Photovoltaic cells have been used for a long time to supply the electrical devices of small power in areas without access to the electricity networks (or other sources of electric energy). The ecological aspect of the use of the renewable energy sources, together with the technology development and increasingly lower costs of production the photovoltaic cells, cause the increase of their application. The solar power plants are built in several places in the world, not necessarily in the areas of high light intensity. Nowadays, such developments mostly depend on the wealth of a particular country. The largest photovoltaic power stations have power of a several dozen of MW. The major disadvantage of the photovoltaic cells is that the energy production is possible only during the day. This causes a necessity of energy accumulation in large photovoltaic systems. One possibility of storing large amounts of energy gives a hydrogen fuel, generated in the electrolysers powered directly from photovoltaic cells. Hydrogen, stored in pressure tanks or in tanks with synthetic porous materials, can be again used to produce electricity in fuel cells. This paper introduces selected issues and test results associated with the use of photovoltaic cells to power the hydrogen generators. The possible connections of photovoltaic modules integrated with electrolysers were analyzed. In this article the results of the electricity daily production by polycrystalline photovoltaic cells, collected in the course of the entire year were also presented.

The utilization of solar radiation to obtain high-temperature heat can be realized by multiplying it on the illuminated surface with solar concentrating technologies. High-temperature heat with significant energy potential can be used for many technological purposes, e.g. the production of heat, cold or electricity. The following paper presents the results of the experimental study, on the operation of the parabolic linear absorber in the parabolic concentrator solar system. The parabolic mirror with an aperture of 1 m and a focal length of 0.25 m focuses the simulated radiation onto a tubular absorber with a diameter of 33.7 mm, which is placed in a vacuum tube. The length of the absorber is 1 m. The installation is illuminated by the solar simulator, which allows to carry out tests under constant and repeatable conditions. The simulator consists of 18 metal halide lamps, with a nominal power of 575 W each with a dimming possibility of up to 60%. The paper presents preliminary results of heat absorption by the analysed absorber, temperature increment, collected heat flux, and the pressure drop crucial for the optimization of the absorber geometry.