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The article discusses some aspects of the use of renewable energy sources in the climatic conditions prevailing in most of the territory of Latvia, with relatively low wind speeds and a small number of sunny days a year. The paper gives a brief description of the measurement equipment and technology to determine the parameters of the outer air; the results of the measurements are also analysed. On the basis of the data obtained during the last two years at the meteorological station at the Botanical Garden of the University of Latvia, the energy potential of solar radiation and wind was estimated. The values of the possible and the actual amount of produced energy were determined.

Under the conditions of continuous increase in the energy consumption, sharply rising prices of basic energy products (gas, oil, coal), deterioration of environment, etc., it is of vital importance to develop methods and techniques for heat and power generation from renewables. The paper considers the possibility to use a sail-type wind turbine for autonomous power supply in Latvia, taking into account its climatic conditions. The authors discuss the problems of developing a turbine of the type that would operate efficiently at low winds, being primarily designed to supply power to small buildings and farms distant from centralized electricity networks. The authors consider aerodynamic characteristics of such a turbine and the dependence of the thrust moment of its pilot model on the airflow rate at different angles of attack. The pilot model with a changeable blade shape has been tested and shows a good performance.

Physical features of an electric discharge in a gas-liquid medium are investigated; a direct relationship between the entropy change and the fractal nature of the medium itself is shown. Simplified equations and laws of conservation that describe the dynamics of the electric discharge in the two-phase liquid with allowance for the thermodynamic properties of the medium as functions of its fractal structure are used.

A new theoretical description is proposed for complicated nonlinear phenomena accompanying the electrohydraulic effect in a two-phase medium. The polytrope parameter is related to the fractal properties of the medium, which themselves are related to the gas content.

The paper discusses problems of energy supply of buildings using renewable sources given the local climatic conditions. The meteorological conditions in Latvia and Riga for last year were analyzed. In paper shows examples of energy efficient buildings allowing that to provide comfort temperature and indoor air quality. The structure and composition of local building materials, providing good thermal insulation are described. The heating systems for test buildings using renewable energy sources were investigated. The assessment of the energy efficiency of the “air-air” and “air-water” heat pumps is studied.