The topic of the article considers the functioning of the renewable energy (RE) sector in Poland. This is really important in the context of the energy transition of the national economy because it influences the creation of modern technologies and increases the competitiveness and innovation of the country. Poland is in a process of energy transition where the RE sector has been developing for two decades. The authors aimed to research the RE sector improvement possibilities in Poland, including the influence of this sector on chosen social and economic aspects. Because of this research’s aim a critical situation assessment of RE in Poland was conducted and a survey of a group of experts in this field was also involved. Legal, physical and mental determinants and their influence on RE sector were looked into. In the legal determinant context a necessity to simplify relevant legislation acts in Poland was found. Undoubtedly there is a need to improve several legal acts, including the Distance Act. In physical determinants it was found that solar, wind and biomass energy have the biggest chances for development. In the case of mental determinants the authors paid attention to the need of educating the public about using and obtaining energy. It is also important to make people aware how the RE sector influences the low emission economy positively. This will improve the creation of new jobs and reduce the emissions of harmful substances to the environment.

Pyrolysis has been applied in the human economy for many years, and it has become a significant alternative to the production of chemical compounds, including biofuels. The article focuses mostly on recent achievements in the technical and processing aspects of pyrolysis. The aim of the review is to present the latest research on the process of waste biomass pyrolysis to fuel production. The paper describes the mechanisms of the pyrolysis process, composition, and properties of the obtained fractions, namely pyrolysis gas, bio-oil, and biochar. Additionally, the technical aspects of the pyrolysis process are mentioned, with particular attention to the construction of the reactors. The process of waste biomass pyrolysis allows for obtaining many chemical compounds (second-generation biofuels). Optimization of the pyrolysis process allows obtaining the desired products that are applied in the chemical industry, energy, and transport. The application of pyrolysis gas, oil, and biochar as valuable chemical compounds are related to the intensifying effects of climate change, biofuel production, and waste management in accordance with the principles of sustainable development. In recent years, there has been large-scale research into the use of renewable energy sources through pyrolysis. This will make it possible to significantly reduce the carbon footprint and produce second-generation biofuels in a sustainable manner. Current research into the mechanisms of pyrolysis processes is promising, and will therefore provide access to clean and low-cost compounds that will have broad applications in the energy, chemical, agricultural, and transportation industries.

Plastics-based materials have a high carbon footprint, and their disposal is a considerable problem for the environment. Biodegradable bioplastics represent an alternative on which most countries have focused their attention to replace of conventional plastics in various sectors, among which food packaging is the most significant one. The evaluation of the optimal end-of-life process for bioplastic waste is of great importance for their sustainable use. In this review, the advantages and limits of different waste management routes—biodegradation, mechanical recycling and thermal degradation processes—are presented for the most common categories of biopolymers on the market, including starch-based bioplastics, PLA and PBAT. The analysis outlines that starch-based bioplastics, unless blended with other biopolymers, exhibit good biodegradation rates and are suitable for disposal by composting, while PLA and PBAT are incompatible with this process and require alternative strategies. The thermal degradation process is very promising for chemical recycling, enabling building blocks and the recovery of valuable chemicals from bioplastic waste, according to the principles of a sustainable and circular economy. Nevertheless, only a few articles have focused on this recycling process, highlighting the need for research to fully exploit the potentiality of this waste management route.

Both the global and European energy sectors have been undergoing a deep transition for several years, associated with a reduction in the overall share of conventional coal-based energy in favor of new technologies, especially energy from renewable sources (RES). This transition is moving from centralized production towards distributed technologies and from providing only energy to end users towards combining innovative products and services with it. Electricity consumers are becoming prosumers connected to the grid and generating an increasing amount of energy. The original goal of decision-makers was to stop global warming and improve air quality. After Russia's aggression of Ukraine in 2022, the EU transition efforts accelerated, and concerns about the climate were joined by issues related to energy security. After the painful experiences of the last several months, Europe wants to become independent from energy raw materials and their unstable suppliers as soon as possible, securing markets against price fluctuations, blackmail and unfair practices of some sellers. The aim of the article is to describe the current situation of energy and heat production from RES in selected countries in the aspect of contemporary energy transition (ET) processes. The achievement of the goal made it possible to present the European RES market in 2022, discuss the actions taken by European countries towards decarbonization and propose recommendations for the further development of the renewable energy market. The ET in Europe has been going on for over a dozen years, although there are countries, such as Norway, that use almost 100 % of renewable energy, as well as those that still largely use conventional fuels, such as Poland. In European countries, the energy mix of renewable energy, energy storage and green hydrogen should be developed. Green hydrogen produced in the electrolysis process from surplus renewable energy is an energy carrier with versatile applications both in the energy sector and in European industry.

Every year the interest in biofuels, including biomethane, grows in Poland. Biomethane, obtained from biogas, is widely used in the Polish economy; the most important two applications are as gas injected into the gas grid and as automotive fuel. The aim of this work is to determine the potential for the development of the biomethane sector in Poland. The following article presents the technological stages of biomethane extraction and purification. The investment process for biogas/biomethane installation is presented in the form of a Gannt chart; this process is extremely long in Poland, with a duration of three years. In the coming months, the Polish Oil Mining and Gas Extraction will begin to invest in biomethane, which will be connected to the gas grid, while the Polish oil refiner and petrol retailer, Orlen, will invest in biomethane to be used as automotive fuel. This article includes a SWOT (Strengths, Weaknesses, Opportunities, Threats) and PEST (Political, Economic, Social, Technological) analysis of the biogas/biomethane sector in Poland. The main barriers to the development of the biogas/biomethane sector in Poland are high investment costs, long lead times and a strong conventional energy lobby. The most important advantages of biogas/biomethane technology in Poland include environmental aspects, high biomethane potential and well-developed agriculture. The development of biogas/biomethane technology in Poland will slowly reduce environmental pollution, reduce carbon dioxide emissions and allow for partial independence from the importing of natural gas.

The history of hydro energy in Poland was shown in the article. The first mills were built in the ninth century and the first hydro energy plant was opened in 1896. In 1935, there were 8000 water energy plants and dozen other installations using water energy. War action and nationalisation have caused the crash of hydro energy in Poland. At the moment, there are 761 water energy plants amounting to 994 MW. The Lower Vistula Cascade was described but also use of water for energy purposes in heat plants and waste treatment plants. Technical potential of hydro energy is major. Using already exciting heaps (there are 16,005), it is possible to obtain 14.27 PJ. SWOT analysis has shown that hydro energy in Poland is a well-mastered technology and allows small water retention. Investing in hydro energy in Poland requires a lot of documents. In addition, energetic law is constantly changing. Influence of hydro energy on environment was presented. It was concluded that small hydro energy development is definitely advised in Poland. Small hydro energy stations allow to produce energy and allow small retention in steppe Poland.