TY - JOUR A1 - Chaturvedi, Pushpendra Kr. A1 - Kumar, Nand A1 - Toftum, Jørn A1 - Andersen, Rune Korsholm A1 - Lamba, Ravita A1 - Mehta, Kedar T1 - Exploring influential parameters affecting residential building energy use: advancing energy efficiency through machine learning JF - Clean Technologies and Environmental Policy UR - https://doi.org/10.1007/s10098-025-03301-x Y1 - 2025 UR - https://doi.org/10.1007/s10098-025-03301-x SN - 1618-9558 VL - 27 IS - 11 SP - 6975 EP - 6996 PB - Springer CY - Berlin ER - TY - CHAP A1 - Reum, Tobias A1 - Natale, Christian A1 - Schmitt, David A1 - Dongellini, Matteo A1 - Naldi, Claudia A1 - Summ, Thorsten A1 - Morini, Gian Luca A1 - Schrag, Tobias ED - Zilio, Claudio ED - Busato, Filippo ED - Mazzarella, Livio ED - Noro, Marco T1 - Control Strategies for Active Regeneration in a Dual-Source Heat Pump T2 - Proceedings of the 15th REHVA HVAC World Congress - CLIMA 2025: Volume 1 UR - https://doi.org/10.1007/978-3-032-06806-4_55 Y1 - 2025 UR - https://doi.org/10.1007/978-3-032-06806-4_55 SN - 978-3-032-06806-4 SP - 564 EP - 574 PB - Springer CY - Cham ER - TY - CHAP A1 - Schmitt, David A1 - Reum, Tobias A1 - Summ, Thorsten A1 - Schrag, Tobias ED - Zilio, Claudio ED - Busato, Filippo ED - Mazzarella, Livio ED - Noro, Marco T1 - Comparison of Heat Pump Modelling Approaches for Predictive Controllers to Optimize the Efficiency of Modulating Air-Source Heat Pumps: A Case Study from South Germany T2 - Proceedings of the 15th REHVA HVAC World Congress - CLIMA 2025: Volume 1 UR - https://doi.org/10.1007/978-3-032-06806-4_59 Y1 - 2025 UR - https://doi.org/10.1007/978-3-032-06806-4_59 SN - 978-3-032-06806-4 SP - 611 EP - 620 PB - Springer CY - Cham ER - TY - JOUR A1 - Rouegui, Meryem A1 - Bellabair, Hind A1 - El Asli, Abdelghani A1 - Amar, Amine A1 - Zörner, Wilfried A1 - Rachidi, Fouad A1 - Lghoul, Rachid T1 - Bio-Methanization of Sheep Manure and Beet Waste in the Meknes–Fès Region, Morocco: Effects of Pretreatment and Machine Learning Applications for Biochemical Methane Potential Prediction JF - Recycling N2 - Sheep manure and beet waste (the uneatable leaf part of the beet) are promising feedstock for biogas production due to their abundance and organic richness. However, their high lignocellulosic content reduces anaerobic digestibility and controls methane yield. This study investigates the effect of various pretreatment strategies, namely physical, thermal, and combined physical–thermal methods, on the Biochemical Methane Potential (BMP) of sheep manure and beet waste. Batch anaerobic digestion experiments were conducted under mesophilic conditions, with BMP values recorded for each treatment. The highest BMP for sheep manure, 125 Nml CH4/g VS, was achieved using combined physical and thermal pretreatment. This approach enhanced methane production by 16%, 25%, and 60% compared to physical pretreatment (PP) alone, thermal pretreatment (TP) alone, and no pretreatment, respectively, while the one BMP for beet waste is 80 Nml CH4/g VS and obtained with thermal pretreatment. To predict BMP outcomes, three machine learning approaches are applied, namely Linear Regression (LM), Random Forest Regression (RFR), and Gradient Boosting Machine (GBM), using digestion time (N days), total solids (Ts), volatile solids (Vs), pretreatment type, and biomass type. The variance analysis confirmed that the interaction between pretreatment and biomass type significantly improved model performance. While diagnostic checks revealed non-linear patterns limiting the linear model, ensemble methods achieved stronger results. The RFR model explained 79.5% of the variance with a Root Mean Square Error (RMSE) of about 15.7, whereas the GBM model achieved the lowest RMSE of 5.05. GBM captures complex non-linear interactions. In addition, variable importance analyses identified digestion time, solid content, and pretreatment as the most influential factors for methane yield, with the combined chemical and physical pretreatment producing the highest biogas outputs. These findings underscore the potential of advanced machine learning models, particularly GBM (Gradient Boosting Machine), for optimizing anaerobic digestion strategies and maximizing biogas recovery from sheep manure and beet waste. UR - https://doi.org/10.3390/recycling10060213 Y1 - 2025 UR - https://doi.org/10.3390/recycling10060213 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-64862 SN - 2313-4321 VL - 10 IS - 6 PB - MDPI CY - Basel ER - TY - JOUR A1 - Mehta, Kedar A1 - Jain, Rushabh Bansilal A1 - Zörner, Wilfried T1 - Agrivoltaics Around the World: Potential, Technology, Crops and Policies to Address the Energy–Agriculture Nexus for Sustainable and Climate-Resilient Land Use JF - Energies N2 - The urgent pursuit of climate-resilient agriculture and clean energy systems, central to the Energy–Agriculture Nexus and the UN Sustainable Development Goals, has accelerated global interest in agrivoltaic (Agri-PV) technologies. This paper presents a global systematic review and meta-analysis of 160 peer-reviewed studies, structured through a five-stage thematic synthesis: (1) mapping global and regional Agri-PV deployment and potential, (2) analyzing system design and modeling methodologies, (3) evaluating crop suitability under partial shading, (4) reviewing enabling policies and regulatory frameworks, and (5) assessing techno-economic feasibility and investment barriers. Results reveal that Europe and Asia lead Agri-PV development, driven by incentive-based policies and national tenders, while limited regulatory clarity and high capital costs constrain wider adoption. Despite technological progress, no integrated model fully captures the coupled energy, water, and crop dynamics essential for holistic assessment. Strengthening economic valuation, policy coherence, and standardized modeling approaches will be critical to scale Agri-PV systems as a cornerstone of sustainable and climate-resilient land use. UR - https://doi.org/10.3390/en18246417 Y1 - 2025 UR - https://doi.org/10.3390/en18246417 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-65288 SN - 1996-1073 VL - 18 IS - 24 PB - MDPI CY - Basel ER - TY - JOUR A1 - Mehta, Kedar A1 - Lwakatare, Bertha A1 - Zörner, Wilfried A1 - Ehrenwirth, Mathias T1 - Mini-grid performance in Sub-Saharan Africa: case studies from Tsumkwe and Gam, Namibia JF - Sustainable Energy Research N2 - This paper investigates the performance analysis and operational challenges of mini-grids in Sub-Saharan Africa, focusing on the Tsumkwe and Gam mini-grids, the only officially recognized mini-grids in Namibia. The study addresses a critical gap in understanding mini-grid efficiency, technical difficulties, and future potential. The key research questions focus on assessing mini-grid performance, identifying technical and operational challenges, quantifying the relationship between electricity demand and supply, and providing recommendations for enhancing rural electrification through mini-grids. These insights are crucial for evaluating the effectiveness of mini-grids in the African context and understanding their role in advancing rural electrification. By using a mixed-method approach, the research combines quantitative and qualitative data to offer a comprehensive analysis of these two mini-grid systems of Namibia. The data collected from 2017 to 2022 include metrics on energy supply, consumption, photovoltaic generation, community load, and meteorological conditions. Qualitative insights were gathered through field visits, surveys, and interviews with mini-grid operators, allowing for a thorough examination of community perspectives, operational issues, and technical performance. The findings reveal that the Tsumkwe mini-grid has seen a decline in efficiency due to maintenance problems and battery overheating, while the Gam mini-grid, initially oversized, now struggles with increased demand and new connections. This study provides the first detailed technical insights, identifies consumer archetypes, and evaluates the energy dynamics of mini-grids in Namibia. Recommendations include improved maintenance protocols, advanced battery management, and enhanced data monitoring. By analyzing Tsumkwe and Gam, this paper offers valuable lessons for mini-grid development in Sub-Saharan Africa, stressing the need for continuous evaluation and strategic improvements to achieve sustainable rural electrification. UR - https://doi.org/10.1186/s40807-025-00174-y Y1 - 2025 UR - https://doi.org/10.1186/s40807-025-00174-y UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-65316 SN - 2731-9237 VL - 12 IS - 1 PB - SpringerOpen CY - Singapore ER - TY - JOUR A1 - Chaturvedi, Pushpendra Kr. A1 - Kumar, Nand A1 - Lamba, Ravita A1 - Mehta, Kedar T1 - Multi-objective optimization of glazing and shading configurations for visual, thermal, and energy performance of cooling dominant climatic regions of India JF - Clean Technologies and Environmental Policy UR - https://doi.org/10.1007/s10098-024-03114-4 Y1 - 2024 UR - https://doi.org/10.1007/s10098-024-03114-4 SN - 1618-9558 VL - 27 IS - 9 SP - 4909 EP - 4932 PB - Springer CY - Berlin ER - TY - JOUR A1 - Mehta, Kedar A1 - Betz, Florian T1 - Agri-photovoltaics in India: Geospatial suitability for sustainable water–energy–food nexus solutions JF - Energy for Sustainable Development UR - https://doi.org/10.1016/j.esd.2025.101915 Y1 - 2025 UR - https://doi.org/10.1016/j.esd.2025.101915 SN - 2352-4669 VL - 2026 IS - 91 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Mehta, Kedar A1 - Ehrenwirth, Mathias A1 - Zörner, Wilfried A1 - Greenough, Richard T1 - Need of energy transition at roof of the world BT - Correlative approach to interpret energy identity of high-altitude Central Asian communities JF - Energy for Sustainable Development UR - https://doi.org/10.1016/j.esd.2023.101271 Y1 - 2023 UR - https://doi.org/10.1016/j.esd.2023.101271 SN - 2352-4669 SN - 0973-0826 VL - 2023 IS - 76 PB - Elsevier CY - Amsterdam ER - TY - CHAP A1 - Idda, Johannes A1 - Selleneit, Volker A1 - Holzhammer, Uwe T1 - Hochflexible Biomethan-BHKW-Anlagen und der Einfluss eines Biomethanspeichers auf den möglichen Biogaspreis für Post-EEG-Biogasanlagen T2 - Biogas in der Landwirtschaft – Stand und Perspektiven: FNR/KTBL-Kongress am 8. und 9. September 2025 Y1 - 2025 SP - 94 EP - 101 PB - KTBL CY - Darmstadt ER - TY - JOUR A1 - Mehta, Kedar A1 - Lamba, Ravita A1 - Sinha, Sunanda A1 - Kumar, Nand T1 - BIPV in India: Opportunities, challenges, and pathways for urban planning and smart cities JF - Solar Compass N2 - As India urbanizes rapidly, sustainable energy solutions have become a priority to meet rising energy demands and mitigate environmental impacts. Building-Integrated Photovoltaics (BIPV) offer a promising approach to harness solar energy within urban infrastructure, transforming buildings into renewable energy assets. Unlike conventional rooftop PV systems, BIPV maximizes urban space utilization while enhancing architectural aesthetics and energy efficiency. However, the adoption of BIPV in India remains limited due to factors such as regulatory barriers, lack of standardized designs, and high initial costs. This study uses SWOT (Strengths, Weaknesses, Opportunities, Threats) and TOWS (Threats, Opportunities, Weaknesses, Strengths) analyses to assess the potential, opportunities, and challenges of BIPV in India’s urban planning. It then discusses policy implications and offers practical recommendations for implementation in Indian cities. Key findings of this study indicate that BIPV adoption in India can significantly contribute to urban sustainability by reducing carbon emissions, improving energy self-sufficiency, and lowering long-term operational costs. The SWOT and TOWS analysis reveal that while BIPV presents opportunities for smart urban integration, challenges such as high initial investments and lack of awareness must be addressed through targeted policies and incentives. Additionally, global case studies highlight successful BIPV implementations, providing valuable lessons for India’s urban planning strategies. UR - https://doi.org/10.1016/j.solcom.2025.100133 Y1 - 2025 UR - https://doi.org/10.1016/j.solcom.2025.100133 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-61824 SN - 2772-9400 VL - 2025 IS - 15 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Bott, Christoph A1 - Dressel, Ingo A1 - Bayer, Peter T1 - Paraffin wax as self-sealing insulation material of seasonal sensible heat storage systems—A laboratory study JF - PLOS ONE N2 - Seasonal heat storage is considered as one of the key elements on the path to a low-emission economy. Embedded in local district heating networks, they raise the share of renewable energies and balance out highly fluctuating supplies of e.g. solar systems or windmills. The technology of seasonal heat storage can be described as almost technically mature, with well-established concepts and some systems being in operation for a considerable time. Nevertheless, the operating experience gained to date also revealed two critical problems. On the one hand, even smallest leakages in sealing foils led to irreparable breakdowns. On the other hand, heat loss in the marginal areas was revealed as a key deficiency, preventing the technology from advancing towards global marketability. This study presents an experimental approach to address these two key issues in the field of seasonal energy storage. Two small-scale laboratory tests were carried out to test paraffin wax as a completely novel component in the marginal area of seasonal storages. This is based on two material properties: As hydrophobic and mobile medium, the warmed and molten paraffin should actively seal the fissures and holes in the event of leakage. Additionally, the latent heat storage properties of the paraffin wax should increase the systems’ total storage capacity and reduce lateral heat losses via its low thermal conductivity. With retardation periods from 2.5 to 4 hours, the results show an effective phase change effect of the paraffin wax, which reduces energy losses and allows to buffer short-term, intensive loading and unloading processes. By storing up to 138 kJ/kg energy in the paraffin wax, increased capacities of application-scale pit storages by up to 40.70 MWh are to be expected. Additionally, the self-healing features could be successfully demonstrated: With only small losses of between 1.5 and 17%, the paraffin wax effectively sealed artificially incised leaks. Thereby, the mechanism was most effective for local defects. Following these positive demonstrations of feasibility, technical design questions still remain, which concern prevention of deformation of the paraffin wax. Once solved, this new component can then provide a path for further optimization of seasonal heat storage technologies. UR - https://doi.org/10.1371/journal.pone.0236056 Y1 - 2020 UR - https://doi.org/10.1371/journal.pone.0236056 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-34535 SN - 1932-6203 VL - 15 IS - 7 PB - PLOS CY - San Francisco ER - TY - CHAP A1 - Mehta, Kedar ED - Motahhir, Saad ED - Bossoufi, Badre ED - Guerrero, Josep M. T1 - AI and ML Based Energy Management in Smart Grids with Renewable Integration T2 - Digital Technologies and Applications: Proceedings of ICDTA’25, Ifrane, Morocco. Volume 1 UR - https://doi.org/10.1007/978-3-032-07718-9_38 Y1 - 2026 UR - https://doi.org/10.1007/978-3-032-07718-9_38 SN - 978-3-032-07718-9 SP - 453 EP - 463 PB - Springer CY - Cham ER - TY - INPR A1 - Müller, Simon Nikolaus A1 - Schmitt, David A1 - Bott, Christoph A1 - Akbar, Shariq A1 - Bayer, Peter A1 - Schrag, Tobias T1 - Operating thermal source networks – How supply temperature and ground exchange shape performance T2 - SSRN UR - http://dx.doi.org/10.2139/ssrn.6034530 Y1 - 2026 UR - http://dx.doi.org/10.2139/ssrn.6034530 PB - Elsevier CY - Amsterdam ER - TY - CHAP A1 - Reum, Tobias A1 - Schmitt, David A1 - Summ, Thorsten A1 - Schrag, Tobias ED - Fink, Christian ED - Brunner, Christoph T1 - Energetic Potential of Parallel Operation of Two Heat Sources in a Dual-Source Heat Pump T2 - International Sustainable Energy Conference - Proceedings N2 - Dual-source heat pumps can mitigate disadvantages of single source heat pumps: They have fewer geological requirements compared to ground-source heat pumps while having higher efficiencies compared to air-source heat pumps. Parallel operation of two heat sources can also make electric heaters for peak loads obsolete, leading to economic benefits in the operational costs. Parallel operation has not been analysed thoroughly at different evaporation temperature gradients. To address this gap in research, four possible interconnections of two heat sources were analysed using a refrigerant cycle simulation, two with similar and two with separate evaporation pressures. The energetic potential of each interconnection is evaluated and compared to single source operation with an air-source and a ground-source heat pump. The results showed that only the interconnections with separate evaporation pressure allowed significant reduction in evaporation power from the ground source. As expected, the efficiency – compared to single air-source operation – increased for all parallel interconnections but decreased compared to ground-source operation. Efficient peak load coverage with small ground-source collectors therefore requires a more complex interconnection of completely split evaporator branches at different evaporation pressures. While the efficiency and heating power compared to single ground-source operation decreased slightly (by 4% and 6%, respectively), the power load on the GSHX and ASHX reduced to about 54% and 66% compared to the corresponding single-source operation, respectively. This allows high efficiency at reduced GSHX size and ASHX noise emission. Additionally, this interconnection also allows increased flexibility for improved heat source management. UR - https://doi.org/10.52825/isec.v1i.1158 Y1 - 2024 UR - https://doi.org/10.52825/isec.v1i.1158 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-58147 SN - 2976-2030 PB - TIB Open Publishing CY - Hannover ER - TY - CHAP A1 - Müller, Simon Nikolaus A1 - Strobel, Rainer A1 - Faigl, Markus A1 - Schrag, Tobias ED - Fink, Christian ED - Brunner, Christoph T1 - Analysis of Industrial 5GDHC System in Ingolstadt BT - A Step Towards CO2-Neutral Industry T2 - International Sustainable Energy Conference - Proceedings N2 - This study comprehensively examines the technical manifestation and planning process for a shared thermal energy network at a 75-hectare industrial area in Ingolstadt. Unlike traditional systems, this (5GDHC) network showcases a smart integration of energy flows across 70 buildings with a yearly heating demand of around 17 GWh and a yearly cooling demand of around 35 GWh. The network spans over 9,100 meters of piping with diameters up to 800 mm. With thermal power from various sources including 1.8 MW waste heat from a data centre and potential for 10 MW from the Danube River, the system epitomizes a dynamic balance of heating and cooling demands. The paper itself examines the planning process of the system and encompasses topics such as defining energy requirements and load profiles, assessing potential energy sources and sinks for enhanced system efficiency, and analysing pipe and network design. Through this investigation, the study provides valuable insights towards a methodology to facilitate the successful implementation of future industrial 5GDHC systems, furthering the cause of sustainable energy. UR - https://doi.org/10.52825/isec.v1i.1152 Y1 - 2024 UR - https://doi.org/10.52825/isec.v1i.1152 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-66874 SN - 2976-2030 PB - TIB Open Publishing CY - Hannover ER - TY - JOUR A1 - Emberger, Lukas A1 - Nair, Gireesh A1 - Lichtenegger, Klaus A1 - Moser, Maria A1 - Summ, Thorsten A1 - Natiesta, Thomas A1 - Fan, Jianhua A1 - Wang, Pengcheng A1 - Unterberger, Viktor A1 - Ohnewein, Philip T1 - Open data in the solar thermal community: Status, barriers, and opportunities JF - Solar Energy Advances N2 - Open data in the renewable energy sector could contribute to a greener future and reduce carbon emissions. This study investigates existing open datasets in the solar thermal domain, challenges in publishing and using open data and its potential impact. The results support the common belief that open data is useful, offering considerable benefits for data re-users and the solar thermal community. While substantial open data in the solar thermal domain already exists, some datasets like plant statistics and cost data are hard to utilize due to licensing, accessibility, and quality issues. The study shows that data owners benefit less from publishing data compared to data re-users and service providers. While data sharing seems appealing to data owners, several barriers discourage data sharing. Suggestions to promote the use and publications of open data in solar thermal domain are discussed. UR - https://doi.org/10.1016/j.seja.2025.100114 Y1 - 2025 UR - https://doi.org/10.1016/j.seja.2025.100114 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-66691 SN - 2667-1131 VL - 2025 IS - 5 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - James, Stuart Daniel A1 - Killinger, Markus A1 - Mutanga, Chiedza Ngonidzashe A1 - Pirard, Romain A1 - Einax, Mario A1 - Huber, Matthias A1 - Bader, Tobias T1 - The hybrid renewable energy community approach (HyRECA): Synergising electricity access with bush encroachment mitigation in rural Southern Africa JF - Renewable and Sustainable Energy Transition N2 - Rural electrification and bush encroachment in Southern Africa have long been studied separately. Research shows that hybrid renewable energy systems (HRES) offer viable solutions for off-grid communities, and bush encroachment mitigation is widely recognised as an ecological priority. Using Jamataka, Botswana, as a case study, this study integrates both, asking under which conditions encroacher bush-based HRES are economically viable, which electricity access levels local populations can afford, and whether biomass utilisation contributes to mitigation. Findings indicate strong potential for bush-based HRES in off-grid areas, but competitiveness declines where low-cost grid electricity is available. Economic viability is examined through levelised cost of electricity (LCOE) across alternative HRES configurations. HOMER Pro® simulations indicate PV/biomass/battery systems are most cost-effective off-grid, achieving 100 % renewable fractions, near zero CO₂ emissions, and LCOE of 0.246 $/kWh. In grid-connected contexts without feed-in, PV/diesel/grid combinations dominate (LCOE 0.117 $/kWh) due to low tariffs, but with higher emissions. A novel affordability analysis using household willingness to pay and the World Bank Multi-Tier Framework indicates that all households reach at least Tier 3 electricity access under grid-connected systems and >70 % off-grid, supporting household-use of medium-power appliances. Sustainable biomass extraction clears ∼12 ha annually (∼120 t) in Jamataka, aiding bush encroachment mitigation. Upscaling indicates potential to electrify 1.35 million people in >900 bush-encroached villages across Botswana, Namibia, and South Africa, using <1 % of encroached land – highlighting significant untapped potential. Future research should validate findings through geospatial modelling with high-resolution biomass data and spatially sensitive biomass cost models for region-wide planning. UR - https://doi.org/10.1016/j.rset.2025.100136 Y1 - 2025 UR - https://doi.org/10.1016/j.rset.2025.100136 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-66620 SN - 2667-095X VL - 2026 IS - 9 PB - Elsevier CY - Amsterdam ER - TY - INPR A1 - James, Stuart Daniel A1 - Killinger, Markus A1 - Mutanga, Chiedza Ngonidzashe A1 - Pirard, Romain A1 - Einax, Mario A1 - Huber, Matthias A1 - Bader, Tobias T1 - The Hybrid Renewable Energy Community Approach (HyRECA): Synergising energy access, economic development, and ecosystem restoration in rural Southern Africa T2 - SSRN UR - https://dx.doi.org/10.2139/ssrn.5294413 Y1 - 2025 UR - https://dx.doi.org/10.2139/ssrn.5294413 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Ngetuny, Joshua Kiplagat A1 - Baldauf, Tobias A1 - Zörner, Wilfried T1 - Evaluating Feedstock Pretreatment Methods to Unlock Co-Digestion in Small-Scale Biogas Systems: A Multi-Criteria Approach to System Integration and Decision Making JF - Energies N2 - Small-scale biogas plants in developing countries present a viable alternative to traditional polluting energy sources, particularly in rural and underserved communities. These systems typically rely on locally sourced livestock manure; however, inconsistent supply often results in underfeeding, reduced biogas production, and, in many cases, system abandonment. Co-digestion with crop residues presents a promising strategy to enhance feedstock availability and system resilience. However, the recalcitrant nature of lignocellulosic biomass and limited access to suitable pretreatment technologies have constrained its adoption. This paper evaluates feasible pretreatment methods for integrating crop residues, especially straw, into small-scale biogas systems. Using the Analytic Hierarchy Process (AHP), pretreatment methods are assessed based on five criteria: (i) technology simplicity, (ii) energy requirements, (iii) capital and operational costs, (iv) effectiveness, and (v) environmental impact. The analysis identifies microbial pretreatment using the liquid fraction of digestate, combined with mechanical size reduction, as the most suitable approach for small-scale implementation, utilizing low-cost, simplified mechanical devices adaptable to various crop residues with minimal energy input. A conceptual design of a demonstration plant is proposed to validate this integrated pretreatment approach and assess its impact on biogas yield, system performance, and technology adoption. The design incorporates an on-site digestate separation unit to supply microbial inoculum and emphasizes simplicity and cost-effectiveness in material handling and energy use. Pilot trials are proposed to evaluate key performance indicators, including specific methane yield (LCH4/gVS added), volatile solids reduction (%), and methane content increase (%), ensuring evidence-based adoption and practical applicability of the design. UR - https://doi.org/10.3390/en19051303 Y1 - 2026 UR - https://doi.org/10.3390/en19051303 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-67479 SN - 1996-1073 VL - 19 IS - 5 PB - MDPI CY - Basel ER - TY - JOUR A1 - Ngetuny, Joshua Kiplagat A1 - Baldauf, Tobias A1 - Zörner, Wilfried T1 - Optimizing Feedstock Selection for Sustainable Small-Scale Biogas Systems Using the Analytic Hierarchy Process JF - Energies N2 - Small-scale biogas systems can play a pivotal role in sustainable energy provision, particularly in developing countries. However, their dependence on livestock manure as the only feedstock poses challenges to their adoption and long-term viability. This often leads to insufficient biogas production and plant abandonment. This study proposes co-digestion of livestock manure with other farm residues to enhance the technical sustainability of small-scale biogas systems by ensuring adequate and consistent biogas production throughout the plant’s lifespan, minimizing the risks associated with reliance on a single feedstock. A novel feedstock selection approach is developed using the Analytic Hierarchy Process (AHP), a multicriteria decision-making method, to prioritize feedstocks based on adequacy, supply consistency, and logistical ease. AHP is chosen due to its capability to handle both quantitative and qualitative evaluation criteria. This approach is applied to the Fès-Meknès region of Morocco, which offers abundant livestock and crop residues alongside product utilization pathways. The prioritization and ranking of the potential feedstocks identified in the region reveals cattle manure as the top-ranked feedstock due to its consistent supply and ease of collection, followed by straw, valued for its storability and nutrient stability. Sheep, horse, and chicken manure ranked third, fourth, and fifth, respectively, while household food waste and fruit and vegetable residues, limited by seasonality and perishability, were ranked lower. Based on these findings, co-digestion of cattle manure and straw is proposed as a sustainable strategy for small-scale biogas plants in Fès-Meknès, addressing feedstock shortages, enhancing biogas production, and reducing plant abandonment. This approach strengthens technical sustainability and promotes the broader adoption of biogas technologies in developing countries. UR - https://doi.org/10.3390/en18071739 Y1 - 2025 UR - https://doi.org/10.3390/en18071739 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-57915 SN - 1996-1073 VL - 18 IS - 7 PB - MDPI CY - Basel ER - TY - JOUR A1 - Ngetuny, Joshua Kiplagat A1 - Hsaine, Jalal A1 - Mabrouki, Abdelaalim A1 - Rachidi, Fouad A1 - El Asli, Abdelghani A1 - Zörner, Wilfried T1 - Assessment of agricultural residues for small-scale biogas plants and adoption drivers: a case study of the Fès-Meknès region in Morocco JF - Biomass Conversion and Biorefinery N2 - Small-scale biogas systems hold promise as reliable renewable energy sources in developing nations; however, adequate and consistent supply of feedstock remains a challenge. Agricultural residue, due to their lack of competition with food crops for resources, is touted as a dependable feedstock choice. This article therefore examines agricultural residues as potential biogas plant feedstocks in the Fès-Meknès region of Morocco, using a structured farm survey to evaluate livestock types, crop varieties, and residue utilization. Additionally, the study explores the challenges and drivers influencing biogas technology adoption in Morocco. Findings indicate a predominance of small-scale farms with livestock (averaging 11 cattle, 45 sheep, and 20 chicken) and mainly subsistence crop production, making these farms suitable candidates for small-scale biogas plants. Key barriers to adoption include a lack of awareness about the technology, along with technical and financial constraints. However, raising awareness, establishing demonstration plants, and offering financial and non-financial incentives are identified as potential drivers of adoption. This research provides a foundation for implementing biogas technologies in the case study area and other developing nations, guiding researchers and governmental and non-governmental organizations in disseminating small-scale biogas systems as a reliable energy source and a method for converting agricultural residues into sustainable energy (biogas) and fertilizer. Graphical Abstract UR - https://doi.org/10.1007/s13399-024-06443-y Y1 - 2025 UR - https://doi.org/10.1007/s13399-024-06443-y UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-55523 SN - 2190-6815 VL - 15 IS - 22 SP - 29207 EP - 29223 PB - Springer CY - Berlin ER -