This article reviews the most popular energy storage technologies and hybrid energy storage systems. With the dynamic development of the sector of renewable energy sources, it has become necessary to design and implement solutions that enable the maximum use of the energy obtained; for this purpose, an energy storage device is suggested. The most popular methods of electric energy storage are described, with an indication of the features of each technology, along with the presentation of the advantages and disadvantages of a given storage reservoir. Next, hybrid energy storage systems are presented along with their suggested applications and advantages resulting from the hybridization of technologically diverse energy storage systems.

This paper presents preliminary tests on a capacitively coupled wireless energy-transfer system (C-WET). Significant emphasis has been placed on discerning the fundamental characteristics of the system. This allowed the simulation model to be refined and the parameters of the physical prototype to be fine-tuned. Then, start-up tests of the prototype of the power supply system were presented, up to about 25% of the rated power. Selected simulation and laboratory test results are presented and directions for further work are set. The system is envisaged for underground mining applications, and the work is being carried out as part of the HEET II (High-Efficiency Energy Transfer) project, funded by the Research Fund for Coal and Steel (RFCS).