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.
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.
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.
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.
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 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
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 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.
Intensive modernization and reconstruction of the energy sector takes place throughout the world. The EU climate and energy policy will have a huge impact on the development of the energy sector in the coming years. The European Union has adopted ambitious goals of transforming towards a low-carbon economy and the integration of the energy market. In June 2015, the G7 countries announced that they will move away from coal fired energy generation. Germany, which has adopted one of the most ambitious energy transformation programs among all industrialized countries, is leading these transformations. The long-term strategy, which has been implemented for many years, allowed for planning the fundamental transformation of the energy sector; after the Fukushima Daiichi nuclear disaster, Germany opted for a total withdrawal from nuclear energy and coal in favor of renewable energy. The German energy transformation is mainly based on wind and solar energy. Germany is the fifth economic power in the world and the largest economy in Europe. Therefore, the German energy policy affects the energy policy of the neighboring countries. The article presents the main assumptions of the German energy policy (referred to as Energiewende). It also presents the impact of changes in the German energy sector on the development of energy systems in selected European countries.
Article investigates the issue of terms of trade in energy products. The goal of this paper is to check how the terms of trade in energy fluctuate. The analysis is carried out on the example of Poland as a country which offers an interesting energy imports and exports structure. The time horizon covers the period from 2005–2015 and is extended to give the broader picture of the phenomenon wherever possible. In the research, the author uses the barter terms of trade concept. The paper has been organized in four sections. The study opens with introductory remarks presenting Polish energy situation, which is followed by a description of the terms of trade concept on the grounds of international economics. The results of the research are discussed in section three which ends with a summary and conclusions. The last part includes an additional description of study constraints and suggestions the next research steps. The statistical data used in the paper comes from national databases of the Polish Central Statistical Office and international sources such as the Organisation for Economic Cooperation and Development. Additional information on energy prices was derived from recognized branch sources such as BP Statistical Review of World Energy.
Until the early 1990s, the domestic power industry was a natural monopoly. This was caused by the specificity of the operation of the electricity transmission and distribution sub sectors, technical challenges of coordinating the operation of generating units and transmission networks, requirements regarding long-term forecasting of the industry development, and returns to scale. In view of the above, the objective of the presented paper is to assess the economic situation of energy companies operating in a competitive electricity market. The article analyses the main areas of activity of the energy companies, i.e.: the areas of production, transmission, distribution, and sales. In addition, the market shares of the various energy companies, in terms of generating capacity and the amount of the energy produced, were analyzed. Furthermore, the technical and economic situation of enterprises operating in the power sector was also subjected to analysis. The mentioned analysis has revealed that the profit received from the main activity of the enterprises (i.e. the sale of electricity) has decreased in recent years. What is more, the energy sector must adapt to legal and regulatory changes related to the intensification of the decarbonization policy pursued by the European Commission. Therefore, national energy should focus on developing skills in the areas of innovation, such as: electro mobility, energy storage, energy management, etc.
Poland is now faced with the task of developing a long-term energy policy for decades to come, a strategy capable of reconciling the security of power supplies as well as effective economic processes, ensuring adequate standards of environmental protection. The process in which fossil fuels are converted into energy carriers of choice is accompanied by the emission of various gas substances which escape into the environment. Later on, those substances accumulate in the atmosphere as greenhouse gases affecting the Earth’s radiation balance – the greenhouse effect. Upsetting the balance between emission levels of those gases and the capacity to convert them in the atmosphere is the reason for climate changes. Sustainable development indices constitute a monitoring tool which makes it possible to create a statistical image of a country from the perspective of a new development paradigm. The most important feature of this index is the capability of comparing values, enabling to determine the position of a given object with reference to other objects. The article analyses 8 indexes of sustainable development in terms of using biomass for power generation purposes. The analysis was performed to include three social order indices, two economic indices and one environmental order index. It was concluded that the use of biomass in power generation can reduce the emission of greenhouse gasses significantly at several stages: the emission can be eliminated from the biological process of biomass conversion, storage and it can also be reduced during transportation.
The development of electromobility is a challenge for the power system in both technical and economic-market terms. As of today, there are no analyses to determine the power necessary to supply the planned infrastructure and to estimate the incentives and economic benefits resulting from the modification of the settlement method. The document determining the legal regulations and the obligation to build vehicle charging stations for specific municipalities is the Act on Electromobility and Alternative Fuels. This act estimates that the development of electromobility, due to the specifics including not only individual vehicles, will take place in certain areas. The places which in the first stage will be dedicated to the potential implementation of the concept of electromobility will be municipalities covering large agglomerations. In addition, due to the local aspect, the development of electromobility may take place in the areas of energy clusters’ initiatives, which, using the policy of increasing energy awareness, are aimed at energy production from local renewable energy resources. The planned development of electromobility assumes a systematic increase in the number of electric cars caused by the introduction of support systems. The dynamization of this sector will cause an increase in the demand for electricity. Due to power system reasons, an important factor determining the level of energy consumption depending on the time of day may be an appropriate shape of the pricing for the charging service. Appropriate price list stimulation can affect the behavior of recipients, causing the charging of cars in the off-peak of electricity demand. The aim of the article is to characterize the scale of the phenomenon of electromobility in the context of the emergence of a charging points infrastructure along with the possibility of price-setting stimulation affecting the profile of energy demand. It is also important to consider the challenges and responsibilities of municipalities and energy clusters from the perspective of introducing electromobility.
This publication presents an assessment of the economic efficiency of a hypothetical installation for the gasification of the municipal and industrial waste for the production of syngas used subsequently for the production of energy or chemical products. The first part of the work presents an example of a technological system for the energo-chemical processing of coal mud and municipal waste, based on the gasification process using a fluidized bed reactor. A hypothetical installation consists of two main blocks: a fuel preparation unit and a gasification unit. In the fuel preparation installation, reception operations take place, storage, and then grinding, mixing, drying and transporting fuel to the gasification unit. In the gasification installation, fuel gasification, oxygen production, cooling and purification of raw process gas and ash treatment are carried out. The following key assumptions regarding the gasification process, as well as the capital expenditures and operating costs related to the process, were estimated. Consequently, based on the method of discounted cash flows, the unit cost of generating energy contained in the synthesis gas (cost of energy, COE) was determined and the results were interpreted. In order to obtain an acceptable efficiency of the gasification process for waste fuels for the production of alternative fuel (process gas), it is necessary to supplement the mixture of waste coal and coal mud with the RDF. In this case, the unit cost of fuel measured by the PLN/GJ index is lower than in the case of hard coal and comparable with brown coal. The use of coal mud for the production of process gas in an economically efficient way is possible only in the case of changes in the legal system allowing for charging fees for the utilization of industrial waste – coal mud.
The article presents a synthetic analysis of the crude oil market in Poland. As of today, this safety is provided mainly on the basis of native lignite and hard coal resources. However, the analysis of the hard coal market conducted by the authors indicates that the carried out mining restructuring (among others) led to an excessive reduction of mining volume and employment level in the hard coal mining sector. This led to a precedent situation when Poland became an importer of this energy carrier. In addition, the European Union’s requirements for greenhouse gas emissions must be taken into account. In connection with the above, it is necessary to search for new energy sources or technologies that enable hard coal to meet the requirements. It is possible to apply the so-called clean coal technologies that allow the greenhouse gas emissions generated during coal combustion to be reduced. As of today, they are not used on a mass scale, because the use of this type of technology involves additional financial expenses. However, taking into account that technologies have been growing faster and faster, are modernized in a shorter time, making a breakthrough discovery took hundreds of years, now it is often a few months, clean coal technologies can become the optimal solution in the near future. It is also necessary to diversify the sources of obtaining imported energy carriers. The article describes coal and crude oil in terms of their mutual substitution. The article is a continuation of research conducted by the authors. Previous publications presented considerations on analogous topics related to natural gas and renewable energy sources. The crude oil market in Poland was analyzed and forecasts for oil extraction and the demand in the world and Poland by 2023 were presented. The SARIMA model was also created. The model made it possible to obtain oil an prices forecast.
Humidity is probably the most important abiotic factor influencing life cycles, distribution, survival, and population dynamics of stored product pests. Although most of these pests can complete their life cycles in any given relative humidity, their prolonged development time, as well as decreased emergence rate and fecundity, have been well documented in several previous studies. In the present study, we evaluated the changes in energetic substances (lipids, soluble carbohydrates, glycogen, and proteins) accumulated in different life stages of larvae and adults of Tribolium castaneum in response to different relative humidity levels (5, 12, 22, 30, 45, and 65%). The results showed that young larvae were more susceptible to low relative humidity levels and desiccation stress. Larvae tended to accumulate higher proportions of lipids during earlier stages while their energy content shifted towards proteins with an increase in their age. Adult beetles experienced a significant decrease in their protein content immediately after they initiated reproduction. The importance of these fluctuations in the biology of the red flour beetles was discussed in detail.
The present work focuses on a first study for a piezoelectric harvesting system, finalized to the obtaining of electrical energy from the kinetic energy of rainy precipitation, a renewable energy source not really considered until now. The system, after the realization, can be collocated on the roof of an house, configuring a “Piezo Roof Harvesting System”. After presenting a state of art of the harvesting systems from environmental energy, linked to vibrations, using piezoelectric structures, and of piezoelectric harvesting systems functioning with rain, the authors propose an analysis of the fundamental features of rainy precipitations for the definition of the harvesting system. Then, four key patterns for the realization of a piezoelectric energy harvesting system are discussed and analysed, arriving to the choice of a cantilever beam scheme, in which the piezoelectric material works in 31 mode. An electro-mechanical model for the simulation of performance of the unit for the energetic conversion, composed of three blocks, is proposed. The model is used for a simulation campaign to perform the final choice of the more suitable piezoelectric unit, available on the market, which will be adopted for the realization of the “Piezo Roof Harvesting System”.
The article describes selected issues falling within the scope of the technical analysis of a detached building’s heating system with a direct evaporation ground source heat pump installation. This paper covers the characteristics of modernized facility as well as calculations to determine the heat demand. What is more, the article describes the manner in which heat pumps shall be selected, its installation components as well as the receiving installation.
Improving energy efficiency is key to moving toward sustainable development. It contributes to the reduction of energy consumption and carbon emissions, as well as to climate change mitigation. Indicators of energy efficiency play an important role in this field because their improvement is targeted by policy makers. Indicators based on the ratio between energy consumption and gross domestic product (GDP) are currently used by multiple key organizations, including Eurostat and the World Bank, as the main energy efficiency indicators. This study examines the most widely used indicators and identifies their deficiencies. Over the last decades, these indicators tend to show a continuous strong improvement, signifying positive progress toward energy efficiency, even in cases when the physical consumption of energy has increased significantly. This phenomenon is based on GDP adjustment. The energy intensity of economies, used currently to measure energy efficiency, masks problems and has led to the green labeling of wealthier economies. An analysis of energy efficiencies reported for multiple countries and the structure of their energy spending shows that the reported values are counterproductive for comparing economies in the context of environmental protection. The indicators sanction economies with low energy consumption and low or moderate GDP. The economies belonging to the group of the largest energy spenders per capita are labeled highly efficient because of GDP adjustment. Decision makers are therefore prompted to focus on GDP growth even at the cost of a major increase in energy consumption. An additional problem in the indicators is that they do not properly model international trade. The responsibility for energy spending is shifted toward the producers of energy-intensive goods and services. Energy intensity is a useful indicator to measure the resistance of an economy to the volatilities of energy prices. However, the challenges in the fields of environmental pollution and climate change are related to physical processes and energy consumption rather than to changes in the GDP or the monetary valuation of products and services. Indicators measuring energy efficiency as GDP per unit of energy use are inadequate and misleading as principal tools to measure energy efficiency.
The Energy Law of April 10, 1997 initiated changes in the energy market in Poland. Actions taken on the basis of this law were aimed at the modernization and development of the power sector. Organizational and legal changes causing the development of distributed generation, thus increasing the level of market competition have been introduced. The care for high quality of customer service, including the protection of vulnerable customers, environmental protection, growing share of renewable energy and emission reduction requirements have become a reality. It seems, therefore, that it is necessary for the Polish energy sector to undergo permanent modernization, to develop the production and industrial infrastructure and to develop modern conventional technologies by way of implementing innovations in the field of energy companies. The author of the paper argues that it is indispensable to make a broadly understood transfer of knowledge and technology to the energy sector on the basis of a knowledge-based economy. This also applies to energy clusters, which currently constitute a platform for cooperation: entrepreneurs, scientific-research units, and public authorities. The functioning of these entities is an important catalyst for the transfer of knowledge and technologies. Their regional nature boosts competitiveness of the involved enterprises, and is a natural way of transferring knowledge to the energy market.