For the development of the energy infrastructure of remote isolated consumers, an expedient solution is the creation of modular hybrid energy system based on the renewable energy sources, which will save tens of billions of rubles a year by saving expensive diesel fuel. Taking into account the high wind energy resource in these territories, the use of wind power plants as part of that system is justified. The article discusses the methodology for substantiating the parameters and modes of operation of an autonomous wind-diesel power complex based on the territorial-power classification of power supply systems and a 4-level methodology for optimizing parameters, an example of upgrading an existing diesel power plant (DPP) in the Arkhangelsk region is given. The existing DPP with a capacity of 1300 kW was replaced by a modular wind-diesel power system with a high renewable penetration level (58%) with four wind turbines with a capacity of 200 kW and a storage system with a capacity of 65 kWh. This made it possible to achieve a diesel fuel replacement share of 232,000 liters. per year, which in monetary terms in 2021 prices is 25 million rubles per year. As a promising direction, a variant of the territorial development of the energy sector of the Leshukonsky district of the Arkhangelsk region based on wind energy with the possibility of producing up to 100 tons of "green" hydrogen annually is considered. Various options for reducing harmful emissions in the region were considered, the maximum use of local resources allows saving up to 22,000 tons of CO2e per year

Over the past few years, much attention has been paid to hydrogen energy. The development of hydrogen technologies leads to a reduction in the cost of both the hydrogen fuel itself and hydrogen systems, which leads to a wider use of this type of fuel in various branches of the fuel and energy complex.
At the moment, the primary task is to increase the efficiency of combined cycle power units, reduce wear and tear of equipment during peak electricity consumption, reliable backup of energy supply, and reduce harmful emissions during the generation of heat and electricity. One of the modern methods for implementing these challenges is the use of energy storage devices. A new solution to this problem can be the introduction of hydrogen storage in the cycle of a thermal power plant.
The article considers the modernization of a combined-cycle power unit with a gas turbine PG6111FA manufactured by «General Electric» with a rated power of 80 MW, a waste heat steam boiler manufactured by JSC «EnergoMashinostroitelny » Alliance, and a steam turbine KT-33/36-7.5/0.12. During periods of night unloading, the effective efficiency of the power unit drops, so it is necessary not to unload the equipment, but to turn on the electrolyzers for the production of hydrogen fuel for further use in hydrogen fuel cells. The operating time of the hydrogen system with an electrolyzer is not limited in time, the operation of the electrolyzer takes place during night unloading periods (from 4 to 7 hours a day), while the hydrogen storage works constantly, in this mode of operation, the service life is about 15 years, for stable operation it is necessary hydrogen fuel and periodic maintenance. An important component of the hydrogen system is a hydrogen battery with minimal storage losses, in contrast to traditionally installed thermal storage. Studies of the use of hydrogen storage in the circuits of thermal power plants have shown their effectiveness, including their implementation allows you to increase the efficiency, reduce the cost of own needs of the power plant, reduce emissions in the production of electricity, a leveled load schedule allows you to increase the life of the gas turbine, as the turbine works in basic mode. The use of accumulators in thermal power plants increases the competitiveness among traditional energy generation systems.

Preliminary calculations suggest that 530 million tons of hydrogen can be obtained from the utilization of heat from blast-furnace and converter processes in the global steel production, which is approximately 8 times higher than the current annual production of hydrogen (75 million tons).
Mankind, already now, by introducing everywhere the technology of utilizing the heat of cooling steel for the pyrolysis of methane, can achieve an 8-fold excess of world hydrogen production.
To date, the use of heat from metallurgical processes (steel) for methane pyrolysis using all available possibilities for the maximum high-quality and relatively cheap separation of methane into soot and hydrogen is an important tactical task.In the process of globally organized petrochemical production of hydrogen by cracking methane in the steelmaking process, it is possible to arrange the production of high-purity hydrogen and high-purity carbon for further synthesis of tubulenes, graphene-like and fullerene-like materials. However, the following tasks stand in the way of this problem: 1) careful study of the behavior of saturated hydrocarbons, including methane at near-critical parameters and supercritical parameters, 2) organization of the optimal process for removing soot (carbon) from a catalytic cracking processor, 3) profiling the optimal design of catalytic cracking – processor.

One of the key targets contributing to the implementation of the goal of developing the energy sector of the Russian Federation and listed in the Energy Strategy of the Russian Federation for the period up to 2035 is reduction of the negative impact of the fuel and energy complex on the environment.
In this regard, the coal ash handling problem is given special attention, which is increased by the tightening of environmental legislation with the transition to the principles of the best available technologies, the greening of coal energy, the exhaustion of the ash and slag disposal sites, etc. Utilization of the ash, slag, as well as the ash and slag mixtures produced from combustion of coal, peat and oil shale, is one of the main problems of the modern Russian solid-fuel thermal power plants, numbering 172 ones in our country. The average age of the coal-fired thermal power plants is about 50 years, which significantly affects the technical and environmental performance of the TPP ash removal systems. At the Russian TPPs, the ash and slag is mostly conveyed using hydraulic ash and slag removal systems, being technically obsolete, uneconomical and environmentally unfriendly.
Annually in the Russian Federation 25…30 million tons of coal ash are produced. Currently, more than 1.5 billion tons of coal ash have been accumulated at the ash and slag disposal sites of thermal power plants; and these figures are growing every year. About 2/3 of all ash and slag disposal sites are close to their design filling or are already full. Elimination of the facilities (the ash and slag disposal sites) representing the accumulated environmental damage is one of the conditions for Russia's transition to the standards of a "green" economy. The problem of coal-fired thermal power plants in terms of eliminating the accumulated environmental damage can only be solved through the implementation of the large-scale projects of the integrated processing of the coal ash in order to obtain demanded products.
The article provides statistical data on the volumes of production and utilization of the coal ash in different countries of the world community in 2019. It presents an overview of the various applications of the coal combustion byproducts in Russia, the U.S., India, China, and the EU countries. The article contains data on the applicability of the coal ash for various technologies for their use according to the data of the Ministry of Energy of the Russian Federation. The paper contains a review of different sources of scientific and technical information on the prospects for the use of the coal ash in hydrogen energy industry for the sorption and storage of hydrogen, as well as a review of traditional hydrogen storage methods. The terminology in the field of coal combustion by-products handling, found in scientific and technical sources of information, is considered, and the classification of the coal combustion byproducts in Russia and abroad is given. The main recommendations contributing to an increase in the level of coal ash utilization in Russia are given.

According to various expert estimates, coal-fired thermal power plants of Russia annually generate 25...30 million tons of the coal ash, and its utilization rate is only 10...12%. Thus, each year 22...27 million tons of the coal ash is transported to the disposal sites, which are the sources of significant environmental pollution. To this day, more than 1.5 billion tons of the coal ash have been accumulated at the disposal areas of the Russian Federation, and their number is growing every year. According to the national plans of the Russian energy industry, coal remains one of the main energy resources, accounting for about 13% of the country's fuel balance. Globally, coal accounts for 36% of all primary sources in the production of heat and electricity; the main share of coal generation is observed in the developing countries – China and India.
In the Russian Federation, the situation is aggravated by the fact that the average age of the coal-fired thermal power plants is about 50 years, which cannot but affect the technical and environmental performance of the coal ash removal systems of thermal power plants, as well as the performance of power plants in general. In this regard, reduction of the negative impact of the fuel and energy complex industries on the environment and coal power, in particular, is one of the global state tasks according to the Energy Strategy of the Russian Federation for the period up to 2035. Thus, the main activities aimed at reducing the negative impact of fuel and energy facilities on the environment are:
• elimination of the accumulated environmental damage, restoration of degraded natural ecosystems;
• reduction or preventing the negative impact of economic activity on the environment and the rational use of natural resources.
The problem of the coal-fired thermal power plants in terms of eliminating the accumulated environmental damage can be solved only by implementing large-scale projects of the integrated coal ash processing to obtain demanded products.
In order to reduce or prevent the accumulation of the coal ash, it is necessary, first of all, to switch to the state-ofthe- art coal ash handling technologies and implement the principles of the Best Available Techniques, use water-free coal ash handling technologies, thereby expanding the range of the coal ash applications, as well as to form and develop the coal ash market in view of the requirements of consumers.
The article includes the classification of the coal ash removal systems of thermal power plant as well as the results of an overview and analysis of the coal ash handling equipment, including the systems of internal and external coal ash transport. It describes the schemes of the traditional coal ash removal system with the joint coal ash collection and conveying, the schemes with separate removal, storage and shipment of the coal ash, as well as the combined coal ash removal scheme. A promising technology of the bottom ash removal applied at thermal power plants is considered. Recommendations for the development of economical and environmentally friendly coal ash removal systems of thermal power plants are given.

Currently the aim of heat-saving energy sector is to increase the efficiency of consuming energy and fuel resources through the creation and modernization of technologies capable of efficient collection and long-term storage of heat energy. A more rational consumption of heat energy, being in use under supervision when needed, will make it possible to pass on to energy storage policy of resource consumption. However, one of the main factors determining the competitiveness of the developing low-energy technologies is the financial component. The core of thermal energy storage system, contributing up to 80 % to the cost of heat storage systems, are heat-accumulating materials. This raises the issues o f the optimization o f the developed storage technologies a nd of the use of heat energy in the required volume, which is accompanied by the need to test the created heat storage materials in practical exploitation. The article proposes a step-by-step approach to optimizing the properties of heat storage compositions to improve their efficient operation in a heat accumulator. This necessitates the consideration of the parameters that ensure the efficient and safe operation of heat accumulator due to the use of advanced phase change materials based on hydrate salts. The provided algorithm, consisting of a methodology for the selection of hydrate salts and a methodology for investigating heat storage materials, was tested in creating the heat storage material based on CH3COONa·3H2O, and there were shown the differences between the results presented in laboratory conditions and results presented in experimental conditions of the heat storage material. During the synthesis of a mixture of CH3COONa·3H2O and Na4P2O7·10H2O, the heat capacity in the liquid phase increased significantly from 2.37 for CH3COONa·3H2O to 5.64 for phase change heat storage materials, and the enthalpy of melting from 226 to 259.8 kJ/kg. Subcooling ΔT decreased from 90 to 1.45 °C, while the melting point remained at 58 °C. In these circumstances, the cost of phase change heat storage materials increased by 1.5 times compared to the starting acetate and amounted to 340 rubles/kg. This shows the significance of the results achieved during the testing of the efficiency of phase change heat storage materials under the conditions of the developmental prototype of the heat accumulator with the purpose of further optimization. The developed methodology is useful for researchers planning the industrial synthesis of derived phase change heat storage materials in order to avoid the low efficiency of the prototype

The paper proposes the use of graphene oxide as an alternative cathode material for primary current sources with a zinc anode in an alkaline electrolyte. A comparative analysis of the electrochemical behavior of systems based on Zn/graphene oxide and Zn/electrochemical graphene oxide were carried out. It is shown that, despite the smaller capacity, the main energy-power characteristics of electrochemical graphene oxide exceed the characteristics obtained for graphene oxide synthesized by the Hamers method. In the article, conclusions were drawn about the features of the electrochemical behavior of graphene oxide, depending on the method of preparation and type of electrolyte