To reduce the contribution of coal mine methane to air pollution and the greenhouse effect, environmentally friendly catalytic technology has been proposed. Tri-reforming over Ni catalyst was used to utilize coal mine methane of various compositions into valuable products. The temperature and time-on-stream dependences of the conversion of feedstock and products yield were determined for the ventilation air methane (VAM, methane concentration CCH4 ≤ 1 vol. %); coal mine/degassing methane of operating (CMM, CCH4 = 25–60 vol. %) or abandoned (AMM, CCH4 = 60–80 vol. %) coal mines; methane from unrelieved coal beds – virgin coal seams (CBM, CCH4 ≥ 80 vol. %) in the temperature range from 150 to 850 °C, atmospheric pressure and volumetric flow rate of 24,000 h−1. The results of catalytic tests were compared with the thermodynamic analysis data and optimization of process conditions was performed. It was found that methane conversion increases with growing O/C molar ratio (0.18 → 41.8) in the initial mixture and at 700 °C it was 26, 42, 84 and 92% for the AMM (70 vol. % CH4 + 30 vol. % air), CMM-2 (50.0 vol. % CH4 + 50 vol. % air), CMM-1 (30.0 vol. % CH4 + 70 vol. % air) and VAM (1.0% CH4 + 99 vol. % air), respectively. The hydrogen concentration in the reaction products reached 30–40 vol. %. The addition of oxidizing agents (CO2 + H2O) to high-methane-containing coal gas leads to a significant increase in methane conversion (39 → 91%), hydrogen yield (48 → 81%) and their stability with time on stream due to optimization of an O/C molar ratio (0.42 → 1.3). Utilization of coal mine methane using the proposed catalytic technology solves a number of important problems related to the conservation of natural resources, environmental protection and the safety of coal mining, all of which are essential for advancing clean coal technologies as a key factor of green mining and sustainable development.
Biomass torrefaction is a thermochemical process that transforms biomass into a more energy-dense fuel, producing solid biochar, volatile organic compounds, and gases such as carbon dioxide (CO₂), carbon monoxide (CO), and nitrogen oxides (NOx). In this study, the effects of solar drying, as a sustainable preprocessing method, and subsequent torrefaction were evaluated under varying initial moisture content levels of 5%, 10%, 15%, and 20%. The drying conditions of wood chips and the torrefaction process were documented for a sustainable biomass drying system using solar energy. Comprehensive proximate and final analysis and flue gas monitoring analyzed the torrefied biomass’s emission characteristics and combustion efficiency. Results showed that higher initial moisture content increased hydrogen and volatile matter, decreased fixed carbon, and marginally raised the higher heating value. This study shows that solar drying optimizes biomass pretreatment and is a cost-effective and environmentally friendly alternative to conventional drying. This work sheds light on the relationship between initial moisture content, emission characteristics, and combustion behavior, aiding bioenergy development.
In 2018, the European Clean Energy Package introduced the concept of Renewable Energy Communities (RECs) to promote the use of renewable energy sources and local energy consumption. This initiative also supports increased self-sufficiency and mitigates the negative impact of renewable energy on grid management. RECs consist of groups of members who share energy, and various combinations of REC members can be assessed using different KPIs. The SIMUL-REC simulation code has been developed for these purposes, incorporating an innovative parametrization for self-consumption and self-sufficiency within RECs. This approach enables an analysis of the KPIs’ dependence on the production/consumption ratio, as well as the influence of seasonal and daily effects, thereby guiding the identification of the most suitable configurations. A complex case study in Lignano Sabbiadoro (Italy) is analyzed, involving 88 participants and nearly 50 detailed load profiles. The results, in addition to electricity consumption and production, primarily focus on the self-sufficiency rate (40%), the significant contribution of shared energy (57%) compared to direct self-consumption (19%), and their parametrization. New Italian tariff premiums introduced in 2024 create new scenarios, and initial economic evaluations have been conducted using two contrasting cases.
Integrating renewable energy systems into urban neighborhoods is essential for achieving sustainable development and decarbonization. This study investigates the integration of building-integrated photovoltaics and energy-sharing mechanisms to achieve net-zero energy communities in low-income urban neighborhoods. Using a social housing neighborhood in Ioannina, Greece, within Local Climate Zone 6, as a case study, we evaluated energy performance through hourly simulations. Annual PV generation (1096.2 MWh) exceeded the total load (931.5 MWh), achieving net-positive energy status. Incorporating a 1000 kWh battery energy storage system improved the hourly load match from 39.1 to 81% and reduced grid imports and exports by 52% and 37%, respectively. The findings underscore the potential of energy-sharing systems to enhance urban energy resilience and self-sufficiency. In addition, the study emphasizes the importance of leveraging Local Climate Zone characteristics to design energy systems tailored to urban contexts. Policy incentives and further research are recommended to promote cost-effective energy-sharing models in similar contexts.