The Study of Wind Energy Resource and the Assessment of the Economic Feasibility of Wind Energy Projects
Summary of the Doctoral Thesis
Deniss Bezrukovs, Riga Technical University, Latvia
The purpose of the work is to reduce the cost of wind energy production and increase the feasibility of wind power projects. The author considers methods for predicting operational efficiency of WT and revenue streams generated by wind energy projects using stochastic differential equation models. The study develops wind shear assessment methods based on the analysis of the results of long-term wind speed measurements. Furthermore, the study presents density maps of long-term average wind speed and wind energy distribution on the territory of Latvia at the height of 10 m based on the results of wind speed measurements obtained from LEGMC for the period 2015 – 2016. Along with wind shear estimation, the possibility of using the power law function to extrapolate the values of the parameters of the Weibull distribution to the height corresponding to the location of the wind turbine axis is investigated. In order to evaluate the possibility of using the network of communication masts for wind speed measurements, the effect of lattice mast structure on the results of wind speed measurements using CFD modelling and experimental results is performed. It is shown that the recommendations of IEC 61400-12-1 technical standard regarding the placement of sensors on the lattice mast do not allow conducting wind speed measurement with the required level of precision. A method for improving the accuracy of wind speed measurements using lattice masts is proposed by comparing the estimation results of two sensors installed at the same height and displaced by an angle of at least 120о. The density maps of Weibull distribution parameters for average values of wind speed at the height of 10 m for the territory of Latvia are provided. These maps serve as a reference tool for assessing wind energy resource potential at any location in Latvia at a height of 10 m and estimating operational efficiency of low-power wind generators for WTs with vertical and horizontal axes. In order to demonstrate the practical applicability of the approach, the model of the spatial distribution of relative capacity factor for horizontal axes WT with rated power 2.5 kW at the height of 10 m above the ground is developed. Finally, the study investigates variations in the operational efficiency of WT in the conditions of low winds depending on the height of the mast and generator type, as well as provides suggestions with respect to the optimal choice of wind generator type for Latvian weather conditions.
|Country of Publication