This article presents an investigation of solar power plants’ economic efficiency in the case of energy prosumers. The economic effect of the development of solar energy, the environmental effect of the transition to green energy and the social effect due to lower electricity costs and investment growth from the use of photovoltaic installations (PVI) have been proven. The level of annual savings in PVI due to changes in production and own consumption of electricity are determined. Through use of factor analysis, the grouping method, the method of generalizing indicators, quantitative data collection for solar PV systems and the matrix method, the two main hypotheses were proven: (i) solar energy production should be stimulated by a sound state tariff policy; (ii) prosumers as players of the electricity market should be considered in the tariff policy. It is revealed that at current interest rates, PVI operational activity is subject to more complex factors, and the main one becomes economic, namely considering the economy of consumers, the level of taxation or grants of PVI activities, as well as productivity and the real state of technical condition of devices. The provided research develops the theoretical and empirical basis for the state policy of solar electricity usage with consideration to the peculiarities of its production and consumption. The process of production and consumption of electricity in PVI is not characterized by uniformity, which is derived from a number of factors, primarily from natural and climatic conditions. It also depends on the technical characteristics of the devices.

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.

The inevitability and successive implementation of the elements of the European Union (EU) energy policy and the freedom of achieving the goals left in this regard for the member states should translate into actions taking the specificity of local markets into account, in order to carry out liberalization processes in a harmonious manner. In 2016, the European Commission published a package of guidance documents “Clean Energy for All Europeans” in the perspective of 2030, also known as the Winter Package. The recommendations contained in some of the documents assume the continuation of integration of markets in the national and regional dimension, setting ambitious targets in the field of decarbonization, the increase of energy efficiency and the increase of Renewable Energy Sources (RES) share in the energy balance of EU countries. The short time to carry out a thorough reconstruction of the energy-generating sector forces to seek solutions that are in line with the European Community recommendations and, at the same time, do not constitute an excessive burden for the national economy and legal order. One of the activities is to use the potential of micro-networks of local communities striving for energy independence based on their own energy sources and to create regulations enabling the neighborly exchange of energy. This mechanism works in the form of pilot projects in many locations around the world (Sonnen Group; Power Ledger). The paper presents the concept of functional and analytical assumptions for an exemplary structure of neighboring prosumers along with the presentation of simulation results based on real generation and consumption profiles and the presentation of investment profitability indicators for the proposed functional model.

The energy sector, particularly that related to renewable energy, is growing rapidly. The analysis of factors influencing the production of electricity from solar radiation is important in terms of the ever-increasing number of photovoltaic (PV) installations. In Poland, the vast majority of installed PV capacity belongs to prosumers, so a comparative analysis was conducted for two domestic installations, one in southern Poland and the other located in central Poland. Operating conditions were compared, specifically with regard to irradiance, outdoor temperature and the calculated temperature of photovoltaic cells. The specific yield was then compared in daily, monthly and annual statements. The effects of the previously mentioned parameters on the energy yields of the two installations were considered. The installation in southern Poland in 2022 produced 5,136.6 kWh, which corresponds to a specific yield of 1,019.17 kWh/kWp, while the energy production of the installation in central Poland was 4,248.9 kWh, which corresponds to a specific yield of 965.67 kWh/kWp.

The paper presents the idea of a prosumer energy cloud as a new service dedicated to electricity prosumers. The implementation of the cloud should generate a number of benefits in the following areas: settlements between prosumer and electricity supplier, the development of distributed energy sources in microprocessors and the development of e-mobility. From the prosumer point of view, the proposed idea of a prosumer cloud of energy is dedicated to the virtual storage of energy excess generated in the micro-installation. Physical energy storage in the cloud means recording the volume of electricity introduced into the electricity system from the prosumer’s microprocessors. It is assumed that the energy equivalent to the volume registered in the prosumer cloud can be used at any time at any point in the network infrastructure of the National Power System. Any point of network infrastructure shall be understood as any locally located point of connection of an electricity consumer provided with access authorization. From the point of view of the power grid operators, the idea of a prosumer energy cloud is a conceptual proposition of a service dedicated to the new model of the power system functioning, taking future conditions concerning the significant development of prosumer energy and e-mobility into account. In this concept, electricity would be treated as a commodity only to partial physical storage and above all to trade. In this model a key aspect would be virtual energy storage, that is, the commercial provision by the cloud operator (trading company) of any use of the electricity portfolio by its suppliers. It should be stressed, however, that in the prosumer’s energy cloud functioning, a significant factor would be the cost of guarantees of the use of energy by prosumers at any time and point of connection to the network. This results in the need of taking the presence of certain market risks, both volumetric and cost incurred by clouds operator, which can be minimized by passing a portion of the accumulated volume of generated energy to the cloud operator into account. It should be emphasized that this article presents the first phase of the development of the concept of prosumer energy cloud. However, it is planned to be expanded by the following stages, which include the possibility of controlling and supervising the operation of prosumer installations such as: sources, receivers and physical energy stores, e.g. home energy storage or batteries installed in electric vehicles. Ultimately, it is assumed that the proposed prosumer energy cloud will be outside of the storage of energy (virtual and partly physical) and that aggregation of prosumer resources will create new possibilities for their use to provide a variety of regulatory services, including system ones.

This paper presents the main dilemma of development of the Polish energy sector on the 20th anniversary of the first liberalization directive of the European Union, which created the energy market. The situation in the Polish energy sector based on fossil fuels, its transformation into lower emission one is closely connected to the process of restructuring and further development of the mining sector. On the other hand, we are witnessing the development of RES, household installations producing electricity with storage and the electrification of public transport. The investments in new, large scale fossil fuel fired power plants are very expensive and not economically proven when electricity prices are low. Until the new direction of investment in energy sector will be decided, the option of the lasting of the operating existing power units seems to be a good proposal. Is the thesis: “The energy security of Poland should be fully based on indigenous sources, generation and distribution assets, delivering electricity to end users. Ensuring competitive energy prices to the economy and households, the market should be fully open to producers and consumers, including chip electricity arising from the European single market” the right assumption for the Polish energy policy?

This article studies the implications of the Fourth Energy Package and relevant EU Directives for households and explores their potential benefits in Ukraine. Understanding the effects of energy policies on the residential sector is crucial for promoting sustainability amidst global energy and climate challenges. Methods of descriptive legal studies and investment analysis are used to examine the primary EU legislation on renewable energy communities and citizens’ groups, focusing on their applicability to homes and renewable energy cooperatives. The analysis of Ukraine’s experiences with the adoption of green power and incentives have revealed challenges for small solar home installations operating without the feed-in tariff. Introducing net-billing makes projects unfeasible without such a tariff, and even selling electricity through aggregators on the intraday market does not help. Consequently, the payback period for small installations with batteries becomes unreasonably long (exceeding twenty-five years), while larger facilities have shorter payback termsolytechnic Institute, Ukraine (fifteen to seventeen years). These findings highlight the need for careful consideration of household green-power policies. Implementing the Fourth Energy Package in Ukraine requires measures to address the financial feasibility of small solar installations, particularly those lacking feed-in tariff support. Expanding legislative provisions to include consumers of green power, especially those in multi-apartment buildings, can enhance their participation in the electricity producers’ market. Moreover, raising household electricity prices may be necessary to support sustainable energy practices. Overall, this study underscores the importance of evidence-based policymaking for successful power transitions in homes and the broader energy sector.

Renewable energy aims at reducing greenhouse emissions, supplying the growing demand for electricity, and diminishing consumption of fossil fuels – these are the basic elements of the New Green Deal, heading towards carbon neutrality. However, renewables have negative impacts on the electricity network’s operation, leading to reduced power system stability.

Nowadays the demand for renewable energy sources is constantly growing. There are several reasons of such state, including requirements for energy-efficient new buildings and reduction of greenhouse gas emissions. An exemplary solution that may help to reduce “traditional” primary energy consumption is local energy source utilization. The article presents a simplified feasibility study of hybrid energy system under Polish law and economic conditions for a self-government unit, that is legally obliged to apply means of energy efficiency improvement. The aim of this paper is to provide a simple algorithm to find optimal hybrid PV and wind power source sizing for a prosumer. Resource data used in analyses are imported from Photovoltaic Geographical Information System and cover a period of one year. The paper includes two different methodologies applied to solve the problem of optimal hybrid energy system sizing. The first approach is heuristic and based on monthly energy balancing while the second is iterative and takes into account hourly energy balance. The results from both methods are compared and verified by HomerPro software, that shows significant differences between two algorithms. At the end economic assessment based on Net Present Value method is performed.