For several years, research work has been carried out on energy storage that uses changes in the potential energy of masses being lifted or lowered. The energy of such a solution depends on the mass to be transported and the height to which the weight has to be lifted. Increasing the weight to be lifted is limited by the parameters of the mechanical components, such as ropes. Increasing the height, however, is difficult to implement, if only because of the weather conditions that affect the safe operation of such a system. In fact, the ideal solution is to use mine shafts, which in Poland are up to 1300 m deep. The progressive process of decommissioning the mining industry creates new opportunities to use this part of the infrastructure of mining plants for the construction of energy storage facilities. In the article, possible constructions of gravitational energy storage facilities based on existing hoisting machines are described. There are three main areas in which the operation of an energy store should be analysed if it were to be realised in a mine shaft. The mine shaft, as a working mine and for energy storage, is subject to relevant regulations that need to be met. To confirm the assumptions about the possible use of the existing infrastructure, measurements of one hoisting machine in Poland were carried out and example results of these measurements are included.

There are currently more than 30 underground mines operating in Poland. These are mines extracting hard coal, salt, and metal ores. Each of these plants has its own specifics for operation, but all operate under the same regulations. The basic principle is to ensure the safety of the crew and equipment. The progressive mechanization and automation of the mining process results in the installation of power electronic converters in the networks of mining plants, which significantly deteriorate the quality of the power in the plant supply networks. In addition, the constant reconfiguration of these networks related to the progress of the work can affect the safety conditions of the plant. This article describes problems occurring at one underground mining plant that are related to the structure of the power grid. Failures and interruptions in the production process were the result of poor power quality. They directly translated into increased production costs and significantly affected the safety level of the workforce, which could result in further consequences, not only in the financial sphere. The article also addresses the issue of existing legal regulations, the provisions of which may be insufficient in assessing the current state of power quality in mining plants.

Storage of energy is one of the main problem of contemporary technology. Currently used manners of the energy store are listed below: (1) the magnetic accumulator - the energy is kept in the magnetic field of superconductive inductor, (2) the accumulator with super capacitors. The low voltage (1,6-2,5 V) is the fault of this one,(3) the accumulator with lead-acid or alkaline accumulator. The fault of this solution is very low charging and discharging efficiency, (4) the electromechanical accumulator. Flywheels store energy mechanically in the form of kinetic energy. In this article the flywheel energy storage will be described precisely and compared with other energy storage technologies.

Wydawnictwo SIGMA-NOT wydaje czasopisma fachowe informujące swoich czytelników o najnowszych osiągnięciach naukowych i nowoczesnych rozwiązaniach technicznych w Polsce i na świecie, popularyzuje problemy techniczne oraz poszerza wiedzę i kulturę techniczną.

The paper presents an experimental investigation of a flywheel energy storage system. The device is based on a flywheel concept and stores mechanical energy. This device contains a brushless DC motor supplied by an electronic commutator. A steel barrel performs the function of the flywheel. From the power network side this device is perceived as a resistive load. This is achieved owing to the use of the rectifier with sinusoidal source current.

In this article the storage systems: capacitors, batteries and flywheel energy storage are described. The flywheel energy storage will be described precisely and compared with other energy storage technologies.