carlos Moutinho ◽  
Miguel Marques ◽  
José Carlos Matos ◽  
...  
Keyword(s):  
Wind Turbines ◽  
Wind Farm ◽  
Wind Farms ◽  
Structural Condition ◽  
Strain Gages ◽  
Onshore Wind ◽  
Experimental Campaign ◽  
Monitoring Strategies ◽  
Initial Results ◽  
New Strategies

Abstract. The main goal of the recently started WindFarmSHM research project is the development, validation and optimization of monitoring strategies to be applied at the level of the wind farm, which should be able to evaluate the structural condition of a set of wind turbines and their consumed fatigue life, using the response to operation loads. In this context, a quite extensive experimental campaign is being performed in Tocha wind farm, an onshore wind farm located in Portugal, which includes the simultaneous instrumentation of several wind turbines adoting strain gages, clinometers and accelerometers distributed in the tower and blades. This paper introduces the Tocha wind farm, presents the different layouts adopted in the instrumentation of the wind turbines and shows some initial results from the already fully instrumented wind turbine. At this preliminary stage, the capabilities of the very extensive monitoring layout will be demonstrated and it will be evaluated the ability of the different monitoring components to track the modal parameters of the system composed by tower and rotor.

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