The study presents the summary of the knowledge of energy-active segments of steel buildings adapted to obtain electrical energy (EE) and thermal energy (TE) from solar radiation, and to transport and store TE. The study shows a general concept of the design of energy-active segments, which are separated from conventional segments in the way that allows the equipment installation and replacement. Exemplary solutions for the design of energy-active segments, optimised with respect to the principle of minimum thermal strain and maximum structural capacity and reliability were given . The following options of the building covers were considered: 1) regular structure, 2) reduced structure, 3) basket structure, 4) structure with a tie, high-pitched to allow snow sliding down the roof to enhance TE and EE obtainment. The essential task described in the study is the optimal adaptation of energy-active segments in large-volume buildings for extraction, transportation and storage of energy from solar radiation.
Finite fossil fuel resources, as well as the instability of renewable energy production, make the sustainable management of energy production and consumption some of the key challenges of the 21st century. It also involves threats to the state of the natural environment, among others due to the negative impact of energy on the climate. In such a situation, one of the methods of improving the efficiency of energy management – both on the micro (dispersed energy) and macro (power system) scale, may be innovative technological solutions that enable energy storage. Their effective implementation will allow it to be collected during periods of overproduction and to be used in situations of scarcity. These challenges cannot be overestimated - modern science has a challenge to solve various types of problems related to storage, including the technology used or the control/ /management of energy storage. Heat storage technologies, on which research works are carried out regarding both storage based on a medium such as water, as well as storage using thermochemical transformations or phase-change materials. They give a wide range of applications and improve the efficiency of energy systems on both the macro and micro scale. Of course, the technological properties and economic parameters have an impact on the application of the chosen technology. The article presents a comparison of storage parameters or heat storage methods based on different materials with specification of their work parameters or operating costs.
In spite of technological, logistic and economic difficulties, interest in renewable energy sources in the world is consistently increasing. This trend is also observed in Poland, mainly due to the urgent need to tackle the problem of climate change, which is caused by the increasing concentration of gaseous pollutants in the atmosphere. The paper presents a short script of the issue of estimating renewable energy resources in Poland in the context of creating local low carbon economy plans at the level of municipalities/counties where RES sources should be taken into account. The author proposed an individual approach to estimate the potential of RES, taking the local conditions and the short characteristics of the small and medium companies sector in Poland into account. These companies have a great application potential to increase the share of renewable energies and to improve energy efficiency in their business. The actions, which are taken by the Ministry of Energy in the field of civil energy development, enhancing local energy security and the sustainable development of renewable energy resources support the development of energy clusters covering one district or five municipalities. In the article, the author presents data on the number of companies possessing a concession for generating electricity in RES installations in the power range from 40 kW to 200 kW. These companies can largely be the nucleus for creating a local cluster in which microgrids will be a key element.
The energy security of the European Union is still a concept, rather than the actual action. It was confirmed by legal regulations that give Member States the possibility of individual control of energy security. Furthermore, EU Member States can perform unilateral energy policy, which is often in the interest of the most powerful countries. The concept of energy solidarity, solidarity mechanisms of energy flows directly from the Treaty of Maastricht. This was intended to help to increase energy security, and above all, its construction at the EU level. The functioning of the European Communities and the European Union is showing that the goal of building energy security of the European Union is still in the process of creation and still remain a certain course of action. Following th energy crisis of 2009 we can observe discussion about the concept of energy union, as a way to build energy security of the European Union. Currently, its energy security is limited to the definition adopted by the European Commission and activities aimed at the development of energy infrastructure of Community interest, which contributes to improving EU energy security. The aim of this article is analyze the concept of energy union and attempt to answer the question whether it has a real chance of success, and whether the concept of the proposed shape will be effective and necessary. These questions are important because of we can observe discrepancies between the regulations, promotion of building a common energy security and the practical action of individual Member States of the European Union.
Economic development is strictly dependent on access to inexpensive and reliable energy sources based on diversified primary fuels. The strategic framework for the construction of the energy mix is defined in the Energy Policy of the State, the content of which, in terms of its mandatory elements, has been specified in the Energy Law. The task of the Energy Policy of the State is to create the shape of the future power sector, including designing the most advantageous regulatory, system and technical solutions guaranteeing the appropriate level of energy security of the country, monitoring of the system’s evolution and also designing and implementing changes aimed at the optimization of the functioning mechanisms. The vision of the development of the power system at the global level should also reflect changes in the formation of dispersed civil energy structures. Unfortunately, the results of the conducted analyses reveal existing imperfections of the data acquisition and information system, which should be used in the planning process. This issue is particularly important from the perspective of the dynamically developing concept of the energy self-sufficiency of communes and the emergence of energy clusters. The present paper describes the functioning of strategic planning in the field of the electric power system with an illustration of the improperly functioning mechanisms of information transfer in the context of the advancement of dispersed civil energy structures.
Polish energy security is currently one of the key elements affecting the national security system. Maintaining operational efficiency and the permanent modernization of both, power plants, as well as transformer stations and transmission networks is a starting point of ensuring energy security in our country. This is a significant challenge, taking into account the age of the energy critical infrastructure elements in Poland, as well as the permanent increase of the demand for electricity. This implies a systematic growth of the importance of the issue the country’s energy security. The numerous events and anomalies that accompany our everyday life, such as the storms that passed over Poland on the night of August 11–12, 2017, indicate the considerable sensitivity of the critical energy infrastructure on the impact of various negative factors. The security of Polish critical infrastructure connected with the distribution of electricity is particularly at risk. Therefore, it is desirable not only for current repairs and the modernization of the power system elements, but also for the work related to adapting the infrastructure to current and even forecasted needs, challenges and threats. In the face of the presented research results, the reconstruction of the Polish power system, as well as the implementation of innovative solutions in the production, transmission and distribution of energy seems to be unavoidable. Therefore interdisciplinary research and analyses are recommended, allowing the level security of the critical infrastructure to be increased through the best possible diagnosis of factors that may even slightly threaten this security.
The paper presents an analysis of the influence of the energy generated from renewable sources on an improvement in the energy efficiency of public utility building and households. It also presents the current state of the technologies for the production of electricity from renewable sources, as well as their share in the national power supply system. The conducted analysis concerns both micro, as well as large systems generating electricity. Systems generating power from renewable sources are gaining in popularity. With an increasing awareness in the society of the beneficial influence that renewable power generating systems have on the environment, as well as the support in form of various programs offering subsidies for the construction of new systems, power generation from renewable sources is becoming increasingly popular and common. Although the renewable energy systems are still not widely considered to be a profitable solution, systems using renewable sources of energy are positively perceived and treated as a new trend in the construction of multi or single-family residential buildings. The increasing share of the renewable energy in the national power supply system significantly reduces the demand for energy produced from conventional sources. This obviously translates into a reduced consumption of primary energy, for example, fossil fuels, and, in turn, leads to the reduced exploitation of natural resources, thus contributing to the protection of the natural environment. A reduced consumption of fossil fuels also means a significant reduction in environmental pollution during their processing into electricity or heat. Actions aiming at improving energy efficiency and reducing final energy consumption are being undertaken by many countries all over the world, and by the European Union. In 2012, the European Parliament and the Council issued Directive 2012/27/EU obliging the Member States to initiate actions aiming at a reduction in the consumption of final energy by 1.5% a year. The paper presents the current status of generation of energy from renewable sources during the last 13 years. The ways for using energy from the renewable sources to improve the energy efficiency of facilities were also discussed.
Observing the situation in the power industry it is easy to see that there are very deep changes in it. They rely primarily on moving away from conventional energy to renewable energy. This is particularly the case for energy in the European Union. Europe strives to be a forerunner in renewable technologies and a leader in the fight against global warming. The mining industry is being abolished and coal-fired power stations are being displaced by renewable energy sources. This situation is not only a result of EU directives but also of grassroots social initiatives inspired by environmental groups. The new lignite openings are being blocked, due to the lack of public acceptance, and the construction of conventional power plants. They do not help economic arguments for the development of energy based on coal, lignite, fuel that is significantly cheaper than the other, or to provide potential investors with the creation of new jobs. Also, coal investments are suspended in other regions of the world. CoalSwarm coal research shows that 2016 saw a dramatic fall in the amount of coal investment in the world. Even in China and India, where most of the coal industry has developed in recent years, about 100 investments have been suspended. The situation in the US is unclear. Although Barack Obama signed the Paris Agreement, current United States President Donal Trump has spoken out about this agreement and in numerous speeches and is eager to return to the dominant role of coal in the American economy. Poland still maintains the carbon structure of the power industry, but the Minister of Energy has announced that the new block at the Ostrołęka power plant will be the last coal-fired power plant to be built in Poland. This statement allows us to believe that there may be a return to Poland’s energy policy in the nearest future, and the long-awaited document, Poland’s energy policy until 2050, will determine the direction of change for the coming years.
The article deals with the subject of an important component of energy management, which is the performance of energy efficiency audits in companies. Using the case study analysis, the role of the energy audit was analyzed in the context of improvement of energy efficiency in selected production companies. The essence of legal requirements following from the implementation of the amended Energy Efficiency Act was presented. Specifically, problems and challenges, which refer to the method of implementation of the audit obligation in economic practice, were discussed. Furthermore, the issue of quality and usefulness (in the decision-making process) of prepared reports was raised. It was found that there were indications to claim that the obligatory energy audit of companies is not an instrument for the improvement of energy efficiency, which is always used optimally. The fault in this situation is partly attributable to the state, audit bodies and the company management. In this case, not only is the ineffective communication an issue here, but also the insufficient level of knowledge regarding energy management, as well as haste. The amendment of the Energy Efficiency Act (within just one year) imposed the necessity to conduct an energy audit on a specific group of companies. In principle, because all the entities, to which the obligation referred, had to take actions almost at the same time, numerous issues appeared. Some managers learned about the obligation to conduct the audit from companies who themselves had come out with a proposal to carry it out. This proves the lack of the proper information flow between the government administration authorities and the companies. Again, it turned out that practitioners did not keep pace with the implementation of actions, which were a consequence of numerous (and not always well thought-out) changes in the law. Haste in the fulfillment of the statutory obligation affected a high price spread of the bids sent during tenders, related to the performance of an energy audit. Bureaucratic regulations regarding tenders became another obstacle in the correct performance of the tasks. The entrepreneurs themselves, without clear guidelines on what to expect after the performed energy audit and what a report should look like, on many occasions, selected the “cheapest” bid – not always thinking too much about the qualitative consequences of such a decision. Some certifying bodies – taking advantage of an opportunity and the satisfactory combination of circumstances – offered unprofessional audit services of questionable quality. In the presented conditions, it is difficult to expect real, systemic and desirable results (economically, ecologically and socially) with regards to the energy efficiency both in the micro-, meso- and macr-economic scale. It is worth considering changes in the Energy Efficiency Act and spread the obligation to perform audits over different years according to clearly defined (in cooperation with business) criteria. If relevant actions are not taken, the situation of a temporary Eldorado on the market of energy audits will repeat in 4 years. Again, the consequence may be the poor quality and questionable usefulness of reports from energy audits of companies both at the business level and the ecological-political level. It is necessary to counteract all forms of unfair competition to interdisciplinary and specialist bodies which take actions to improve the energy efficiency of organisations. The creation of appropriate business conditions will have a positive impact on the improvement of energy efficiency. In this context, it is necessary to take actions, which enable the optimization of both the process of the implementation of obligatory legal regulations and voluntary (industry) norms and standards.
Pollution, climate change and energy security are significant problems. Climate-disrupting fossil fuels are being replaced by clean and non-depletable sources of energy. It requires major changes to energy infrastructures and strong support for promotion of the use of energy from renewable sources. Renewable energy is emerging as a driver of inclusive economic growth and reinforcing energy security. Public entities have to promote renewable energy development by implementing cost-effective national support schemes. By acting at national-level, several barriers to public and private investments could be tackled, addressing the lack of coordination between various authorising bodies at national level and stimulatng the administrative capacity to implement energy projects. It should be effective in promoting transparency for investors and others economic operators. In Poland there is a lack of regulatory policies creating incentives for decentralised energy. Market-based support schemes are still needed for small-scale self-consumption system. Currently operating solutions have been shown in the contrast of the ones applied abroad. The development of clean energy technologies depends on many factors. The author identified few most important ones, mainly financial, regulatory issues, social, environmental and characterized them in this work. The article presents the recommendations of regulatory framework and some proposals for energy cluster based policy’s tools, the introduction of which would significantly facilitate the wider renewable energy uses in Poland.
An analysis of the power system functioning and the behaviors of the energy market participants allows the trends taking place within years to be identified, including these associated with the evolution of the electric energy and power demand profiles. The problems of balancing the peak power demand are of both a short and long term nature, which implies the need for changes in the electricity generation sector. Apart from the existing “silo-type” generation units, the construction of distributed energy sources implemented in the civic formula in the framework of self-sufficient energy communes and energy clusters is becoming increasingly important. Support for these programs is realized both at the legislative level, as well as within dedicated competitions and ministerial activities. The financial support carried out by the National Fund for Environmental Protection and Water Management and the Regional Operational Programs is also noticeable. One of the activities aimed at spreading the idea of clustering was the competition for certified energy clusters, conducted by the Ministry of Energy. The goal of the contest was the promotion and development of the distributed energy sector, which could be used for the improvement of energy security in the local manner and constitute a basis for the knowledge necessary in planning and developing the state’s energy policy. The paper presents a synthetic analysis of the results of the competition for a certified energy cluster from the perspective of planning and operational needs related to the functioning of the power system. Further, the information about the investment plans of new generation capacities, including their breakdown with respect to type, achievable power and costs has been provided. Also, the balancing of the demand for electric energy by own generation within the energy clusters has been characterized for three time perspectives
Coal in Poland is an available conventional fuel providing energy security and independence of the country. Therefore, conventional energy generation should be based on coal with the optimal development of renewable energy sources. Such a solution secures the energy supply based on coal and the independence of political and economic turmoil of global markets. Polish coal reserves can secure the energy supply for decades. Coal will surely be important for energy security in the future despite the growing share of oil and gas in energy mix. The development of renewable power generation will be possible with the conventional energy generation offsetting volatile renewable power generation as Poland’s climate doesn’t allow for the stable and effective use of renewable energy sources. Considering the policy of the European Union with respect to emission reductions of greenhouse gasses and general trends as reflected in the Paris agreement in 2016, as a country we will be forced to increase renewable energy production in our energy mix. However, this process cannot impact the energy security of the country and stability and the uninterrupted supply of energy to consumers. Therefore seeking the compromise with the current energy mix in Poland is the best way to its gradual change with the simultaneous conservation of each of the sources of energy. It’s obvious that Poland can not be lonely energy island in Europe and in the world, which increasingly develops distributed energy and/ renewable technologies as well as energy storage ones. One can notice that without renewable generation and the reduction of coal’s share in country’s energy mix we will become the importer of electricity with raising energy dependence.
The paper presents brown coal as one of the two basic domestic energy raw materials apart from hard coal. Historically, the use of brown coal in Poland is primarily fuel for the power plants. It was used for the production of lignite briquettes in small quantities and as fuel for local boiler houses and as an addition to the production of fertilizers (Konin and Sieniawa). At present, after changes in the case of the quality of fuels used in local boiler plants, brown coal remains as a fuel for the power plants in almost 100%. Currently, the brown coal industry produces about 35% of the cheapest electricity. The cost of electricity production is more than 30% lower than the second basic fuel – hard coal. The existing fuel and energy complexes using brown coal, with the Bełchatów complex at the forefront, are now an important guarantor of Poland’s energy security. In contrast to the other fuels such as: oil, natural gas or hard coal, the cost of electricity production from brown coal is predictable in the long term and almost insensitive to fluctuations in global commodity and currency markets. Its exploitation is carried out using the high technological solutions and respecting all environmental protection requirements, both in the area of coal extraction and electricity generation. Importantly, the fuel and energy complexes using brown coal showed a positive profitability so far and generated surpluses enabling the financing of maintenance and development investments, also in other energy segments. In particular, the sector did not require and has yet not benefited from public aid in the form of, for example, subsidies or tax concessions. Polish brown coal mining has all the attributes necessary for long-term development to ensure the country’s energy security. The document which is a road map for the brown coal industry is the Program for the Brown Coal Mining Sector in Poland adopted by the Council of Ministers on May 30, 2018. The Program covers the years 2018–2030 with a perspective up to 2050 and presents the development directions of the brown coal mining sector in Poland together with the objectives and actions necessary to achieve them. The Program presents a strategy for the development of brown coal mining in Poland in the first half of the 21st century. Possible scenarios have developed in active mining and energy basins as well as in new regions with significant resources of this mineral. This is to enable the most efficient use of deposits in the Złoczew and Konin regions as well as the Gubin and Legnica brown coal basins, and then deposits located in the Rawicz region (Oczkowice) as well as other prospective areas that may eventually replace the existing active mining and energy areas. This will allow power plants to continue to produce inexpensive and clean electricity, using the latest global solutions in the field of clean coal technologies.
The energy efficiency of photovoltaic modules is one of the most important aspects in energetic and economic aspects of the project related to system installations. The efficiency of modules and the electricity produced by photovoltaic conversion in solar modules is affected by many factors, both internal, related to the module structure itself and its technical and external factors related to the energy infrastructure, which includes: cabling, inverters, climate conditions prevailing at the micro-installation location and the orientation and angle of inclination of the solar modules. The installation of photovoltaic modules should be preceded by an energy efficiency analysis, which will help to indicate the optimal solution adapted to the given conditions. The article presents a comparative analysis of the amount of energy produced under real and simulated conditions. Analyzes were made on the basis of research carried out in the Wind and Solar Energy Laboratory located at the AGH University of Science and Technology, data from solar irradiation data-bases and computer software for estimating energy resources. The study examined the correlation of the solar irradiation on the modules and the amount of electricity generated in the photovoltaic module. The electricity produced by the module was compared under real conditions and simulated based on two sources of data. The comparison and analysis of the amount of energy of the module were also made, taking simulated different angles of the module’s inclination into account.
The aim of the article is to discuss and assess the diversification of renewable energy sources consumption in European Union member states. The time scope covers 2005 and 2015. The data comes from Eurostat. The analysis was based on synthetic indicators – using a non-standard method. Synthetic indicators were assessed based on three simple features such as: the share of renewable energy in energy consumption in 2015, the difference between the share of renewable energy in energy consumption in 2015 and in 2005 (in percentage points), deficit/surplus in the 2020 target reached in 2015 (in percentage points). The European Union member states were divided into four diversified group in terms of renewable energy sources consumption (first class – a very high level, second class – quite a high level, third class – quite a low level, fourth class – a very low level). Then the divided groups were analyzed according to the share of renewable energy sources in the primary production of renewable energy and the consumption of individual renewable energy sources. During the research period renewable energy consumption increased in the European Union, but individual member states are characterized by a diverse situation. The type of energy used depends largely on national resources. The countries of Northern Europe are characterized by a greater share of renewable energy sources in consumption. Biomass is the most popular renewable source of energy in the European Union. Depending on the conditions of individual countries – it is agricultural and forest biomass.
The primary aim of this paper was to assess the development of prosumer energy sector in Poland. In the first point, the basic notions connected with prosumer energy (micro-installation, prosumer) were discussed on the basis of Law of Renewable Energy Sources of February 20, 2015 (Journal of Laws, item 478, as amended) and the main aspects of the European Union energy policy where presented in the context of the development of the prosumer energy sector. In this part of the study, numerous benefits for the Polish economy and consumers of electrical energy, connected with the expansion of prosumer energy sector, were presented. On the other hand, many obstacles which stall this sector in Poland were noticed. In the second point the most important regulations from the Law of Renewable Energy Sources of February 20, 2015 were analyzed (In the second point the most important regulations from the Law of Renewable Energy Sources of February 20, 2015 (hereinafter: the RES act) were analyzed). On the basis of this legal act, the so called “rebate system”, which is currently used in Poland to support prosumers of electrical energy, was described. Moreover, many legal and administrative simplifications implemented by the RES act were indicated. The analytical approach to the RES Act in this study resulted in the detection of many regulations in this legal act which may have an adverse impact on the development of the prosumer energy sector in Poland. In the third point, programs co-financed by the Polish government or the European Union, which financially support the purchase and installation of energy technologies using RES, were described. Statistical data connected with the prosumer energy sector in Poland was presented in the fourth point of this paper. On the basis thereof, the authors attempted to find the correlation between the number of prosumers and the share of the amount of electrical energy from renewable energy sources in gross electrical energy consumption. In the fifth point issues connected with energy technologies used in the Polish prosumer energy sector were discussed. Moreover, this point focuses on the great popularity of photovoltaic modules among Polish prosumers and results in the reluctance of Polish prosumers to install wind microturbines and small hydroelectric power plants.
Increasing the share of energy production from renewable sources (RES) plays a key role in the sustainable and more competitive development of the energy sector. Among the renewable energy sources, the greatest increase can be observed in the case of solar and wind power generation. It should be noted that RES are an increasingly important elements of the power systems and that their share in energy production will continue to rise. On the other hand the development of variable generation sources (wind and solar energy) poses a serious challenge for power systems as operators of unconventional power plants are unable to provide information about the forecasted production level and the energy generated in a given period is sometimes higher than the demand for energy in all of the power systems. Therefore, with the development of RES, a considerable amount of the generated energy is wasted. The solution is energy storage, which makes it possible to improve the management of power systems. The objective of this article is to present the concept of electricity storage in the form of the chemical energy of hydrogen (Power to Gas) in order to improve the functioning of the power system in Poland. The expected growth in the installed capacity of wind power plants will result in more periods in which excess energy will be produced. In order to avoid wasting large amounts of energy, the introduction of storage systems is necessary. An analysis of the development of wind power plants demonstrates that the Power to Gas concept can be developed in Poland, as indicated by the estimated installed capacity and the potential amount of energy to be generated. In view of the above, the excess electricity will be available for storage in the form of chemical energy of hydrogen, which
The implementation of micro scale combined heat and power systems is one of the ways to improve the energy security of consumers. In fact, there are many available large and medium scale cogeneration units, which operate according to the Rankine Cycle. Due to European Union demands in the field of using renewable energy sources and increasing energy efficiency result in the importance of additionally developing systems dedicated for use in residential buildings, farms, schools and other facilities. This paper shows the concept of introducing thermoelectric generators into typical wood stoves: steel plate wood stoves and accumulative wood stoves. Electricity generated in thermoelectric generators (there were studies on both three market available units and a prototypical unit developed by the authors) may be firstly consumed by the system (to power controller, actuators, fans, pumps, etc.). Additional power (if available) may be stored in batteries and then used to power home appliances (light, small electronics and others). It should be noted that commercially available thermoelectric generators are not matched for domestic heating devices – the main problems are connected with an insufficient heat flux transmitted from the stove to the hot side of the generator (caused e.g. by the non -homogeneous temperature distribution of the surface and bad contact between the stove and the generator) and inefficient cooling. To ensure the high efficiency of micro cogeneration systems, developing a dedicated construction both of the generator and the heat source is necessary.
Hybrid Renewable Energy Systems connected to the traditional power suppliers are an interesting technological solution in the field of energy engineering and the integration of renewable systems with other energy systems can significantly increase in energy reliability. In this paper, an analysis and optimization of the hybrid energy system, which uses photovoltaic modules and wind turbines components connected to the grid, is presented. The system components are optimized using two objectives criteria: economic and environmental. The optimization has been performed based on the experimental data acquired for the whole year. Results showed the optimal configuration for the hybrid system based on economical objective, that presents the best compromise between the number of components and total efficiency. This achieved the lowest cost of energy but with relatively high CO2 emissions, while environmental objective results with lower CO2 emissions and higher cost of energy and presents the best compromise between the number of components and system net present cost. It has been shown that a hybrid system can be optimized in such a way that CO2 emission is maximally reduced and – separately – in terms of reducing the cost. However, the study shows that these two criteria cannot be optimized at the same time. Reducing the system cost increase CO2 emission and enhancing ecological effect makes the system cost larger. However, depends on strategies, a balance between different optimization criteria can be found. Regardless of the strategy used economic criteria – which also indirect takes environmental aspects as a cost of penalties – should be considered as a major criterion of optimization while the other objectives including environmental objectives are less important.
Natural gas plays a significant role in the energy structure of many world economies. Many of them are highly dependent on domestic resources exploitation, other on its deliveries from non-domestic directions. In Poland its importance was relatively low, but in recent years we can observe an increase of interest in this raw material. The aim of the paper is to present the role of natural gas as a primary energy carrier and to determine its impact on the sustainable development and energy security of Poland. The role of gas in the European Union restrictions and development of the domestic economy is also a point. Theoretical deliberations are focused on the most important features of the Polish natural gas market. The article presents the most important national regulations concerning the development of the gas sector in Poland. The amount of natural gas resources are shown as well as indigenous production of the fuel and imports, including the directions from which natural gas is imported. Both political and geographical aspects of the directions of natural gas acquisition are discussed. The level and potential abilities of the diversification of the natural gas supply are discussed. The importance of gas storages in underground gas repositories is underlined. The authors point to the increase in the diversification of raw materials in the structure of electricity, heat production and the transition to pro-ecological fuels.
Assumptions of the major political and legal documents of the European Union, dedicated to energy efficiency and energy performance of buildings provide the Member States with relevant instruments supporting improvement of the ambient air qualityby dissemination of measures reducing energy demand and promotion of renewable energysources. Mainstreaming EU legislation into national regulations constitutes initial stage of the long term process of supporting implementation of energy efficiency measures. Experience in the improvement of energy performance of the residential buildings revealslimited efficiency of the measures implemented up to date, which results in significantair pollution of Polish cities. The national Action Plans had adopted a limited scope of recommendations included in the EU directives, hence the process meets significant challenges.The article describes adaptation of the relevant EU directives as well as the National Urban Policy in terms of the potential to effectively address faced challenges.
The role and importance of energy security increases with the development of civilization, whose inherent element has become the demand for energy and its carriers. The article discusses the issue of cooperation in the field of energy security in Central Europe at the moment of finishing work on the North-South Corridor, which changes the existing gas architecture in the region. In order to better understand the situation in the region, the energy systems of the Visegrad Group countries, identical to the Central European region, have been analysed, according to the definition of the World Bank and OECD. Considering the historical and geopolitical connections of the Visegrad Group’s fate, it is important to create a common gas market. The physical interconnection of gas systems greatly increases energy security in this region. Moreover, thanks to the construction of LNG terminals in Poland and Croatia, it will be possible to diversify not only the routes, but also the sources of supply of this important raw material.
In literature as well as in the university debate, we can observe the increase of interest regarding converting agricultural residues into energy. Furthermore, the energy and climate policies have encouraged the development of biogas plants for energy production. One of the most significant reasons of this escalation is that this technology may be both convenient and beneficial. The produced biogas is not only supposed to cover the energy demand like heat and electricity, the resulting digestate has the prospect of a beneficial fertilizer and can thereby influence the energy management plans. This technology is widely introduced to countries, which have large income from agriculture. Not only does this reduce the use of industrial fertilizers, but also finds use for agricultural residues. One of the countries of this type is Vietnam, which is the fifth largest exporter of rice in the world. Over 55% of greenhouse gas emission in Vietnam comes from agriculture. Using innovative technologies such as biogas, may decrease this value in near future. It may also contribute to more sustainable agriculture by decreasing traditional fields burning after the harvesting period. The goal of this research paper is to estimate the possible production of biogas from rice straw to cover the energy demand of the rice mill. Four possible scenarios have been considered in this paper, the present situation and where electricity, energy or both were covered by biogas from agricultural residues. An attempt was made to answer the question whether the amount of biogas produced from agricultural residues is enough for both: electricity and energy supply, for the rice mill. If not, how much rice straw must be delivered from other sources, from which rice is not delivered to the rice mill. The base of the assumptions during the estimation of various values were statistics from FAO and other organizations, secondary sources and data from the existing rice mill in Hậu Mỹ Bắc B in Mekong delta in Vietnam.
The study presents the results of theoretical investigations into lateral torsional buckling (LTB) of bi-symmetric I-beams, elastically restrained against warping at supports. Beam loading schemes commonly used in practice are taken into account. The whole range of stiffness of the support joints, from free warping to warping fully restrained, is considered. To determine the critical moment, the energy method is used. The function of the beam twist angle is described with power polynomials that have simple physical interpretation. Computer programs written in symbolic language for numerical analysis are developed. General approximation formulas are devised. Detailed calculations are performed for beams with end-plate joints. Critical moments determined with programs and approximation formulas are compared with the results obtained by other researchers and with those produced by FEM. Very good accuracy of results is obtained.