This paper presents a series of economic efficiency studies comparing three different investment variants: without energy storage, with energy stored in batteries and hydrogen installation with a PEM fuel cell stack for a location in Poland. To reach a target, the current solar potential in Poland, the photovoltaic (PV) productivity, the capacity of the energy storage in batteries as well as the size of the hydrogen production system were calculated. The solar potential was determined using archival meteorological data and the Krieg estimation method. A laboratory scale PV system (1 kW) was used to estimate the decrease in real solar installation power during the last 10 years of operation. All analyses were made for a 100 kW photovoltaic array located in Poland using static and dynamic methods of investment project assessment, such as Simply Bay Back Period (SPBP) or Net Present Value (NPV). The results showed that the SPBP amounted to 8.8 years and NPV 54,896 € for non-storage systems. Whereas, for systems with energy stored the economic indexes were, as follow: SPBP = never, NPV = 183,428 € for batteries and SPBP = 14.74 years, NPV = 22,639 € for hydrogen/fuel cell installation. Storage in hydrogen is more advantageous than batteries due to the smaller investment outlays.

The paper presents the results of a study on chemical composition of ashes from three types of waste biomass in terms of fertilizer usefulness. Waste from the process of corn grain drying, including corn cobs, corn grains and corn husk and their mixtures in the ratio 4:1 (v/v) were examined. The study proved that corn grain was the material with the highest concentration of macroelements among those studied (P—21,452 ppm, K—25,970 ppm, S—5911 ppm) and the mixture of corn cobs with corn grains (Ca—81,521 ppm). When microelements were considered, the highest concentration was recorded for corn cobs (Cu—207 ppm, Mn—844 ppm, Zn—857 ppm) and corn husk (Fe—15,100 ppm). The analysis of toxic elements in the ashes of the biomass studied showed their highest concentration in corn husk ash (Ni—494 ppm, Cr—301 ppm, Pb—42.7 ppm, As—4.62 ppm). The analysis showed that regardless of the type of biomass studied, all ashes were strongly enriched (in relation to the average soil content) with phosphorus and corn husk ash with calcium in particular. A slight enrichment in copper and lead was recorded for all ashes, and moderate or low for the other elements. It was found that the examined ashes from biomass, which is a residue from the drying of maize grain, have a high fertilizer usefulness.

The calculation method commonly used in the industry takes into consideration mainly fuel consumption (excluding electricity) and the amount of removed moisture which is reflected in the unit MJ·(Mg·%)⁻¹. This is not a scientific approach because the result will change if the basic moisture is different (drying from 21% to 18% will consume less energy than drying from 18% to 15%). This paper aims to compare the energy consumption of two industrial continuous flow grain dryers powered by LPG and hard coal based on a comprehensive approach to energy efficiency calculation enriched with electricity consumption, flow measurements, and control of grain moisture. It could be useful for manufacturers who could use this method to generate more reliable data in their product datasheets, and it could also be legally regulated as an appropriate tool for calculating the energy consumption of agricultural grain dryers. According to the approach presented in this paper, the S428.CS construction powered by LPG gas had an energy consumption that was 6.14% lower than the DT2532 dryer construction, which used hard coal.

This paper presents the results of a multifaceted analysis of the application of catalytic additives to hemp pellets’ combustion in a low-power boiler. The research concerns the effects of five catalytic additives applied inside the boiler’s combustion chamber—based on TiO₂, MnO₂, Cu(NO₃)₂ × 3H₂O, H₂PtCl₆ solution, and 99.5% pure urea solution—on the quality of hemp pellets’ combustion process. For this purpose, technical and elemental analyses of the used fuel were performed. The chemical composition of exhaust gases (NO_x, CO, SO₂, and PM content) was also examined using an exhaust gas analyzer and a dust meter. The highest reductions in emissions of individual pollutants were for CO (−113%; combustion with Ad3), NO_x (−66%; combustion with Ad 4), SO₂ (−48%; combustion with Ad3), and PM (−78%; combustion with Ad1). The study also determined the amount of avoided costs due to the use of catalytic additives, as well as the annual prevented CO₂ emissions to the atmosphere. Due to rising fuel and energy prices, this study could be helpful for biomass boiler owners who would like to burn locally available raw materials and increase the combustion process’ efficiency.

Carbon monoxide (CO) is an air pollutant commonly formed during natural and anthropogenic processes involving incomplete combustion. Much less is known about biological CO production during the decomposition of the organic fraction (OF), especially originating from municipal solid waste (MSW), e.g., during the aerobic biostabilization (AB) process. In this dataset, we summarized the temperature and the content of process gases (including rarely reported carbon monoxide, CO) generated inside full-scale AB of an organic fraction of municipal solid waste (OFMSW) reactor. The objective of the study was to present the data of the fluctuation of CO content as well as that of O₂, CO₂, and CH₄ in process gas within the waste pile, during the AB of the OFMSW. The OFMSW was aerobically biostabilized in six reactors, in which the technological regimes of AB were dependent on process duration (42–69 days), waste mass (391.02–702.38 Mg), the intensity of waste aeration (4.4–10.7 m³·Mg⁻¹·h⁻¹), reactor design (membrane-covered reactor or membrane-covered reactor with sidewalls) and thermal conditions in the reactor (20.2–77.0 °C). The variations in the degree of waste aeration (O₂ content), temperature, and fluctuation of CO, CO₂, and CH₄ content during the weekly measurement intervals were summarized. Despite a high O₂ content in all reactors and stable thermal conditions, the presence of CO in process gas was observed, which suggests that ensuring optimum conditions for the process is not sufficient for CO emissions to be mitigated. In the analyzed experiment, CO concentration was highly variable over the duration of the process, ranging from a few to over 1,500 ppm. The highest concentration of CO was observed between the second and fifth weeks of the test. The reactor B2 was the source of the highest CO production and average highest temperature. This study suggests that the highest CO productions occur at the highest temperature, which is why the authors believe that CO production has thermochemical foundations.

This paper reports the results of measurements and calculations of heat production from geothermal waters in a Polish geothermal plant in Bańska in the years 2010–2013. Statistical analysis was used to create a regression model and an artificial neural network model. The models allow us to predict the volume of heat produced, depending on outside air temperature. In addition, the study indicates that geothermal energy is one of the most predictable sources of renewable energy, which is important from the point of view of reliability of exploitation. Production of energy from renewable sources, which include geothermal energy, fits the current trends in the energy policy of the Polish state.