The article presents brief information about the potential of solar energy in Uzbekistan and overview of devices that in various ways make it possible to clean the optical surface of photovoltaic battery from dust. In current natural and climatic conditions in many countries of the world the average annual concentration of particulate matters is several times higher than the norm, which in turn has a negative impact on the efficiency and productivity of solar modules of solar power stations, it is in context that there is a need to develop, create and use a device for their purification. Therefore, the author has developed, created and used a device that cleans the optical surface of a photovoltaic battery from dust. In order to increase the level of efficiency, as well as ease of operation, a mechatronic system and its schematic diagram have been developed. In order to study the efficiency of the device on September 29 2023 experimental studies of a photovoltaic battery, which was equipped with the developed device, were carried out at the laboratory site of the Tashkent State Technical University. The study revealed that that all electrical parameters of the cleaned photovoltaic battery were significantly higher than those of the uncleaned battery. For example, at 12:08, when solar radiation reached 584 W/m2, the short circuit current, output power and efficiency of the cleaned battery were 6,17 A, 151 W and 10,34% respectively, which compared with the parameters the uncleaned battery is 7,30%, 10,21% and 10,23% more. Therefore, the device can be successfully used for solar modules of solar photovoltaic station or for photovoltaic batteries that are installed on the roof of various buildings and houses of the population.

This article presents the results of studies of the physical properties of hydrogenated amorphous thin films of α-Si1-xGex:H and α-Si1-xCx:H alloys obtained by plasma chemical deposition. The optical constants (n, n1, α, R, d) and the band gap of the films under study (E0 = 1,05 ÷ 3,00 eV) were determined. Based on a study of the optical properties of various deposition modes (Tpod, d, H2), the substrate temperature, film thickness and the level of hydrogenation of the alloys are characterized by different structural phases. With a change in technological parameters, various structural and polymer phases of crystallites are also obtained: nanotubes, nanowires, nanoparticles, quantum wells, quantum dots, graphenes, graphites, decanters, fullerenes, diamond particles, clusters, etc.

The structure of the deposited nc-Si:H films is mixed-two-phase and consists of nc-Si:H nanocrystallites «distributed» in an amorphous network. Annealing of crystalline films at a temperature of 700 оC increases the crystallite size to 50 ÷ 100 Aо in diameter, and the conductivity changes slightly. Also, when hydrogen is introduced into an amorphous silicon film at low temperatures (Ts ≤ 100 оC) with a higher hydrogen content (≈ 30 atm.% or more), the material contains an excess of the SiH3 group, as well as slightly more hydrogen in the polymer form (SiH2)n. The concentration of carbon and hydrogen in α-Si1-xCx:H films depends on the deposition conditions and the initial gas mixture of SiH4, CH4, H2. Depending on the choice of modes, with increasing concentrations of hydrogen H2 and CH4, films are deposited in polymer form.

Every year there is a steady development of the solar power industry, supported by various countries around the world. In this regard, the task is to reduce the cost of production of photovoltaic converters and increase their efficiency. Against this background, more and more people are moving away from traditional silicon technologies in search of a solution to this problem. One of the promising areas for further development are quantum dots solar cells due to their unique properties, stability during operation and the possibility of their environmentally friendly production. The aim of the work is to study the current state of development of photovoltaic converters based on quantum dots. The field of research is solar power engineering. To solve this problem, various materials of domestic and foreign scientific publications on the subject of solar energy were systematized. Photovoltaic converters based on quantum dots and methods of their production are considered, forecast for their further promising use in solar energy is given.

Comprehensive studies on cleaning the surface of photovoltaic batteries (PVB) from snow and ice cover are analyzed, and the effect of snow cover on the main operating parameters of the PVB is studied. A method of cleaning the surface of the FEB from snow using an energy-saving heating element (infrared film material) is proposed. A photovoltaic installation has been developed that is equipped with an infrared-film electric heater on a carbon base.
On January 15, 2023, experimental studies were conducted to clean snow on the surface of one FEB and one row of a 10 kW photovoltaic power plant (FES) based on polycrystalline silicon, covered with snow 12 cm thick. From the analysis of the experimental results, it follows that the electricity generation of the FES covered with snow decreased by 80-90% in comparison with the results measured in semi-cloudy winter weather. As a result of the use of an infrared film electric heater, the efficiency coefficient (efficiency) of this FEB has been restored. Numerous experiments show that to clean the front surface of the FES (40 pieces of FEB) with a total power of 10 kW, the infrared film electric heater consumed only 1,7 kWh of electricity.
Experiments continued to study the effect of cleaning the surface of a 290 W FEB covered with 50 mm thick snow from the FEB control unit for two days on January 25-26, 2024. It should be noted that the efficiency of the FEB decreased to 1,5-2% with snow and clouds. This is explained by the dependence of the thickness of the snow cover on the frontal surface of the FEB on the magnitude of the solar radiation flux density in winter. After actively cleaning the frontal surface of the FEB from snow cover using an efficiency device, of both FEBs were equalized within 25 min.

This article examines the analysis of the possibility of using renewable energy sources to increase electricity production in the territories of small hydroelectric power stations. The development of the manufacturing industry for the economic development of countries, an increase in population and other reasons will lead to an increase in the demand for electrical energy. Expanding the scale of energy production and, as a result, the release of various harmful gases into the environment. In addition, climate change is causing problems with water supply at hydroelectric power plants. One of the options for reducing gas consumption is considered: the use of low-waste renewable energy sources for energy transportation. The possibilities of increasing energy efficiency in the territories of power plants to reduce losses during energy transmission were also analyzed. The studies were conducted in the Namangan region and showed positive results.

A potential raw material for producing hydrogen (the main carrier for the accumulation, storage and transportation of energy) is methane from biogas. An approach to producing biogas with a high methane content (69-72%) from waste commercial dry and wet food for dogs and cats under mesophilic conditions has been demonstrated. For 27-28 days under anaerobic conditions, the degree of biotransformation of waste was 60-88%. As a result of mineralization of watered organic waste, the content of ammonium nitrogen and phosphorus in the form of phosphates amounted to 676-887 mg NH4 +/l and 77-160 mg PO4 3-/l, respectively. In anaerobically treated effluent, accumulation of sulfide ions up to 22 mg/l was observed. The solid sediment and anaerobically treated effluent (liquid fraction) obtained upon completion of the biotransformation of pet food waste are a potential organic fertilizer for agricultural needs, and methane from biogas is a raw material for producing hydrogen and pure carbon for the needs of the nanoindustry.

Although two-stage anaerobic digestion (TSAD) is not a novel process, information of the process stability, microbial community and effective operating conditions is limited and often contradictory. In this work, the influence of different carrier materials (polyurethane foam, carbon felt, Raschig rings and a combination of carbon felt and Raschig rings) on the performance of the thermophilic TSAD of dairy wastewater was studied. The organic loading rate (OLR) in the acidogenic reactor (RH) was gradually increased from 13,74 to 32,56 g COD/(L∙d), and from 0,64 to 11,46 g COD/(L∙d) in the methanogenic reactors by correspondingly reducing the hydraulic retention time (HRT). The highest hydrogen production rate of 1280,3 ml/(L·d) and hydrogen yield of 93,2 ml/g COD were achieved at OLR of 13,74 g COD/(L·d), but hydrogen production stopped at higher OLR. The main soluble metabolites in RH were butyrate and lactate, and the microbial community was dominated by Streptococcus, Thermoanaerobacterium, Veillonellales- Selenomonadales and Pseudomonas. The highest methane production rate (2674 mL/(L·d) at HRT of 0,5 days) was observed in the reactor with polyurethane foam, while the highest methane yield (305,5 ml/g COD at HRT of 1,5 days) was obtained in a reactor containing carbon felt. Spirochaetaceae, Desulfomicrobium, Anaerolineaceae, Candidatus Caldatribacterium and Cloacimonadaceae W5 were linked to these materials and explained the highest methanogenic performance.

This work is aimed at a comprehensive solution to the problem of reliable and safe operation of a transport energy system with a high energy concentration based on a universal energy carrier – cryogenic liquid hydrogen.

The article discusses the possibility of using various methods and techniques to assess the reliability of machines and equipment operated in emergency situations and extreme conditions. The obtained results are analyzed.

Currently, the oil and gas complex pays great attention to the development of hydrogen technologies, as well as hydrogen energy in connection with the relevance of the Climate Agenda. In this regard, hydrogen energy facilities are of the greatest interest: cryogenic hydrogen reservoirs, cryogenic hydrogen pipelines, cryogenic oxygen reservoirs and cryogenic oxygen pipelines, as well as cryogenic reservoirs and pipelines for storing process nitrogen gas. An important role for global energy exchange is played by LH2 tankers for transporting cryogenic hydrogen. For example, Australia and Japan built the first LH2 tanker to transport hydrogen from Australia to Japan. In addition, another 85 LH2 tankers are expected to be built.

After transportation, cryogenic hydrogen is stored in cryogenic hydrogen storages, usually also representing cryogenic hydrogen tanks with piping in the form of cryogenic pipelines, as well as cryogenic nitrogen tanks for storing process nitrogen gas. Further, hydrogen is used in road transport, aviation, ship fleet, industry, and energy. The main elements of mobile, stationary and airborne hydrogen storage systems are under critical loads and are in the area of increased study and attention.

In this regard, we considered the functions of changing the main operational characteristics, made proposals on the possibility of predicting the development of accumulated faults and proposals for ensuring safety and extending the life of objects, taking into account the determination of local and integral damage to cryogenic tanks and pipelines.

The article reviews existing approaches to low-carbon hydrogen certification and offers recommendations for their improvement based on an assessment of the carbon footprint across the entire life cycle. A comprehensive assessment of the carbon footprint of hydrogen produced from water and methane during steam reforming is presented. The assessment concluded that approximately 50% of hydrogen is produced from water, meets the requirements of low-carbon hydrogen(emission levels in the range of 4,2-4,5 kg CO2eq/kg H2) and can be considered for certification as renewable hydrogen. The results of estimating the carbon footprint of hydrogen from hydrogen sulfide demonstrate that for hydrogen sulfide conversion of methane and thermal decomposition of hydrogen sulfide, carbon dioxide emissions will be on the order of 1,842 and 2,244 kg CO2/kg H2, respectively. Taking into account associated emissions from natural gas production, the total greenhouse gas emissions for the processes under consideration are 4,649 and 6,129 kg CO2eq/kg H2, respectively, when using grid electricity. When using electricity from hydropower, the total greenhouse gas emissions from hydrogen production through hydrogen sulfide conversion of methane and thermal decomposition of hydrogen sulfide will be 2,33 and 2,78 kg CO2/kg H2, respectively, and for an alkaline electrolyzer they are about 2,60 kg CO2/kg H2. Thus, when using low-carbon sources of electricity to power processes, hydrogen sulfide technologies perform comparable to water electrolysis processes, and in some cases even show lower emissions.

Additionally, the impact of hydrogen leaks on the greenhouse effect is considered and analyzed, which allows us to conclude that hydrogen is an indirect greenhouse gas.

The paper considers the prospects for creating autonomous hybrid power plants using renewable energy sources and hydrogen as energy storage systems, as well as storage batteries, for the railway power supply system. A comparative analysis of various energy storage systems is carried out. A simulation model has been created that takes into account the characteristics of electric rolling stock trains, a model of the contact network of the inter-station zone of the railway stage, and a model of the energy storage system. Managing the flow of electricity in an autonomous hybrid power plant requires considering forecasts of electricity consumption and generation and the level of charge of the energy storage device. To solve the problem of synthesizing a control algorithm, the use of matrix Q-learning is proposed. The novelty of the study lies in the proposed approach of applying Q-learning to the problem under consideration based on discretization of input and output parameters of the model and verification of the approach on a simulation model built for a real railway section between the Yaya and Izhmorskaya stations (Kemerovo region of the Russian Federation). It is shown that the use of the proposed system makes it possible to equalize the voltage in the network between traction substations and provide a significant increase in the capacity of the railway section, and the proposed method of matrix Q-learning makes it possible to synthesize an effective algorithm for controlling the energy storage system as part of an autonomous hybrid power plant.

Conventional fossil fuel-powered vehicles are gradually being replaced by electric and hydrogen vehicles in the transportation sector. Even with all the recognized benefits and recent advancements in energy efficiency, decrease of noise, and environmental impact reduction, the market of electric and hydrogen mobility is still not up to par. Allocating charging stations in metropolitan areas for electric vehicles is considered as one of the most significant obstacles preventing electric and hydrogen vehicles from becoming more widely used. In this paper, an efficient approach aimed at finding optimal locations for electric vehicles (EV) charging stations in urban areas is proposed. Particle Swarm Optimization algorithm technique is utilized with the proposed approach. Various parameters were taken into consideration in this work, such as the horizontal distance that EVs travel to reach charging stations (CSs), and positive slope that EVs face to reach charging stations. The optimization problem is formulated as a Mixed-integer problem. The objective function works on minimizing the energy consumption of EVs to reach CSs in the investigated area. Difference constraints are incorporated with the proposed approach in order to increase the accuracy and efficiency of the proposed approach. The proposed approach is applied on real world datasets and is experimentally validated using through comparison with Genetic Algorithm and the greedy approach. The results demonstrate that the proposed approach saves energy about 22% and 43% compared to the genetic algorithm and greedy technique, respectively.

Fuel cell technology emerges as a promising green solution, offering mitigation to global warming, air pollution, and energy crises. This eco-friendly approach is witnessing a surge in adoption within the automotive sector, with fuel cell buses, cars, scooters, forklifts, and more, becoming increasingly prevalent. The automobile industry has been rapidly advancing fuel cell technology, inching closer to the commercialization of fuel cell vehicles. As various technical hurdles are surmounted and costs are reduced, fuel cell vehicles are poised to become a competitive force in the automobile market, presenting an excellent solution for environmental sustainability and energy efficiency. This review paper delves into the fundamentals of fuel cells, their characteristics, and their applications in the automotive realm, exploring their prospects in comparison to traditional technologies. Furthermore, it sheds light on the existing research and industrial developments in hydrogen and fuel cell technologies. Additionally, a comprehensive comparison is provided between various fuel cell cars that have already been commercialized, enabling readers to understand the current market landscape. The review also analyses the advantages and challenges associated with fuel cell technology,offering insights into its future development trajectory. Through this comprehensive exploration, readers can gain a deeper understanding of fuel cell technology and its potential in revolutionizing the automotive industry.