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Number of results: 11
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Abstract

The paper investigates the supply structure of the capacity market in Poland in the coming years. The results of the capacity auctions conducted in 2018 are analyzed for this purpose. Three auctions were held at that time. The products traded in the capacity market are capacity obligations for the following years: 2021, 2022 and 2023. The auctions were organized in accordance with (i) he Act of December 8, 2017 on the Capacity Market and the (ii) Capacity Market Regulations published by the Polish Power Grid. The source of data used in this study is the official information of the President of the Energy Regulatory Office on the final results of the main auctions for 2021–2023 delivery periods. The list of the capacity suppliers who won capacity auctions contains the type of capacity market units, the volume of capacity obligations, the duration of capacity agreements and the business name of the capacity suppliers. The conducted analysis indicates that the auction for 2021 was won mainly by existing units (45.81%) and refurbishing units (33.51%). In subsequent years, the share of existing generating units is significantly higher and amounts to 91.67% for 2022 and 84.54% for 2023. The results of the study carried out in this paper also show that one energy company, being the owner of power generating daughter companies, has a very high share in these capacity auctions. The PGE Capital Group contracted 51.95% for 2021, 69.92% for 2022 and 64.44% for 2023 of the total capacity obligation. The volume amounts to over 70% of their total installed capacity.

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Authors and Affiliations

Aleksandra Komorowska
ORCID: ORCID
Jacek Kamiński
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Abstract

The sustainable management of energy production and consumption is one of the main challenges of the 21st century. This results from the threats to the natural environment, including the negative impact of the energy sector on the climate, the limited resources of fossil fuels, as well as the unstability of renewable energy sources – despite the development of technologies for obtaining energy from the: sun, wind, water, etc. In this situation, the efficiency of energy management, both on the micro (dispersed energy) and macro (power system) scale, may be improved by innovative technological solutions enabling energy storage. Their effective implementation enables energy storage during periods of overproduction and its use in the case of energy shortages. These challenges cannot be overestimated. Modern science needs to solve various technological issues in the field of storage, organizational problems of enterprises producing electricity and heat, or issues related to the functioning of energy markets. The article presents the specificity of the operation of a combined heat and power plant with a heat accumulator in the electricity market while taking the parameters affected by uncertainty into account. It was pointed out that the analysis of the risk associated with energy prices and weather conditions is an important element of the decision-making process and management of a heat and power plant equipped with a cold water heat accumulator. The complexity of the issues and the number of variables to be analyzed at a given time are the reason for the use of advanced forecasting methods. The stochastic modeling methods are considered as interesting tools that allow forecasting the operation of an installation with a heat accumulator while taking the influence of numerous variables into account. The analysis has shown that the combined use of Monte Carlo simulations and forecasting using the geometric Brownian motion enables the quantification of the risk of the CHP plant’s operation and the impact of using the energy store on solving uncertainties. The applied methodology can be used at the design stage of systems with energy storage and enables carrying out the risk analysis in the already existing systems; this will allow their efficiency to be improved. The introduction of additional parameters of the planned investments to the analysis will allow the maximum use of energy storage systems in both industrial and dispersed power generation.
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Authors and Affiliations

Paweł Jastrzębski
Piotr W. Saługa
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Abstract

In spite of the negotiations initiated in 1972 Poland and Denmark have not so far managed to effect a delimitation of their maritime areas between Bornholm and Polish coast. This situation constitutes the longest lasting case of unsettled maritime boundary in the Baltic Sea. Even though both countries are parties to 1982 United Nations Convention on the Law of the Sea, they present different interpretation of art. 74 of the Convention, which states that the delimitation of the exclusive economic zones of the States with opposite coasts „shall be effected by agreement on basis of international law, as referred to in Article 38 of the Statute of the International Court of Justice, in order to achieve an equitable solution Consequently, Denmark considers the disputed area should be divided on the basis of median line. On the contrary, Poland invoke the international judgements and the practice of the States and indicates that boundary should be determined in accordance with the equitable principles, with regard for an existance of several special cicumstances, namely geographic and geophysical factors and proportionality calculations. Since the postures of the parties involved are overlapping, there exists south and southeast of Bornholm a disputed area of 3 500 km2, similar to this one existing between Gotland and the USSR coast before 1988. The relevant acts of national legislations of either Poland or Denmark illustrate these different claims. Nevertheless, during the recent negotiations round the parties agreed to create a special commitee of experts in aim to examine all the possible boundary lines. This fact confirms that it still may be possible for both countries to reach an agreement in bilateral negotiations.

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Authors and Affiliations

Tomasz Górski
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Abstract

A steam generator in a nuclear power plant with a light water reactor is a heat exchanger, in which the heat is being transferred from the primary to the secondary loop (it links the primary and secondary loops). When the power plant is running, the inlet parameters (temperatures and mass flow rates) on both sides of the steam generator can change. It is important to know how the changes of these parameters affect the steam generator performance. The complexity of the processes taking place in the steam generator makes it difficult to create a simulator reflecting its performance under changed conditions. In order to simplify the task, the steam generator was considered as a ‘black box’ with the aim of examining how the changes of the inlet parameters affect the changes of the outlet ones. On the basis of the system (steam generator) response, a simple mathematical model of the steam generator under variable load conditions was proposed. In the proposed model, there are two dimensionless parameters and three constant coefficients. A linear relation between these dimensionless parameters was obtained. The correctness of the model was verified against the data obtained with a steam generator simulator for European Pressured Reactor and AP-600 reactors. A good agreement between the proposed model and the simulator data was achieved.

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Authors and Affiliations

Rafał Laskowski
Janusz Lewandowski
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Abstract

The paper focuses on the problem of robust fault detection using analytical methods and soft computing. Taking into account the model-based approach to Fault Detection and Isolation (FDI), possible applications of analytical models, and first of all observers with unknown inputs, are considered. The main objective is to show how to employ the bounded-error approach to determine the uncertainty of soft computing models (neural networks and neuro-fuzzy networks). It is shown that based on soft computing models uncertainty defined as a confidence range for the model output, adaptive thresholds can be described. The paper contains a numerical example that illustrates the effectiveness of the proposed approach for increasing the reliability of fault detection. A comprehensive simulation study regarding the DAMADICS benchmark problem is performed in the final part.

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Authors and Affiliations

J. Korbicz
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Abstract

I n t r o d u c t i o n: Co-occurrence of physical and cognitive dysfunctions contribute to functional decline and a gradual loss of independence.

O b j e c t i v e s: The purpose of this study was to evaluate the association between global cognitive impairment and physical mobility in older adults with and without mild cognitive impairment (MCI).

Ma t e r i a l a n d Me t h o d s: A total of 800 older adults were recruited (653 with normal cognitive functioning and 147 participants with MCI). Motor performance was measured with the Timed Up and Go test (TUG) and the 6 Minute Walk Test (6MWT). Cognitive functions were evaluated using Mini- Mental State Examination (MMSE) and Addenbrooke’s Cognitive Examination (ACE-III).

R e s u l t s: ACE-III scores were associated with the TUG test performance in older adults (with and without MCI), but not with 6MWT results. The overall score in ACE-III and its subscales, i.e. a) memory and fluency in the MCI group and in the total group, and b) fluency in the control group, were associated with TUG aft er adjusting for age, sex, body mass index, medication use, depressive symptoms, hypertension, coronary artery disease and diabetes. In the case of the 6MWT test results, only the ACE-III fluency subscale scores and not the overall ACE-III score were associated with them.

C o n c l u s i o n s: Global cognitive function, verbal fluency and memory were independently associated with the TUG. ACE-III, being a more extensive testing tool than MMSE, made it possible to show the relationship between global cognition and motor skills.

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Authors and Affiliations

Anna Rajtar-Zembaty
Jakub Rajtar-Zembaty
Andrzej Sałakowski
Anna Starowicz-Filip
Anna Skalska
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Abstract

The main aim of this article is to present necessary relations between the Bible (and biblical studies) - understood as a source of theology - and theology. At the beginning the author has shown a wide historical perspective of the main problem, which is changes in the ways of understanding the Bible and theology and relations between them. Than he has said about some modern ways of resolving this difficult problem, mostly from methodological perspective. He included also the reality of the Divine Revelation, the Church and her Tradition.

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Authors and Affiliations

Ks. Marian Rusecki
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Abstract

Supplementing well recognised practical models of project and construction management, based on probabilistic and fuzzy events may make possible to transfer the weight of the change and extra orders assessment from the qualitative form to a quantitative one. This assessment, however, is naturally burdened with an immeasurable, subjective aspect. Elaboration of probability of occurrence in a construction project unforeseen building works requires application (in addition to the non-measureable, qualitative criteria) of measurable (quantitative) criteria which still appear during construction project implementation. In reimbursable engineering contracts, a random event described as an extra, supplementary building work has a random character and occurs with a specific likelihood. In lump sum contracts, on the other hand, such a random event has a fuzzy character and its occurrence is defined in a linear manner by the function of affiliation to the set of fuzzy events being identical with unforeseen events. The strive for quantitative presentation of criteria regarded by nature as qualitative and the intention to determine relations between them led to the application of the fuzzy sets theory to this issue. Their properties enable description of the unforeseen works of construction projects in an unambiguous, quantitative way.

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Authors and Affiliations

J. Konior
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Abstract

A design of the centrifugal recirculation blower as well as results of its experimental and numerical investigations are presented in this paper. The blower was designed to work in the unique test stand which is used for long-term tests of turbine flowmeters. A 1D method was used to design this blower, then experimental and numerical studies were conducted in order to verify the 1D method. A comparison of the blower pressure increase obtained from the experiment and the computations is presented. Velocity and pressure distributions from the numerical simulations in selected sections are also shown and discussed. Additional numerical studies of a shrouded rotor and a rotor with a lower tip clearance were conducted and are presented in the paper as well.

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Authors and Affiliations

Władysław Kryłłowicz
Michał Kuczkowski
Krzysztof Sobczak
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Abstract

How we speak of and write about stands, or at least it should stand, in relation what we speak of and write. If such a relation does not exist, or it is little visible for the people involved in the written or spoken message there might occur and often they do important doubts by the latter on its intention or even the assumption of bad intention. However, the existence of a clear dissonance between how we speak and write and what we speak of and write about tends many of these people addressed to perceive it as someone who breaks the norms prevailing in such speaking and writing. Those situations took place and still do often when we speak of and write about religion and religiosity without a sort of deliberation that is linked to seriousness and pompousness or even exaltation. In these remarks I do recall examples of such speaking on one side presented by libertines like M. Montaigne and Voltaire, and on the other by theologisans like St. Augustine. M. Luther and J. Tischner.

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Authors and Affiliations

Zbigniew Drozdowicz
ORCID: ORCID

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