The article present results of economic efficiency evaluation of storage technology for electricity from coal power plants in large-scale chemical batteries. The benefits of using a chemical lithium-ion battery in a public power plant based on hard coal were determined on the basis of data for 2018 concerning the mining process. The analysis included the potential effects of using a 400 MWh battery to optimize the operation of 350 MW power units in a coal power plant. The research team estimated financial benefits resulting from the reduction of peak loads and the work of individual power units in the optimal load range. The calculations included benefits resulting from the reduction of fuel consumption (coal and heavy fuel oil – mazout) as well as from the reduction of expenses on CO2 emission allowances.

The evaluation of the economic efficiency was enabled by a model created to calculate the NPV and IRR ratios. The research also included a sensitivity analysis which took identified risk factors associated with changes in the calculation assumptions adopted in the analysis into account. The evaluation showed that the use of large-scale chemical batteries to optimize the operation of power units of the subject coal power plant is profitable. A conducted sensitivity analysis of the economic efficiency showed that the efficiency of the battery and the costs of its construction have the greatest impact on the economic efficiency of the technology of producing electricity in a coal power plant with the use of a chemical battery. Other variables affecting the result of economic efficiency are the factors related to battery durability and fuels: battery life cycle, prices of fuels, prices of CO2 emission allowances and decrease of the battery capacity during its lifetime.

Solar photovoltaic (PV) and concentrated solar power (CSP) systems are the present worldwide trends in utilizing solar energy for electricity generation. Solar energy produced from photovoltaic cells (PV) is considered the main common technology used due to its low capital cost; however, the relatively low efficiency of PV cells has spotlighted development and research on thermal engine applications using concentrated solar power. The efficiency of concentrated solar power is greater than that of PV and considering the solar potential for Sudan. Therefore, this study has been performed in an attempt to draw attention to the utilization of CSP in Sudan since the share of CSP is insignificant in comparison with PV, besides the suitability of CSP applications to Sudan’s hot climate and the high solar energy resource, the study presents a design model of 1 MW parabolic trough collectors (PTC) using the Rankine cycle with thermal energy storage (TES) in Sudan, by adopting reference values of the Gurgaon PTC power plant in India. The design of a 1 MW Concentrated Solar thermal power plant using parabolic trough collectors (PTC) and thermal energy storage is proposed. The simulation was performed for a site receiving an annual direct normal irradiance (DNI) of 1915 kWh/m2, near Khartoum. The results showed that the plant can produce between nearly 0.6 to 1 MWh during the year, and around 0.9 MWh when it encompasses thermal energy storage with an average thermal efficiency of 24%. These results of the PTC Power plant encourage further investigation and the development of CSP technologies for electricity generation in Sudan.

The article reveals the problems of the formation and implementation of Ukraine’s energy policy

from the beginning of its independence to the present day. The specificities of the fuel and energy

sector of the country’s economy, the main stages of formation, macroeconomic conditions and the

problems of its transformation were analyzed. The slow and contradictory processes of reforming

Ukraine’s fuel and energy complex throughout the period of its independence and the fact that the

inconsistency with the main directions of the economic policy did not ensure its effective transformation

have been proven. The results of the OECD assessment of progress towards the main

objectives implementation of the Ukraine’s Energy Strategy have been presented. It was noted that

the results of the research suggest that the progress in achieving the goals of Ukraine’s Energy Strategy

is ambiguous, therefore the strategy needs to be refined accordingly. There are two main factors

moving away from the formal and declarative nature of Ukraine’s energy policy to its realistic model.

Firstly – an international factor associated with Ukraine’s extending involvement in international cooperation

within the energy sector, Ukraine’s international commitments to reform the energy sector

towards increasing energy efficiency, green energy, etc. Another – the crisis factor – as a result of the

energy policy of the Russian Federation. It was noted that the role of these factors in the future will

remain determining. The need to improve Ukraine’s energy policy, taking the current trends in the

development of the world energy system, new challenges and threats to politico-military and energy

confrontation with the Russian Federation into account, has been proven.

Taking debates on the historiography of Quebec as the base of his considerations, the Author presents various reflections and postulates concerning comparative historiography. In particular His attention is drawn to the various types and aspects of historical identity. The awareness of those is necessary for the correct comparative analysis.

This paper examines how Latvian communities abroad reacted to and were influenced by a change of the first magnitude in the political life of their homeland, namely, the proclamation of the Republic of Latvia on November 18, 1918. News of the proclamation, first of all, necessitated diaspora Latvians choosing attitudes towards the new phenomenon, which highlighted the political pre‑dispositions of the different groups within the diaspora. Polarisation of opinions was followed shortly by a wave of activities both in support of and against the new Republic. These activities included gathering financial resources for war victims and state institutions in Latvia, public relations campaigns in diaspora host countries, political lobbying etc. The establishment of the Republic of Latvia also profoundly influenced and intensified the internal formation processes within the diaspora. A marked increase of activity is observable in all fields of engagement that are characteristic of an active ethno‑national diaspora: the internal organisational structure was further developed; contacts with the homeland intensified; mutual links between geographically distant diaspora groups became closer. The great political changes in the homeland gave the Latvian diaspora the push necessary to fully develop and become an active ethno‑national diaspora.

W ciągu 2001 i 2002 roku skierowano do Europejskiego Trybunału Sprawiedliwości w Luksemburgu zapytania prejudycjalne w kilku sprawach dotyczących kwestii pomocy państwowej dla przedsiębiorstw świadczących usługi w ogólnym interesie gospodarczym. Chodzi w szczególności o definicję takiej pomocy oraz odpowiedź na pytanie. czy dofinansowanie przekazane z zasobów państwowych przedsiębiorstwom świadczącym usługi w ogólnym interesie gospodarczym jest taką pomocą, czy tylko wynagrodzeniem za świadczone usługi. jako że dotychczasowe orzecznictwo ETS było kontradyktoryjne, kwestia wymagł/a wyjaśnienia. Jedna ze skierowanych spraw do ETS dotyczyła pomocy udzielonej przedsiębiorstwom zarządzającym wyposażeniem technicznym w portach włoskich.

The paper presents experimental studies on boiling heat transfer in rectangular minichannels. The investigations focus on the transition from single phase forced convection to nucleate boiling, i.e., in the zone of boiling incipience. The experiment has been carried out with FC-72, R-123 and R-11 at the Reynolds number below 4700, corresponding to mass flow rate range 95-710 kg/(m s). The main part of the test section is a minichannel of pre-set depth from 0.7 to 2 mm and width (20, 40 and 60 mm), with different spatial orientations from vertical to horizontal and 30% inclination angle adjustment. The objective of the paper includes the impact of selected parameters (liquid flow velocity, pressure and inlet liquid subcooling, channel dimensions and spatial orientation) on the boiling incipience in minichannels. The investigations are intended to develop a correlation for the calculations of the Nusselt number under the conditions of boiling incipience in the minichannel as a function of changeable parameters.