The production of biogas from biodegradable waste generated in all sectors of the economy in Poland is a key issue for the diversification of energy sources and climate neutrality. The biogas balances presented in the literature based on bio-waste often contain overly optimistic data, which in reality only represent the theoretical potential of biogas in Poland. The pragmatic approach presented in this study fills a gap in research by presenting a technical balance of biogas (real potential) that can be realistically achieved. The objective of the work was to perform a biogas balance in the context of electricity and heat generation in cogeneration units. The tests made it possible to estimate the technical potential of biogas, depending on the source of its generation, the possibility of its conversion to biomethane and biohydrogen and the methods of its use. The research results showed a 30% increase in biogas potential on an annual basis compared to the current state, resulting in a 29% increase in electricity production and a 28% increase in heat production. The technical potential of biogas was estimated at 2186.62 million m³, which would allow for the production of 4627.06 GWh of electricity and 1869.64 TG of heat. The technical balance of biogas and the potential energy production can serve as input material for developing plans and strategies for the development of renewable energy sources in Poland. The work is consistent with the issues of balancing the renewable energy resources from biogas and the methods of conversion into other energy carriers using sustainable energy transformations in order to optimise energy production processes.

This paper presents the energy potential of biogas obtained from the anaerobic digestion (AD) of sewage sludge (SS) preceded by thermal hydrolysis (THP) using Cambi THP^® technology. The presented data are for the Tarnów (Poland) wastewater treatment plant for the year 2020. A detailed energy balance of biogas and its use in the cogeneration process and in the production of heat in the water boiler and the steam boiler is presented. The article contains data on the amount of processed SS and the content of dry matter and dry organic matter at different stages of the technological process. The annual plant operation resulted in the production of 3,276,497 Nm³ of biogas as a result of processing 8684 tonnes of dry solids (tDS) of municipal SS from the Tarnów wastewater treatment plant (WWTP) and regional WWTPs. The energy potential of the produced biogas was 75,347.06 GJ. The average calorific value of biogas was 23,021 kJ/Nm^3.. The obtained biogas production allowed us to cover the thermal energy demand of the THP 100%. The annual average specific biogas conversion rate during the study period was 0.761 Nm³/kg of dry organic matter reduced and the average organic matter content reduction in the sludge was 64.60%.

The issue of enhancing energy recovery efficiency is a key concern within the European Union’s climate protection efforts. In particular, it applies to all processes and plants for the harvesting, gathering, and conversion of energy. The abandonment of fossil fuels in favour of alternative energy sources, and the increasing of energy efficiency and its recovery, is now a widely accepted direction of energy development. This study focuses on facilities that recover and process energy from municipal waste left after recycling processes, known as waste-to-energy (WtE) plants. These plants’ energy recovery efficiency is governed by the R1 Formula in EU countries. This report is based on an analysis of four years of operational data from selected Polish municipal waste incinerators, supplemented by a discussion of various studies on energy recovery efficiency. The primary objective of this report is to evaluate the effectiveness of these plants in contributing to sustainable waste management and energy recovery. The main effect of the developed report is the set of results of the energy recovery efficiency factor values, determined based on the R1 formula valid in the EU legislation, tabulated and graphically illustrated, and calculated for five selected Polish waste-to-energy plants. The presented results, with their graphical interpretation, discussion, and conclusions, provide insights into several factors influencing the value of the R1 efficiency factor. They can be a valuable contribution to operators of waste-to-energy plants, especially those operating in countries outside the EU.

In this work, the novel design of a sliding mode TriboElectric Nano Generator (TENG)—which can utilize vibration amplitude of a few hundred microns to generate useful electric power—is proposed for the first time. Innovative design features include motion modification to amplify relative displacement of the TENG electrodes and use of biological material-based micron-sized powder at one of the electrodes to increase power output. The sliding mode TENG is designed and fabricated with use of polyurethane foam charged with the biological material micropowder and PolyTetraFluoroEthylene (PTFE) strips as the electrodes. Experimentations on the prototype within frequency range of 0.5–6 Hz ensured peak power density of 0.262 mW/m², corresponding to the TENG electrode size. Further numerical simulation is performed with the theoretical model to investigate the influence of various design parameters on the electric power generated by the TENG. Lastly, application of the proposed TENG is demonstrated in a wearable device as an in-shoe sensor. Conceptual arrangement of the proposed in-shoe sensor is presented, and numerical simulations are performed to demonstrate that the real size application can deliver peak power density of 0.747 mW/m² and TENG; the voltage will accurately represent foot vertical force for various foot force patterns.

The priority task of the milk processing industry is in reducing the specific energy consumption of milk fat dispersion while simultaneously ensuring a high dispersion of milk emulsion. One of the possible ways to solve this problem is by developing and implementing a little-studied jet milk homogenizer of the slot type. In it, homogenization occurs by implementing the method of the separate feeding of cream, which allows creating the maximum difference between the speeds of skim milk and cream, which is a necessary condition for effective dispersion. Analytical dependences have been found that relate power and specific energy consumption to the performance of a milk homogenizer with the separate cream supply, the diameter of the annular gap, the fat content of normalized milk and cream, and the cream supply speed. The rational value of the fat content of the cream used for homogenization is analytically substantiated; in order to reduce the specific energy consumption of the process, their fat content should be higher than 20%. The most significant increase in the energy costs of dispersion is observed when processing milk with a fat content of less than 3–4%, while the use of cream with a fat content of less than 20% leads to a multiple increase in the energy costs of the process. The research results indicate the hyperbolic nature of the dependence of the homogenizer power on its productivity. Supplying the cream through an annular gap of small diameter allows reducing the main component of dispersion energy costs by eight times. The obtained data indicate the existence of a deviation within 5–10% of the experimental power values from the analytical ones, which is explained by the influence of the efficiency of pumps, drives, and losses in the connecting fittings.

This study reports the use of front-face fluorescence spectroscopy with principal component analysis (PCA) as a tool for the characterisation of selected Polish herbhoneys (raspberry, lemon balm, rose, mint, black current, instant coffee, pine, hawthorn, and nettle). Fluorimetric spectra registered in the ranges ascribed to fluorescence of amino acids, polyphenols, vitamins, and products of Maillard’s reaction enabled the comparison of herbhoney compositions. Obtained synchronous spectra combined with PCA were used to investigate potential differences between analysed samples and interactions between compounds present in them. The most substantial influence on the total variance had the intensities of polyphenols fluorescence. These intensities were the main factor differentiated by the analysed products.