scholarly journals Feasibility study for 100 % renewable energy microgrids in Switzerland

2019 ◽  
Author(s):  
Sarah Barber ◽  
Simon Boller ◽  
Henrik Nordborg
Keyword(s):  
Renewable Energy ◽  
Wind Turbine ◽  
Feasibility Study ◽  
Wind Turbines ◽  
High Performance ◽  
Green Electricity ◽  
Capital Costs ◽  
Wind Speeds ◽  
Renewable Power ◽  
Cable Laying

Abstract. The growing worldwide level of renewable power generation requires innovative solutions to maintain grid reliability and stability, due to their variability and uncertainty. As well as stabilising the grid, renewable microgrids are also attractive solutions for regions wishing to produce green electricity independently from the grid, saving potentially high cable laying and grid connection costs. Switzerland does not yet have a large number of installed wind turbines, and despite the ambitious Energy Strategy 2050, not a single wind turbine was installed in 2018. This lack of progress is mainly due to large delays, costs and risks associated with the permitting procedure for wind turbines. The implementation of medium-sized wind turbines smaller than about 30 m may be a possible solution to this lack of progress, as they could experience an easier permitting procedure and higher acceptance among local residents. However, medium-sized wind turbines are less economically viable than larger wind turbines, and one method of making them more economically viable could be to combine them with photovoltaics (PV) and electricity storage into a renewable microgrid system. In this work, twelve sites in Switzerland are chosen for a 100 % renewable energy microgrid feasibility study. For all of these sites, a combination of wind and PV performs consistently better than wind only and PV only. This is due to the fact that wind speeds are often higher when the solar radiation is low, and vice versa. The combination of wind and PV ensures a more constant coverage of renewable energy production and therefore is more efficient. Five of the sites are found to be potentially economically viable, if investors would be prepared to make extra investments between 0.05 $/kWh and 0.2 $/kWh or between $5 million and $20 million upfront for green electricity independence. The Self-Sufficiency Ratio (SSR) is found to range between 1 and 2 for each site, reflecting the extra installed capacity required in order to fully cover every hour of demand in island operation. This could be decreased by connecting to the grid at times of low wind and solar resource and high demand. For the Wind and PV combination, halving battery capital costs reduces Costs of Electricity (COE) by 11 %, decreases the number of wind turbines by 1 % and reduces SSR by 1 %. Halving the wind turbine capital costs reduces COE by 30 %, increases the number of wind turbines by 16 % and increases the SSR by 16 %. Reducing the PV capital costs by 50 % reduces COE by 8 %, decreases the number of wind turbines by 39 % and decreases the SSR by 19 %. The actual implementation of 100 % renewable energy microgrids with medium-sized wind turbines is found to be strongly limited by the area required by the wind turbines as well as by the total number of wind turbines that can be realistically implemented. Additionally, a case study for an extension to a High Performance Computing centre in Canton Glarus shows that a feasible solution is available that meets the requirements. Specific projects are being further examined on a case-to-case basis.

scholarly journals Potential of Shrouded Micro Wind Turbine

2017 ◽  
Vol 7 (2 (S)) ◽  
pp. 340
Author(s):  
Kishor Sontakke ◽  
Samir Deshmukh ◽  
Sandip Patil
Keyword(s):  
Renewable Energy ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Renewable Energy Sources ◽  
Turbine Blades ◽  
Weather Conditions ◽  
Power Coefficient ◽  
Solar Panels ◽  
Wind Speeds ◽  
Low Wind Speeds

The growing demand for electrical energy for industrial and domestic use, coupled with the limited amount of available fossil fuel reserves and its negative effects on the environment, have made it necessary to seek alternative and renewable energy sources. The use of renewable energy is promoted worldwide to be less dependent on conventional fuels and nuclear energy. Therefore research in the field is motivated to increase efficiency of renewable energy systems. This study aimed to study potential of micro wind turbine and velocity profile through shroud for low wind speeds. Although there is a greater inclination to use solar panels because of the local weather conditions, there are some practical implications that have place the use of solar panels in certain areas to an end. The biggest problem is panel stealing. Also, in some parts of the country the weather is more appropriate to apply wind turbines. Thus, this study paying attention on the design of a new concept to improve wind turbines to be appropriate for the low wind speeds in India. The concept involves the implementation of a concentrator and diffuser to a wind turbine, to increase the power coefficient. Although the wind turbine was not tested for starting speeds, the realization of the shroud should contribute to improved starting of the wind turbine at lower wind speeds. The configuration were not manufactured, but simulated with the use of a program to obtain the power production of the wind turbine over a range of wind speeds. These values were compared to measured results of an open wind turbine developed. The most important topic at hand when dealing with a shrouded wind turbine is to find out if the overall diameter or the blade diameter of the turbine should be the point of reference. As the wind turbine is situated in a shroud that has a larger diameter than the turbine blades, some researchers believe that the overall diameter should be used to calculate the efficiency. The benefits of shrouded wind turbines are discussed.

EXPERIMENTAL AND ANALYTICAL STUDIES OF VERTICAL AXIS WIND TURBINES

2018 ◽  
pp. 51-58
Author(s):  
B. P. Khozyainov
Keyword(s):  
Wind Turbine ◽  
Flow Velocity ◽  
Wind Power ◽  
Wind Turbines ◽  
Power Efficiency ◽  
Air Flow ◽  
Geometrical Parameters ◽  
Wind Speeds ◽  
Analytical Studies ◽  
Air Flow Velocity

The article carries out the experimental and analytical studies of three-blade wind power installation and gives the technique for measurements of angular rate of wind turbine rotation depending on the wind speeds, the rotating moment and its power. We have made the comparison of the calculation results according to the formulas offered with the indicators of the wind turbine tests executed in natural conditions. The tests were carried out at wind speeds from 0.709 m/s to 6.427 m/s. The wind power efficiency (WPE) for ideal traditional installation is known to be 0.45. According to the analytical calculations, wind power efficiency of the wind turbine with 3-bladed and 6 wind guide screens at wind speedsfrom 0.709 to 6.427 is equal to 0.317, and in the range of speed from 0.709 to 4.5 m/s – 0.351, but the experimental coefficient is much higher. The analysis of WPE variations shows that the work with the wind guide screens at insignificant average air flow velocity during the set period of time appears to be more effective, than the work without them. If the air flow velocity increases, the wind power efficiency gradually decreases. Such a good fit between experimental data and analytical calculations is confirmed by comparison of F-test design criterion with its tabular values. In the design of wind turbines, it allows determining the wind turbine power, setting the geometrical parameters and mass of all details for their efficient performance.

SHAPING OF AN AUTONOMOUS POWER SYSTEM FOR GUARANTEED POWER SUPPLY WITH THE PREDOMINANCE WIND ENERGY

2018 ◽  
pp. 28-50
Author(s):  
S. G. Ignatiev ◽  
S. V. Kiseleva
Keyword(s):  
Energy Storage ◽  
Wind Speed ◽  
Wind Energy ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Energy Demand ◽  
Diesel Generator ◽  
Average Wind Speed ◽  
Wind Speeds ◽  
Average Wind

Optimization of the autonomous wind-diesel plants composition and of their power for guaranteed energy supply, despite the long history of research, the diversity of approaches and methods, is an urgent problem. In this paper, a detailed analysis of the wind energy characteristics is proposed to shape an autonomous power system for a guaranteed power supply with predominance wind energy. The analysis was carried out on the basis of wind speed measurements in the south of the European part of Russia during 8 months at different heights with a discreteness of 10 minutes. As a result, we have obtained a sequence of average daily wind speeds and the sequences constructed by arbitrary variations in the distribution of average daily wind speeds in this interval. These sequences have been used to calculate energy balances in systems (wind turbines + diesel generator + consumer with constant and limited daily energy demand) and (wind turbines + diesel generator + consumer with constant and limited daily energy demand + energy storage). In order to maximize the use of wind energy, the wind turbine integrally for the period in question is assumed to produce the required amount of energy. For the generality of consideration, we have introduced the relative values of the required energy, relative energy produced by the wind turbine and the diesel generator and relative storage capacity by normalizing them to the swept area of the wind wheel. The paper shows the effect of the average wind speed over the period on the energy characteristics of the system (wind turbine + diesel generator + consumer). It was found that the wind turbine energy produced, wind turbine energy used by the consumer, fuel consumption, and fuel economy depend (close to cubic dependence) upon the specified average wind speed. It was found that, for the same system with a limited amount of required energy and high average wind speed over the period, the wind turbines with lower generator power and smaller wind wheel radius use wind energy more efficiently than the wind turbines with higher generator power and larger wind wheel radius at less average wind speed. For the system (wind turbine + diesel generator + energy storage + consumer) with increasing average speed for a given amount of energy required, which in general is covered by the energy production of wind turbines for the period, the maximum size capacity of the storage device decreases. With decreasing the energy storage capacity, the influence of the random nature of the change in wind speed decreases, and at some values of the relative capacity, it can be neglected.

scholarly journals Holistic simulation of wind turbines with fully aero-elastic and electrical model

2021 ◽  
Author(s):  
Marcus Wiens ◽  
Sebastian Frahm ◽  
Philipp Thomas ◽  
Shoaib Kahn
Keyword(s):  
Renewable Energy ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Low Voltage ◽  
Renewable Energy Sources ◽  
Elastic Model ◽  
Electrical Model ◽  
Holistic Model ◽  
Electric System ◽  
Electrical Components

AbstractRequirements for the design of wind turbines advance facing the challenges of a high content of renewable energy sources in the public grid. A high percentage of renewable energy weaken the grid and grid faults become more likely, which add additional loads on the wind turbine. Load calculations with aero-elastic models are standard for the design of wind turbines. Components of the electric system are usually roughly modeled in aero-elastic models and therefore the effect of detailed electrical models on the load calculations is unclear. A holistic wind turbine model is obtained, by combining an aero-elastic model and detailed electrical model into one co-simulation. The holistic model, representing a DFIG turbine is compared to a standard aero-elastic model for load calculations. It is shown that a detailed modelling of the electrical components e.g., generator, converter, and grid, have an influence on the results of load calculations. An analysis of low-voltage-ride-trough events during turbulent wind shows massive increase of loads on the drive train and effects the tower loads. Furthermore, the presented holistic model could be used to investigate different control approaches on the wind turbine dynamics and loads. This approach is applicable to the modelling of a holistic wind park to investigate interaction on the electrical level and simultaneously evaluate the loads on the wind turbine.

scholarly journals Effect of Wind Turbine Classes on the Electricity Production of Wind Farms in Cyprus Island

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Yiannis A. Katsigiannis ◽  
George S. Stavrakakis ◽  
Christodoulos Pharconides
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Energy Production ◽  
Wind Farms ◽  
Electricity Production ◽  
Wind Speeds ◽  
Wind Potential

This paper examines the effect of different wind turbine classes on the electricity production of wind farms in two areas of Cyprus Island, which present low and medium wind potentials: Xylofagou and Limassol. Wind turbine classes determine the suitability of installing a wind turbine in a particulate site. Wind turbine data from five different manufacturers have been used. For each manufacturer, two wind turbines with identical rated power (in the range of 1.5 MW–3 MW) and different wind turbine classes (IEC II and IEC III) are compared. The results show the superiority of wind turbines that are designed for lower wind speeds (IEC III class) in both locations, in terms of energy production. This improvement is higher for the location with the lower wind potential and starts from 7%, while it can reach more than 50%.

Wind Turbine Aerodynamic Braking System Analysis Using Chord Wise Spacing

2015 ◽  
Vol 787 ◽  
pp. 217-221 ◽  
Author(s):  
B. Navin Kumar ◽  
K.M. Parammasivam
Keyword(s):  
Renewable Energy ◽  
Wind Turbine ◽  
Wind Velocity ◽  
Turbine Blade ◽  
Wind Turbines ◽  
Renewable Energy Sources ◽  
Energy Resource ◽  
Braking System ◽  
Extreme Wind ◽  
Wind Potential

Wind energy is one of the most significant renewable energy sources in the world. It is the only promising renewable energy resource that only can satisfy the nation’s energy requirements over the growing demand for electricity. Wind turbines have been installed all over the wind potential areas to generate electricity. The wind turbines are designed to operate at a rated wind velocity. When the wind turbines are exposed to extreme wind velocities such as storm or hurricane, the wind turbine rotates at a higher speed that affects the structural stability of the entire system and may topple the system. Mechanical braking systems and Aerodynamic braking systems have been currently used to control the over speeding of the wind turbine at extreme wind velocity. As a novel approach, it is attempted to control the over speeding of the wind turbine by aerodynamic braking system by providing the chord wise spacing (opening). The turbine blade with chord wise spacing alters the pressure distribution over the turbine blade that brings down the rotational speed of the wind turbine within the allowable limit. In this approach, the over speeding of the wind turbine blades are effectively controlled without affecting the power production. In this paper the different parameters of the chord wise spacing such as position of the spacing, shape of the spacing, width of the spacing and impact on power generation are analyzed and the spacing parameters are experimentally optimized.

Simulation of Flow Field on a Large Scale Wind Turbine

2008 ◽  
Author(s):  
I. Janajreh ◽  
C. Ghenai
Keyword(s):  
Flow Field ◽  
Wind Energy ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Cross Sections ◽  
Large Scale ◽  
Wind Farms ◽  
Operating Characteristics ◽  
Cross Sectional ◽  
Capital Costs

Large scale wind turbines and wind farms continue to evolve mounting 94.1GW of the electrical grid capacity in 2007 and expected to reach 160.0GW in 2010 according to World Wind Energy Association. They commence to play a vital role in the quest for renewable and sustainable energy. They are impressive structures of human responsiveness to, and awareness of, the depleting fossil fuel resources. Early generation wind turbines (windmills) were used as kinetic energy transformers and today generate 1/5 of the Denmark’s electricity and planned to double the current German grid capacity by reaching 12.5% by year 2010. Wind energy is plentiful (72 TW is estimated to be commercially viable) and clean while their intensive capital costs and maintenance fees still bar their widespread deployment in the developing world. Additionally, there are technological challenges in the rotor operating characteristics, fatigue load, and noise in meeting reliability and safety standards. Newer inventions, e.g., downstream wind turbines and flapping rotor blades, are sought to absorb a larger portion of the cost attributable to unrestrained lower cost yaw mechanisms, reduction in the moving parts, and noise reduction thereby reducing maintenance. In this work, numerical analysis of the downstream wind turbine blade is conducted. In particular, the interaction between the tower and the rotor passage is investigated. Circular cross sectional tower and aerofoil shapes are considered in a staggered configuration and under cross-stream motion. The resulting blade static pressure and aerodynamic forces are investigated at different incident wind angles and wind speeds. Comparison of the flow field results against the conventional upstream wind turbine is also conducted. The wind flow is considered to be transient, incompressible, viscous Navier-Stokes and turbulent. The k-ε model is utilized as the turbulence closure. The passage of the rotor blade is governed by ALE and is represented numerically as a sliding mesh against the upstream fixed tower domain. Both the blade and tower cross sections are padded with a boundary layer mesh to accurately capture the viscous forces while several levels of refinement were implemented throughout the domain to assess and avoid the mesh dependence.

scholarly journals Pengaruh diameter dan jumlah sudu turbin angin savonius tipe L terhadap unjuk kerja yang dihasilkan

2020 ◽  
Vol 1 (2) ◽  
pp. 61-67
Author(s):  
Mohammad Rizqi Saputra ◽  
Nur Kholis ◽  
Mohammad Munib Rosadi
Keyword(s):  
Energy Source ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Mechanical Energy ◽  
Simulation Method ◽  
Wind Speeds ◽  
Turbine Efficiency ◽  
Analysis Technique ◽  
Low Wind Speeds ◽  
Wind Source

Abstract Wind is a renewable mechanical energy source that can be used as an energy source because the energy from the wind can be used to drive wind turbines. Savonius wind turbine type L is a tool to convert wind energy into electricity with a simple construction and can work with low wind speeds. The purpose of this study was to determine the effect of differences in diameter and number of blades on the power produced. The method used is a simulation method with an artificial wind source. With a wind speed of 8 m/s. The data analysis technique used is 2-way ANOVA using the SPSS application. Variations used are 20 cm and 40 cm in diameter and the number of blades 2 and 4 . The result is a wind turbine with a variation of 40 cm and 4 blades capable of producing the best output which produces 350.98 RPM voltage of 11.64 volts current of 0.144 amperes and power of 1,676 watts. As for BHP, torque, and turbine efficiency with a variation of 40 cm and 4 blades capable of producing the best output where the generated BHP is 3.352 watts, torque 0.091 N / m efficiency 2.17. For the results of calculations with SPSS wind turbines with a diameter variation of 40 cm and 4 blades, the biggest power is 1,744 watts and for BHP produces 3.3520 watts and the efficiency reaches 2.17%. Keyword : Diameter, number of blade, Performance Abstrak Angin adalah sumber energi mekanik yang bisa diperbaharui sehingga dapat dimanfaatkan sebagai sumber energi karena dapat digunakan untuk menggerakkan turbin angin. Turbin angin savonius tipe L merupakan alat untuk mengubah energi angin menjadi listrik dengan konstruksi yang sederhana dan dapat bekerja dengan kecepatan angin yang rendah. Tujuan penelitian ini untuk mengetahui pengaruh perbedaan diameter dan jumlah sudu terhadap unjuk kerja yang dihasilkan. Metode yang digunakan adalah metode simulasi dengan sumber angin buatan. Dengan kecepatan angin 8 m/s. Teknik analisis data yang digunakan adalah ANOVA 2 arah dengan menggunakan aplikasi SPSS. Variasi yang digunakan adalah diameter 20 cm dan 40 cm serta jumlah sudu 2 dan 4. Hasilnya turbin angin dengan variasi 40 cm dan 4 sudu mampu menghasilkan output terbaik yang dimana menghasilkan RPM 350,98 tegangan 11,64 volt arus 0,144 ampere dan daya 1,676 watt. Sedangkan untuk BHP, torsi, dan efisensi turbin dengan variasi 40 cm dan 4 sudu mampu menghasilkan output yang terbaik dimana BHP yang dihasilkan adalah 3,352 watt, torsi 0,091 N/m efisisensi 2,17. Untuk hasil perhitungan dengan SPSS turbin angin dengan variasi diameter 40 cm dan 4 sudu menghasilkan daya terbesar yakni 1,744 watt dan untuk BHP menghasilkan 3,3520 watt dan efisiensinya mencapai 2,17 % untuk torsi tertinggi dicapai turbin variasi 40 cm 2 sudu dengan torsi 0,116.   Kata kunci : diameter, jumlah sudu, unjuk kerja

Effect of Slotted Angle on Savonius Wind Turbine Performance

2021 ◽  
Vol 104 ◽  
pp. 83-88
Author(s):  
Rahmat Wahyudi ◽  
Diniar Mungil Kurniawati ◽  
Alfian Djafar
Keyword(s):  
Wind Energy ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Electrical Energy ◽  
Speed Ratio ◽  
Angle Variation ◽  
Wind Speeds ◽  
Turbine Performance ◽  
Savonius Wind Turbine ◽  
Low Wind Speeds

The potential of wind energy is very abundant but its utilization is still low. The effort to utilize wind energy is to utilize wind energy into electrical energy using wind turbines. Savonius wind turbines have a very simple shape and construction, are inexpensive, and can be used at low wind speeds. This research aims to determine the effect of the slot angle on the slotted blades configuration on the performance produced by Savonius wind turbines. Slot angle variations used are 5o ,10o , and 15o with slotted blades 30% at wind speeds of 2,23 m/s to 4,7 m/s using wind tunnel. The result showed that a small slot angle variation of 5o produced better wind turbine performance compared to a standard blade at low wind speeds and a low tip speed ratio.

scholarly journals Analysis of the Patent of a Protective Cover for Vertical-Axis Wind Turbines (VAWTs): Simulations of Wind Flow

2020 ◽  
Vol 12 (18) ◽  
pp. 7818
Author(s):  
Jose Alberto Moleón Baca ◽  
Antonio Jesús Expósito González ◽  
Candido Gutiérrez Montes
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Wind Turbines ◽  
High Speed ◽  
Experimental Tests ◽  
Weather Conditions ◽  
Vertical Axis ◽  
Good Alternative ◽  
Wind Speeds ◽  
Vertical Axis Wind Turbines

This paper presents a numerical and experimental analysis of the patent of a device to be used in vertical-axis wind turbines (VAWTs) under extreme wind conditions. The device consists of two hemispheres interconnected by a set of conveniently implemented variable section ducts through which the wind circulates to the blades. Furthermore, the design of the cross-section of the ducts allows the control of the wind speed inside the device. These ducts are intended to work as diffusers or nozzles, depending on the needs of the installation site. Simulations were performed for the case of high-speed external wind, for which the ducts act as diffusers to reduce wind speed and maintain a well-functioning internal turbine. Four different patent designs were analyzed, focusing on turbine performance and generated power. The results indicate that the patent allows the generation of electric power for a greater range of wind speeds than with a normal wind turbine. The results support that this patent may be a good alternative for wind power generation in geographic areas with extreme weather conditions or with maintained or strong gusty wind. Experimental tests were carried out on the movement of the blades using the available model. Finally, the power curve of the model of this wind turbine was obtained.

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