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Tariffs for energy and energy resources are the main factors determining the sustainable development of the economy. The aim of the paper is to determine and compare the dynamics evolution of the tariffs for thermal energy and the evolution of the gross domestic product (GDP).The data on the heat consumption and tariff change in the city of Chisinau were examined in monetary terms and in relative units compared to the base year 2009. The higher the tariffs, the more part of the GDP, characterized in the economy by the volume of "Output", is spent on "Intermediate consumption (PP)". The difference between "Output" and "Intermediate consumption" volumes is the "gross added value (VAB)", which is the main component of GDP. The analysis of the changes in the real GDP volume of the Republic of Moldova and the increase of the tariffs for the years 2009-2017 (taking into account the GDP forecast for 2018) show that the increase in the tariffs for thermal energy significantly exceeded the real GDP growth. Considering that the planned GDP growth is 4,7% and taking into account the change in the consumer price index (inflation rate), the calculated reduction of the thermal energy tariff in Chisinau is estimated at 28% compared to the existing value, so to 803 lei / Gcal compared to the currently regulated value of 1122 lei / Gcal. The conclusion was reached on the opportunity of applying the proposed methodology to justify current tariffs and in the near future not only extends to thermal energy tariffs, but also for other types of energy, material resources and services in the field of production and social sphere.

Tariffs for energy and energy resources are the main factors determining the sustainable development of the economy. The aim of the paper is to determine and compare the dynamics evolution of the tariffs for thermal energy and the evolution of the gross domestic product (GDP).The data on the heat consumption and tariff change in the city of Chisinau were examined in monetary terms and in relative units compared to the base year 2009. The higher the tariffs, the more part of the GDP, characterized in the economy by the volume of "Output", is spent on "Intermediate consumption (PP)". The difference between "Output" and "Intermediate consumption" volumes is the "gross added value (VAB)", which is the main component of GDP. The analysis of the changes in the real GDP volume of the Republic of Moldova and the increase of the tariffs for the years 2009-2017 (taking into account the GDP forecast for 2018) show that the increase in the tariffs for thermal energy significantly exceeded the real GDP growth. Considering that the planned GDP growth is 4,7% and taking into account the change in the consumer price index (inflation rate), the calculated reduction of the thermal energy tariff in Chisinau is estimated at 28% compared to the existing value, so to 803 lei / Gcal compared to the currently regulated value of 1122 lei / Gcal. The conclusion was reached on the opportunity of applying the proposed methodology to justify current tariffs and in the near future not only extends to thermal energy tariffs, but also for other types of energy, material resources and services in the field of production and social sphere.

The analysis of the world electric-energy balance revealed the advantage of steam turbine plants. An increase in their efficiency through the improvement of the initial parameters runs into difficulties associated with creation of new materials. The efficiency increase that results from the final pressure reduction requires an improvement of the circulating water supply system. The aim of this work is to determine the effect of the water-cooling tower on the electric power station profitability. This goal was reached by the creation of a mathematical model of the water-cooling tower and turbine plant with a condenser connected to each other. The calculations were made for two types of cooling tower fill packing: asbestos cement sheets and mesh elements made of polyethylene. Further, according to it, the vapor condensation temperature was determined. The latter affects the vapor discharge in the condenser, the capacity of the turbine plant and the temperature of the cooling water at the condenser output, i.e. at the cooling tower input. The novelty of this work consisted of consideration of the interaction between the cooling tower and turbine plant. Significance of the obtained results lies in the fact that, taking into account the reciprocal influence of the turbine plant and cooling tower, the efficiency of the fill packing replacement turns out to be major comparatively to the case without considering this influence. The replacement of the fill packings the half-a-year average temperature of condensation will become lower by 2.34 °С, electricity production increases by 41.72 GWh.

The analysis of the world electric-energy balance revealed the advantage of steam turbine plants. An increase in their efficiency through the improvement of the initial parameters runs into difficulties associated with creation of new materials. The efficiency increase that results from the final pressure reduction requires an improvement of the circulating water supply system. The aim of this work is to determine the effect of the water-cooling tower on the electric power station profitability. This goal was reached by the creation of a mathematical model of the water-cooling tower and turbine plant with a condenser connected to each other. The calculations were made for two types of cooling tower fill packing: asbestos cement sheets and mesh elements made of polyethylene. Further, according to it, the vapor condensation temperature was determined. The latter affects the vapor discharge in the condenser, the capacity of the turbine plant and the temperature of the cooling water at the condenser output, i.e. at the cooling tower input. The novelty of this work consisted of consideration of the interaction between the cooling tower and turbine plant. Significance of the obtained results lies in the fact that, taking into account the reciprocal influence of the turbine plant and cooling tower, the efficiency of the fill packing replacement turns out to be major comparatively to the case without considering this influence. The replacement of the fill packings the half-a-year average temperature of condensation will become lower by 2.34 °С, electricity production increases by 41.72 GWh.

The work solves the problem of assessing the operation modes of the Integrated Power System (IPS) of Ukraine taking into account the power flows increase to the states borders for integration into the ENTSO-E power system. The Transmission System Development Plan for 2021-2030 is considered, in which the construction of southern transit power lines is planned. The issue of the redistribution of power flows in the electric network with the possibility of transferring power from the eastern regions of Ukraine to the western ones is considered. The analysis of the optimal increase in the connection cross-section into ENTSO-E networks by introducing southern transit. The purpose of the work is to analyze and evaluate the introduction of southern transit power lines by a high voltage direct current network based on voltage source converters in the electric network of the Ukraine power system. This problem was solved with creating a model of an electric network of 750 and 330 kV of the Ukraine IPS, analyzing the simulation results and comparing the network operation modes when introducing southern transit by an alternating and direct current. The most significant results of the work are the proof of the technical feasibility of introducing southern transit on direct current with the ability to influence the capacities flow distribution. Significance of the obtained results consists in the development of the Ukraine IPS model with the direct current lines introduction, which allows to analyze the electric network operating modes while introduction of southern transit by direct current.

The work solves the problem of assessing the operation modes of the Integrated Power System (IPS) of Ukraine taking into account the power flows increase to the states borders for integration into the ENTSO-E power system. The Transmission System Development Plan for 2021-2030 is considered, in which the construction of southern transit power lines is planned. The issue of the redistribution of power flows in the electric network with the possibility of transferring power from the eastern regions of Ukraine to the western ones is considered. The analysis of the optimal increase in the connection cross-section into ENTSO-E networks by introducing southern transit. The purpose of the work is to analyze and evaluate the introduction of southern transit power lines by a high voltage direct current network based on voltage source converters in the electric network of the Ukraine power system. This problem was solved with creating a model of an electric network of 750 and 330 kV of the Ukraine IPS, analyzing the simulation results and comparing the network operation modes when introducing southern transit by an alternating and direct current. The most significant results of the work are the proof of the technical feasibility of introducing southern transit on direct current with the ability to influence the capacities flow distribution. Significance of the obtained results consists in the development of the Ukraine IPS model with the direct current lines introduction, which allows to analyze the electric network operating modes while introduction of southern transit by direct current.

В статье рассмотрены наиболее распространение типы накопителей энергии, используемые для транспортных средств. Показано, что существующие критерии не могут дать полную оценку накопителей энергии для автономных транспортных средств, т.к. не учитывают транспортную составляющую. Предложено дополнить существующие критерии тремя новыми (доработанными) показателями, которые учитывают затраты на транспортировку накопителей энергии. Выполнен анализ накопителей энергии, которые используются на конкретных транспортных средствах, с учетом предложенной системы критериев. At present, in the majority of autonomous vehicles, the energy source is power units based on internal combustion engines. As known, such power units provide optimum economical operation in only one power, speed and temperature operating mode, and in other modes, their energy effi ciency (fuel consumption) is much, sometimes several times, lower than in the optimal mode. Therefore, the greatest prospectives in the fi eld of energy savings lie in the research that will allow the internal combustion engine work in the optimal mode under all motion modes of a vehicle. The coeffi cient of effi ciency of the transport system with non-autonomous vehicles that draw power from a contact network are largely dependent on the relative position of vehicles and traction substation. Being near substations or working in stopping mode and not regenerative braking, traction network losses are low, still in the other modes they can reduce the overall effi ciency of the system by tens of percent’s. One of the solutions to these problems is the use of energy storage devices that ensure economical operation of autonomous power plants, improve the dynamic performance of vehicles, and improve the effi ciency of their support systems. The paper presents the most common types of energy storage devices for vehicles: electrochemical, condensing, mechanical and pneumatic. The substantiation of criteria for evaluating the effectiveness of energy storage for vehicles, taking into account the cost of transporting them. The criteria suggested for assessing the energy storage of vehicles allow conducting comparative analysis of different, at nominal parameters and principles of action, devices, according to their use on vehicles where transport costs can be signifi cant. The conducted analysis of specifi c examples of energy storage devices and vehicles has led to the following conclusions: for the most of considered vehicles, the best performance based on the criterion of specifi c energy costs are gel batteries AGM, and in terms of specifi c power ratings cost - the mechanical energy storage.

В статье рассмотрены наиболее распространение типы накопителей энергии, используемые для транспортных средств. Показано, что существующие критерии не могут дать полную оценку накопителей энергии для автономных транспортных средств, т.к. не учитывают транспортную составляющую. Предложено дополнить существующие критерии тремя новыми (доработанными) показателями, которые учитывают затраты на транспортировку накопителей энергии. Выполнен анализ накопителей энергии, которые используются на конкретных транспортных средствах, с учетом предложенной системы критериев. At present, in the majority of autonomous vehicles, the energy source is power units based on internal combustion engines. As known, such power units provide optimum economical operation in only one power, speed and temperature operating mode, and in other modes, their energy effi ciency (fuel consumption) is much, sometimes several times, lower than in the optimal mode. Therefore, the greatest prospectives in the fi eld of energy savings lie in the research that will allow the internal combustion engine work in the optimal mode under all motion modes of a vehicle. The coeffi cient of effi ciency of the transport system with non-autonomous vehicles that draw power from a contact network are largely dependent on the relative position of vehicles and traction substation. Being near substations or working in stopping mode and not regenerative braking, traction network losses are low, still in the other modes they can reduce the overall effi ciency of the system by tens of percent’s. One of the solutions to these problems is the use of energy storage devices that ensure economical operation of autonomous power plants, improve the dynamic performance of vehicles, and improve the effi ciency of their support systems. The paper presents the most common types of energy storage devices for vehicles: electrochemical, condensing, mechanical and pneumatic. The substantiation of criteria for evaluating the effectiveness of energy storage for vehicles, taking into account the cost of transporting them. The criteria suggested for assessing the energy storage of vehicles allow conducting comparative analysis of different, at nominal parameters and principles of action, devices, according to their use on vehicles where transport costs can be signifi cant. The conducted analysis of specifi c examples of energy storage devices and vehicles has led to the following conclusions: for the most of considered vehicles, the best performance based on the criterion of specifi c energy costs are gel batteries AGM, and in terms of specifi c power ratings cost - the mechanical energy storage.