Tag Archives: wind energy

1720-1729 T. Vaimann, A. Rassõlkin, A. Kallaste and M. Märss
Feasibility study of a local power supply system for sparsely populated areas in Estonia
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Feasibility study of a local power supply system for sparsely populated areas in Estonia

T. Vaimann¹²*, A. Rassõlkin¹, A. Kallaste¹² and M. Märss¹³

¹Tallinn University of Technology, Faculty of Power Engineering, Department of Electrical Engineering, Ehitajate tee 5, EE19086 Tallinn, Estonia
²Aalto University, School of Electrical Engineering, Department of Electrical Engineering and Automation, PO Box 13000, FI00076 Aalto, Finland
³Estonian University of Life Sciences, Institute of Technology, Department of Energy Engineering, Fr.R. Kreutzwaldi 56/1, EE51014 Tartu, Estonia
*Correspondence: toomas.vaimann@ttu.ee

Abstract:

The paper analyzes the reasonability of using an off-grid hybrid power supply system or in other words a local grid for sparsely populated areas as well as the necessary components selection and price development of such system. Typical consumers are selected and all estimations and calculations are based on them. Consumer profiles are set and analyzed as well as different elements of the local power supply grid and the possibility of connecting to the traditional grid. Estonian example is used in this paper as the country lies relatively north and has some remote areas, where local power supply grids can be implemented. All prices in the paper are derived from the Estonian example. Necessity of further study is proposed.

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226-235 V. Põder, T. Peets, K. Toom and A. Annuk
The Estimation of Wind Lull and Consumption Factor Influence on Autonomous Wind Energy System
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The Estimation of Wind Lull and Consumption Factor Influence on Autonomous Wind Energy System

V. Põder, T. Peets, K. Toom and A. Annuk

Department of Energy Application, Institute of Technology,
Estonian University of Life Sciences, 56 Kreutzwaldi Str., EE51014 Tartu, Estonia
e-mail: vahur.poder@emu.ee

Abstract:

Due to the stochastic output of wind generators, some kind of storage device will be necessary to ensure a constant energy supply by an autonomous energy system. The necessary storage capacity depends on wind data and consumption factor. The latter describes the ratio between average production capacity and average usage capacity. In addition to average wind speed, the frequency and duration of windless periods must be considered as well. The concept of energy lulls has been outlined to describe the influence of duration, frequency and distribution of wind less periods on a wind energy system. Location has strong influence on energy lull length; the difference in average duration between a coastal area and inland is more than two fold. Weibull distribution can be used to describe the probability of energy lulls.

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169-179 A. Annuk, E. Kokin, V. Palge, V. Põder and J. Lepa
Wind energy application problems in inland Estonia
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Wind energy application problems in inland Estonia

A. Annuk, E. Kokin, V. Palge, V. Põder and J. Lepa

Department of Energy Application, Institute of Technology,Estonian University of Life Sciences, Kreutzwaldi 56, 51014, Tartu;e-mail: andres.annuk@emu.ee

Abstract:

The inland regions of Estonia have not been seen as suitable economically for de-ployment of wind energy systems. Prices for technological development of wind turbines are going down, while energy prices are rising constantly. Since rural regions of Estonia are under-populated, the use of small scale wind turbine generators in these conditions is becoming more promising. Average wind speeds in mainland Estonia are 2.5–3.5 m s-1. Only a very small part of the wind speed frequency distribution (~4 ppm) exceeds 12 m s-1. More suitable for these regions are wind turbine generators which switch on at wind speeds less than 3 m s-1 and reach nominal output power at 11–12 m s-1. They have similar-looking power curves, so it is possible to model the first rising part of the curve up to maximal power by second order polynomial. Because the wind speed rarely exceeds 12 m s-1 in inland regions there is no need to model the whole power curve. The average power curve makes it possible to estimate an approximate en-ergy production of small scale wind turbine generators in a given region if the wind speed fre-quency distribution is known.

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