Investigation of Wind Energy Distribution in Height in Latvia

Abstract

In the National Development Plan of Latvia for the time 2014 – 2020 a significant role is assigned to the renewable energy, whose share in the total energy production should be 40 %. This will facilitate the efficient use of wind energy. The paper is devoted to the investigation into the wind energy potential based on long-term observations of the wind speed and energy density fluctuations at heights from 10 to 160 m in the Latvian territory and on the coast of Baltic Sea.The wind speed and wind direction values were measured and the statistical database has been accumulated during long-term observations in 2004 – 2013 using a LOGGER 9200 Symphonie measuring systems mounted on 60 m masts – one on the western coast and the second on the north-east of Latvia. From June 2011 to May 2012, these measurements were complemented with the data for the heights from 40 to 160 m obtained by means of a ZephIR lidar located on the western coast of Latvia and with the metrological data provided by “Latvian Environment, Geology and Meteorology Centre” for the same period. The results are presented in the form of tables, bar charts and graphs. The graphs of seasonal fluctuations in the wind speed have been obtained for the heights up to 160 m by measurements over the period of 2007 – 2013. The histograms are composed for the relative frequency of repetition of the wind speed. The wind speed distribution on heights up to 200 m are analysed and the coefficients of approximating functions for two areas with different terrain types are calculated. Extrapolation results of the distribution curves of wind velocity and density mean values on heights up to 200 m are presented. The results of the research on the wind speed distribution up to 200 m are promising for evaluation of the wind energy potential in Latvia and should help in assessment of prospective sites for construction of WPPs.