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Hydrogen (H2) production from biomass has emerged as a promising alternative to fossil-based pathways, addressing the global demand for low-carbon energy solutions. This study compares the environmental impacts of two biomass-based H2 production processes, biogas reforming and agricultural residue gasification, through a life cycle assessment (LCA). Using real-world data from the literature, the analysis considered key system boundaries for each process, including biogas production, reforming, and infrastructure, for the former, and biomass cultivation, syngas generation, and offgas management, for the latter. Environmental impacts were evaluated using SimaPro software (Version 9.4) and the ReCiPe midpoint (H) method. The results revealed that biogas reforming emits approximately 5.047 kg CO2-eq per kg of H2, which is 4.89 times higher than the emissions from agricultural residue gasification (1.30 kg CO2-eq/kg H2), demonstrating the latter’s superior environmental performance. Gasification consumes fewer fossil resources (3.20 vs. 10.42 kg oil-eq) and poses significantly lower risks to human health (1.51 vs. 23.28 kg 1,4-DCB-eq). Gasification water consumption is markedly higher (5.37 compared to biogas reforming (0.041 m3/kg H2)), which is an important factor to consider for sustainability. These findings highlight gasification as a more sustainable H2 production method and emphasize its potential as an eco-friendly solution. To advance sustainability in energy systems, integrating socio-economic studies with LCA is recommended, alongside prioritizing agricultural residue gasification for hydrogen production.

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Environmental restoration and sustainable energy solutions require effective management and utilization of agricultural crop residues to reduce greenhouse gas emissions. Biowastes are a valuable resource that can be converted into biofuels and their byproducts, solving the energy crisis and reducing environmental impact. In this study, teff husk, primarily generated in Ethiopia during the production of teff within the agro-industrial sector, is used as a feedstock for slow pyrolysis. Ethiopia generates an estimated annual production of over 1.75 million tons of teff husk, a significant portion of which is incinerated, resulting in significant pollution of the environment. This study focuses on assessing teff husk as a potential material for slow pyrolysis, a crucial stage in biochar production, to tap into its biochar-producing potential. To identify the composition of biomass, the teff husk underwent an initial analysis using thermogravimetry. The significant presence of fixed carbon indicates that teff husk is a viable candidate for pyrolytic conversion into biochar particles. The process of slow pyrolysis took place at three temperatures—specifically, 400, 450, and 500 °C. The maximum biochar yield was achieved by optimizing slow pyrolysis parameters including reaction time, temperature, and heating rate. The optimized reaction time, temperature, and heating rate of 120 min, 400 °C, and 4.2 °C/min, respectively, resulted in the highest biochar yield of 43.4 wt.%. Furthermore, biochar’s physicochemical, SEM-EDX, FTIR, and TGA characterization were performed. As the temperature of biochar increases, its carbon content and thermal stability increases as well. Unlike fuel recovery, the results suggest that teff-husk can be used as a feedstock for biochar production.

Due to the depletion of fossil fuels and the destruction wrought by global warming caused by the combustion of fossil fuels, the search for renewable energy sources has become a major global concern. This study aimed to assess the bio-oil production from teff husk via slow pyrolysis process. The pyrolysis of teff husk took place in a batch reactor at a temperature between 400 °C and 500 °C with a 120 min retention time. At 450 °C, the pyrolysis process produced 32.96 wt.% of optimum bio-oil yield and had a HHV of 25.32 MJ/kg. TGA, FTIR, and SEM-EDX were used to analyze the produced bio-oil to investigate its thermal decomposition, functional groups, and surface morphology with its elemental composition, respectively. Alcohols, aromatic, phenols, alkanes, esters, and ethers were the primary compounds of the bio-oil produced by the slow pyrolysis of teff husk. The HHV of the biochar ranged from 21.22 to 22.85 MJ/kg. As a result, teff husk can be used to make biofuel; however, further bio-oil upgrading is needed for the produced teff husk bio-oil to be used effectively and commercially. Overall, the slow pyrolysis of teff husk offers a chance to produce biofuels with enhanced value that can be used for additional purposes.

Poland is facing demanding challenges to achieve a sustainable energy mix in the near future. Crucial and tough decisions must be made about the direction of the national energy economy, safety, and environmental impact. Considering the electricity and heating demand forecast, this paper proposes an optimization model based on the Grey Wolf Optimizer meta-heuristic to support the definition of ideal energy mix considering the investment and operational costs. The proposed methodology uses the present energy mix in Poland (the most recent values are from 2017) to calibrate the model implemented in the EnergyPLAN tool. Afterwards, EnergyPLAN relates to an optimization process allowing the identification of the most convenient energy mix in 2040 in Poland. The values obtained are compared with those proposed by Polish public entities showing advantage regarding the global costs of the project nevertheless respecting the same levels of CO2 and the energy import and export balance. The expected savings can achieve 1.3 billion euros a year and more than 8 million tonnes of CO2 emission reduction. Sensitivity analysis considering the decrease of the global cost of renewables-based sources is also presented.

The increase in frequency and intensity of natural disasters is related to the changing global average temperature. Reducing greenhouse gas emissions and the extraction of natural resources is one of the solutions proposed by the European Green Deal and the 17 Sustainable Development Goals (SDGs) approved by the United Nations. The article presents research on municipal solid waste incineration bottom ash (MSWIBA), which is the basis for its circulation in the idea of the circular economy. The MSWIBA study presents differential thermogravimetry (DTG), glassy phase, and mortars using CSA and CEM I. The management of MSWIBA contributes to reducing greenhouse gas emissions and the extraction of natural resources.

The amount of waste generated by society is constantly increasing. Consequently, there is a need to develop new and better methods of treating it. A significant part of municipal waste is biowaste, which can be treated as a source of valuable resources such as nutrients, organic matter, and energy. The present work aims to determine the properties of the tested household biowaste and the possibility of using it as feedstock in slow pyrolysis to obtain biochar. The slow pyrolysis process of the biowaste was carried out in an electrically heated Horizontal Tube Furnace (HTF) at temperatures of 400 °C, 500 °C, and 600 °C in a nitrogen atmosphere. The analysis showed that depending on the type and composition of the biowaste, its properties are different. All the biowaste tested has a high moisture content (between 63.51% and 81.53%), which means that the biowaste needs to be dried before the slow pyrolysis process. The characteristics of kitchen biowaste are similar to those of food waste studied by other researchers in different regions of the world. In addition, the properties of kitchen biowaste are similar to those of the typical biomasses used to produce biochar via slow pyrolysis, such as wood, almond shells, and rice husks. Both kinds of garden biowaste tested may have been contaminated (soil, rocks) during collection, which affected the high ash content of spring (17.75%) and autumn (43.83%) biowaste. This, in turn, affected all the properties of the garden biowaste, which differed significantly from both the literature data of other garden wastes and from the properties of typical biomass feedstocks used to produce biochar in slow pyrolysis. For all biowaste tested, it was shown that as the pyrolysis temperature increases, the yield of biochar decreases. The maximum mass yield of biochar for kitchen, spring garden, and autumn garden biowaste was 36.64%, 66.53%, and 66.99%, respectively. Comparing the characteristics of biowaste before slow pyrolysis, biochar obtained from kitchen biowaste had a high carbon content, fixed carbon, and a higher HHV. In contrast, biochar obtained from garden biowaste had a lower carbon content and a lower HHV.

In order to use secondary waste from an incineration plant, it is necessary to process or treat it. Valorization of municipal solid waste incineration bottom ash (MSWIBA) is a popular treatment method. Moreover, there are other possibilities, such as alkaline pre-treatment, which can be used for the rest of the secondary waste from incineration plants, especially hazardous fly ash. The purpose of this study is to show the problem of secondary waste in Poland in relation to the rest of Europe. Due to the physicochemical research of secondary waste, the possibilities of the procedure and its management are indicated. By analyzing the literature and the market, the latest possibilities for improving the physicochemical properties of secondary waste are proposed. Searching for new methods for waste management is essential to the environment. This manuscript presents the problem of the increasing amount of waste, as well as possibilities to close the loop, and minimize the negative impact on the environment. Additionally, the article shows that environmental benefits can be achieved by replacing raw material with secondary waste.

The use of waste for energy purposes could become widespread and the radical lowering of the costs associated with that process could occur, if the resulting fuel did not have the status of waste. The key issue in removing the status of waste for a given substance is to eliminate the environmental impact of its use. Currently, there are no known fuels whose combustion does not lead to a negative impact on the environment, even to a minimum extent. It is therefore necessary to set a threshold of environmental impact at which we “recognize” a fuel to be harmless to the environment. The ecological impact of lignite was assumed in this text to be such a threshold. This paper proposes a methodology for determining the limit of environmental impact of fuel from waste. It also presents the results of our own research on the morphological and elemental composition of a waste mixture created by the separation of the over-screen fraction of municipal waste undesirable for a fuel, namely, chlorine carriers (PVC), multi-material waste, ferrous and non-ferrous metals, and non-combustible fractions (ash). The results obtained were used to assess the relative environmental impact of a waste mixture used as fuel.

Sustainable Development Goals (SDGs) constitute an action plan for the environment and people. One of the main goals is to limit the increase in global average temperature to 2 °C and aim for a stop at 1.5 °C. The goals of the circular economy (CE) are in line with the SDGs. In the waste management chain, the last CE element is a recovery in the municipal solid waste incineration plant (MSWIP). However, during recovery, municipal solid waste bottom ash (MSWIBA) is created (in about 30% of the bunch). The development of MSWIBA in the construction industry is a possibility of closing the cycle. This article shows the MSWIBA formation process, alkali pre-treatment of MSWIBA, and its geopolymerisation. Studies have determined the mechanical properties of geopolymer with MSWIBA and leachability from crushed and from monolith geopolymer. Alkali pre-treatment improves MSWIBA mechanical properties and upgrades immobilisation. Moreover, geopolymerisation is a better solution than concreting, because of the lack or low consumption of high-emission and energy-intensive cement. A SWOT analysis was carried out for the proposed solution.