Improving the efficiency of using solar energy for desalination of salty and polluted water is an urgent task for many regions of our planet. The great strides made in this area using ultrafiltration and reverse osmosis techniques have a high energy intensity of technology, which is extremely expensive to achieve using photovoltaic solar energy converters. The creation of new desalination technologies that require low expenditure of electrical energy requires the use of other physical mechanisms. The joint use of thermal distillation methods with the intensification of evaporation and condensation processes by low-energy-intensive ultrasonic dispersants and thermoelectric refrigerators is promising.In the current work, an experimental investigation study was conducted to show the effect of enhancing the evaporation and condensation processes inside a modified single solar still by combined ultrasonic humidifiers in the basin water inside a cotton mesh tent, in addition installing at the top of the solar still a cooling chamber with thermoelectric elements Peltier. The results showed that the productivity of the modified solar still increased by 124% than the traditional solar still.

Solar modules, which are used in photovoltaic power plants, are the primary sources of energy, and it is on their efficient operation that the generation of electricity by the station depends. During operation, solar modules can be exposed to various natural and man-made impacts. As a result, its effectiveness may decrease, or its may fail. The world practice of monitoring the state of an energy source at a solar power plant, based on measurements of the electrical parameters of PV-strings consisting of series-connected solar modules, does not fully reflect the changes in their possible states. There is practically no information about the performance of individual modules. In this regard, the development of mathematical models for the connections of photovoltaic converters (PVCs), methods for detailed monitoring and diagnostics of the technical condition of solar modules in order to detect violations in a timely manner and subsequently increase the efficiency of its operation in non-uniform lighting conditions, are urgent tasks that require new solutions.

An explicit analytical equation for the full current-voltage characteristic of a photovoltaic converter was obtained using the Lambert W-function for the forward and reverse branches. An electronic measuring unit was developed that allows automatically recording the current-voltage characteristic of converters, including the negative branch. When solar cells are connected in series under conditions of non-uniform illumination of its surface, some of the least illuminated solar cells stop working as energy sources and become “parasitic” loads. The bulk of the PV cells continue to generate power and pass current through the less illuminated PV cells, causing high energy losses in the form of heat dissipation, which can lead to the formation of hot spots and thermal damage to the PV cells. A significant influence of the reverse branch of the current-voltage characteristic of a photovoltaic converter on the generated power is shown. A method for composing solar modules from photovoltaic converters under their operating conditions with non-uniform illumination is proposed, the technical result is to increase the efficiency and reliability of the power plant by reducing the frequency of replacing failing solar modules due to the formation of local overheating points. A diagnostic unit for the solar module has also been developed, which allows you to automatically monitor the health status of each module and notify in a timely manner about the need for maintenance, repair or replacement of solar modules on the territory of a solar photovoltaic power plant.

The bioconversion of raw materials of ordinary cane into fermented sugars for the production of bioethanol is an urgent and dynamically developing area of research. The purpose of this work was to study two types of physicochemical pretreatment with alkali and acid of ordinary cane. Pretreatment with acid showed superiority over alkaline treatment in relation to the rate of enzymatic hydrolysis and, as a consequence, an increase in ethanol productivity. In a pretreatment medium with 6% acid in an autoclave, a high content of total reducing sugar (25.4 g/l) was shown. Fermentation of cane hydrolysates with Saccharomyces cerevisiae contributing to the yield of the product in the amount of 16.5 g/l of ethanol. The results of the conducted studies show that the biomass used is extremely relevant for the production of ethanol. In this regard, ordinary cane can be used for the production of bioethanol, and becomes a potential candidate for future production based on the results of the conducted research.

The issues of production and use of alternative fuels, namely bioethanol, problems and solutions are considered. It is shown that the use of new technologies to increase the efficiency of ethyl alcohol production opens up promising ways for the widespread use of bioethanol and increasing its competitiveness in the fuel market. The article examines the features of obtaining bioethanol from renewable sources.

The energy structure of most countries has changed in line with the trend toward "greening" energy in the world. For the most part, countries support the diversification of energy sources to ensure national interests and energy security. An adequate and reliable energy supply, especially electricity, is essential not only for economic development, but also for the social and political stability of the country.

This paper presents a general picture of global and nuclear power industry, including an overview of the Vietnamese electricity industry. The results of the analysis show that even with relatively modest energy consumption, Vietnam has faced a shortage of energy sources, so strengthening the development of Vietnam's electricity sector is an urgent need to ensure socio-economic development during the country's accelerating industrialization and modernization.

The current state of the world's energy industry and its development trends; the accelerating process of transition from conventional to renewable energy sources and its consequences; especially local energy crises in Europe, Asia, and the United States due to a too rapid transition in relatively harsh climatic conditions, as well as the aggravation of energy supply problems on a global scale due to extensive sanctions against Russia, are described. The results of the analysis show that in the long term, nuclear power is the best solution to the problem of reliable energy supply, not only in Europe, but all over the world.

The necessary conditions for the development of nuclear energy in Vietnam, including the existence of a legal framework and the preparations carried out by Vietnam from the beginning of the implementation of the nuclear energy development policy (1996) until the decision to stop construction of the first NPP (2016), in particular, the site preparation for the construction of NPPs in Ninh Thuan province, availability of uranium potential, available investments and finances, as well as training of personnel, are analyzed.

Recommendations for the future development of Vietnam's nuclear program are formulated.

Solving the problem of environmentally safe management of radioactive waste in addition to ensuring the safe operation of nuclear power plants is a main condition for the acceptability of nuclear power as a reliable source of electricity. The problem of liquid radioactive waste management is updated. The ion-selective purification method was chosen as the optimal option for liquid radioactive waste for final isolation of conditioned RW has been substantiated. High efficiency of new generation inorganic sorbents increases the efficiency of ion-selective sorption units provided that the problem of safe storage of spent medium and high activity sorbent in places of processing, transportation and burial is solved. In this connection, an important condition for realization of this technology is optimization of radiation protection of a container with radioactive waste. The task on optimization of the effective dose received from the spent filter-container is specified. The structure and dimensions of the container are stipulated. The protective materials for the inner capsule and the outer protective coating, as well as the material of the filler located between the capsule and the container shell are selected. Monte Carlo (MC) simulations with an input value of F6 and six detectors on each side of the container were performed to predict the released energy at a distance of 1 m from the outer shell of the container. The results of the analysis of the effect of the radioactive waste capsule material and its wall thickness, the type of the filler and its thickness on the radiation protection characteristics of the container are presented. Isotopes 137Cs and 60Co in concentrations of 90% and 10% respectively were chosen as solid RAW filling the container. Dependence of allocated energy, equivalent dose, changes in transmittance and radiation shielding coefficients on the material and thickness of the receiving capsule were obtained based on simulation results. Conclusions on the optimal parameters of the filter-container are formulated and the advantages of the investigated solutions are substantiated.

The paper presents the results of numerical simulation of the gasification process in a downdraft gasifier to produce syngas with high hydrogen content. For the first time the possibility of using dark fermentation digestate as a feedstock for thermochemical conversion using air as an oxidizer at equivalence ratio ER of 0.45, 0.55 and 0.65 was investigated. Modeling of the gasification process was carried out in the software package Comsol Multiphysics. As a result of numerical studies, the concentrations of the main components of the syngas were obtained. The syngas yield at air gasification was 1.8 m³/kg. At the same time the combustion heat of the generated gas varies from 3.1 to 3.9 MJ/m³ with the molar ratio MR being in the range from 3.1 to 3.9. The maximum specific gravity of hydrogen in the composition of syngas, equal to 26.94%, is achieved at ER = 0.45. The hydrogen production efficiency HPE ranges from 23.8 to 27.3 %. The thermal power that can be obtained from the syngas corresponds to 47 to 59 kW. Carbon conversion efficiency CCE is 23.6 - 28.8 %. The basic geometric parameters of downdraft gasifier were obtained based on the design calculation. The apparatus is designed to produce syngas from digestates of anaerobic fermentation. Obtaining the required concentrations of the necessary gas components will be done by varying the flow rate of the gasifying agent as well as by combining the ER. This study will increase knowledge in the field of complex technologies combining biological and thermochemical methods.

The wide spread of diesel-electric generators in our country is due to the need to reserve responsible energy consumers and private households, in cases of loss of centralized energy supply. The large territory of the country, the development of the Far Eastern and Arctic territories also leads to the need to use diesel-electric generators and organize the supply of large volumes of diesel fuel to these remote regions.

Unlike stationary thermal power plants, such autonomous power plants have practically no combustion product cleaning systems, have low efficiency, high specific fuel consumption, high cost of energy production, have a limited motor resource and need constant maintenance.

At the same time, the current level of development of direct methods of converting the chemical energy of fuel into an electric current based on electrochemical generators makes it possible to create an autonomous power plant operating on traditional fuels, devoid of these shortcomings.

This article considers an innovative technology of combined production of electric and thermal energy using the preliminary conversion of diesel fuel into gas synthesis, followed by its supply to a high-temperature electrochemical generator. A scheme of the full technological cycle of the installation, including the air conversion of diesel fuel into synthesis gas and its further use in SOFC and waste heat boiler, has been developed. On the basis of heat balances of the burner, ECG and waste-heat boiler-utilizer, electrical efficiency of the solid oxide fuel cells’ (SOFC) battery, chemical efficiency of the burner, the temperature at the SOFC anode, the EMF of the planar cell, a portion of hydrogen oxidized at the SOFC anode, specific consumption of diesel fuel for the production of electrical and heat power were calculated. Specific consumption of diesel fuel for the production of electrical and heat power was found to be equal to 114 g/kWh (162 g r.f./kW·h) and 31.7 kg/GJ (45.1 kg r.f./GJ, 189 kg r.f./ Gcal), respectively. Specific consumption of diesel fuel corresponds to a high-efficient heat power-station and more than 3 times lower than in modern diesel generators of equal power.

The use of bioethanol as a fuel reduces emissions of carbon dioxide, a greenhouse gas. Due to environmental concerns, the search for sustainable fuel alternatives has become mandatory, with the most promising alternative being the use of biomass as an energy source and also to reduce CO₂ emissions. Bioethanol is the main type of biofuel that can be produced from lignocellulosic materials. Its production usually involves a hydrolysis-fermentation consisting of three main steps: pretreatment to produce fermentable sugars, fermentation to produce bioethanol, and a separation process to produce highly concentrated bioethanol. One of them is the ratio of cost to the target volume of production, due to pre-processing operations.

Projects for large gigawatt-class tidal power plants are currently being developed in the Russian Federation and elsewhere in the world. Such power plants are designed to operate in the energy system in conjunction with thermal and nuclear power plants. If there is no suburban power plant in the construction zone, it is planned to build complexes based on the use of periodic variable generation capacity, for example, for the production of hydrogen. At the same time, in the zones of intensive tidal water traffic, relatively small energy consumers are often located - fishing artels, meteorological and border posts, etc. This work considers the designs of incorporeal tidal hydroelectric power plants, since the dam is the most expensive construction of an tidal hydropower plants and its construction is economically unprofitable for individual use or for small settlements that consume electrical power of several tens of kilowatts. The principle of operation of incorporeal tidal hydropower plants is outlined. Conclusions are made about the advantages of using this type of installation in the power range from 10 to 100 kW.

The article presents the materials of research work related to a non-standard methodological approach to assessing the contribution of pollution from motor transport, which became possible due to the pandemic that broke out on the planet and restrictive measures on COVID-19. A new approach to the assessment of pollutants from automobile emissions entering surface water bodies from the atmosphere was considered, based on a comparison of monitoring data for the period: 2019 – 2020. The work reflects the results of the analysis of the dynamics of the air and water state in the Ural river, as well as its right-hand tributary – the Sakmara river near the town Orenburg in the period 2019-2020. The impact of restrictive measures on COVID-19 on the degree of air pollution in the town Orenburg and water in the Ural and Sakmara rivers is estimated. Studies have shown that in 2020, compared with the previous year, the traffic intensity of cars decreased by 20%, and during the lockdown period (April – May) by 60%, which led to a reduction in the air content of pollutants such as carbon monoxide, sulfur dioxide, nitrogen oxide and nitrogen dioxide, and in the water of both rivers: suspended solids; common iron; nitrite and nitrate nitrogen. A comparison of the data obtained allowed us to apply a new approach to assessing the specific contribution of one conditional car to the pollution of the Ural and Sakmara rivers. This contribution, consisting in the insufficient intake of absolute values of pollutants into the water of rivers, due to the conditional downtime of 1 car in 2020 due to restrictions on COVID-19, amounted to 175.0 and 696.5 kg/year for the Ural and Sakmara rivers, in particular, for suspended solids, respectively; for general iron – 0.545 and 0.727 kg/ year; the sum of nitrite and nitrate nitrogen – 0.657 and 0.923 kg / year. It is noted that these are estimated calculations that demonstrate how to use the unique data that have developed as a result of the announcement of restrictive measures for the outbreak of a pandemic to assess difficult-to-diagnose diffuse effluents.