@article{LwakatareVyavahareMehtaetal.2024, author = {Lwakatare, Bertha and Vyavahare, Priyanka and Mehta, Kedar and Z{\"o}rner, Wilfried}, title = {Electrification Planning for Off-Grid Communities in Sub-Saharan Africa: Advancing Energy Access}, volume = {17}, pages = {5994}, journal = {Energies}, number = {23}, publisher = {MDPI}, address = {Basel}, issn = {1996-1073}, doi = {https://doi.org/10.3390/en17235994}, year = {2024}, abstract = {Sub-Saharan Africa, especially its rural areas, faces significant challenges in achieving universal electrification despite its abundant renewable energy resources. The region has the highest population without access to electricity, largely due to economic, infrastructural, and geographical barriers. Energy poverty is a critical issue that hinders sustainable development and exacerbates inequalities. Namibia's sustainable energy policy aligns with the global Sustainable Development Goals (SDGs), particularly SDG 7, which aims to provide affordable and reliable modern energy access for all. The policy emphasizes mini-grids and decentralized power systems as key strategies for rural electrification. However, despite increased deployment of mini-grids, these solutions often struggle with long-term sustainability. This research explores cost-effective electrification strategies through scenario-based modeling to reduce energy poverty and expand energy access in Namibia's rural communities, focusing on the existing mini-grids in Tsumkwe and Gam. Using a comprehensive methodology that incorporates HOMER Pro for mini-grid capacity expansion and MS Excel for evaluating main-grid extensions, this study aims to identify the most feasible and economical electrification solutions. The analysis compares electricity supply, total net present cost, and the levelized cost of electricity across these systems. The findings will offer insights into addressing energy poverty in Namibia and provide recommendations for sustainable and scalable rural electrification across Sub-Saharan Africa.}, language = {en} } @article{MirzaqobulovMehtaIlyasetal.2024, author = {Mirzaqobulov, Jakhongirmirzo and Mehta, Kedar and Ilyas, Sana and Salokhiddinov, Abdulkhakim}, title = {The Role of Collector-Drainage Water in Sustainable Irrigation for Agriculture in the Developing World: An Experimental Study}, volume = {6}, journal = {World}, number = {1}, publisher = {MDPI}, address = {Basel}, issn = {2673-4060}, doi = {https://doi.org/10.3390/world6010001}, year = {2024}, abstract = {This study investigates the feasibility of using mineralized collector-drainage water (CDW) for irrigating maize crops on light gray soils in the Syrdarya region of Uzbekistan, an area facing severe water scarcity and soil salinity challenges. The research is particularly novel as it explores maize production in marginalized soils, a subject previously unexamined in this context. The experiment was designed as a three-factor factorial study with three replications, following the guidelines of the Uzbekistan Cotton Scientific Research Institute. Five irrigation treatments (Fresh Water, Fresh Water 70\% vs. CDW 30\%, Complex Method (Mixing with Specific Rules), CDW 70\% vs. Fresh Water 30\% (Mixing) and only CDW) were evaluated using an Alternate Furrow Irrigation system, incorporating various mixtures of fresh water and CDW to determine their effects on soil salinity, crop health and yield. The amount of irrigation water required was determined using a soil moisture balance model, with soil samples collected at multiple depths (0-100 cm) to monitor changes in moisture content and salinity. Salinity levels and soil health parameters such as alkalinity, chloride, sulfate and cation/anion balances were measured at different stages of crop growth. Data were collected over three growing seasons (3 years). An analysis of the data revealed that using CDW, even in mixtures with fresh water, can sustain crop production while managing soil salinity. Notably, irrigation methods such as Mixing 70-30 and the Complex Mixing Method effectively reduced freshwater dependency and maintained the crop yield without significantly increasing salinity. The results suggest that CDW could be a viable alternative water source in regions where traditional water resources are limited. The findings have significant implications for improving water use efficiency and agricultural productivity in areas facing similar environmental challenges. This research not only contributes to the broader understanding of sustainable irrigation practices in arid regions but also provides a scientific basis for the wider adoption of CDW in Uzbekistan, potentially enhancing food security and supporting long-term agricultural sustainability in the region.}, language = {en} } @article{MehtaZoerner2023, author = {Mehta, Kedar and Z{\"o}rner, Wilfried}, title = {Cracking the code: mapping residential building energy performance in rural Central Asia through building typologies}, volume = {5}, pages = {349}, journal = {SN Applied Sciences}, number = {12}, publisher = {Springer Nature}, address = {Cham}, issn = {2523-3971}, doi = {https://doi.org/10.1007/s42452-023-05607-1}, year = {2023}, abstract = {Buildings in rural Central Asia have unique characteristics as they were built during the Soviet era (during 1950-1960) without any energy efficiency measures. The special and aged building stock pose a crucial challenge on energy security and energy supply. However, accurate scientific data on their energy usage is lacking, highlighting a research gap about robust and validated methodology to determine the energy use of rural Central Asian buildings. In response to this need, this research paper proposes a set of generalised residential building typologies for rural Central Asia, with a focus on Kyrgyzstan. The study combines quantitative and qualitative methods, including household surveys, energy demand modelling, EnergyPlus simulations, and result validation. It derives energy-based building typologies from construction year and building envelope characteristics. Through numerous validated simulations, it was identified that the heat demand for rural Kyrgyz houses is 3-5 times here compared to European houses (250-400 kWh/m2). The study revealed the estimated heat demand for homes in rural Kyrgyzstan, indicating a significant potential for improving building energy efficiency in the region. These results can inform specific approaches, such as building renovation plans, energy certification, and renovation strategies. Furthermore, the validated methodology introduced offers opportunities for researchers in the field of building energy efficiency and can be applied to similar regions in Central Asia with comparable building stocks and climates.}, language = {en} } @article{SummOyinlolaKhattaketal.2023, author = {Summ, Thorsten and Oyinlola, Muyiwa and Khattak, Sanober and Trinkl, Christoph and Z{\"o}rner, Wilfried}, title = {Statistical analysis of solar thermal collectors in the Solar Keymark Database}, volume = {2024}, pages = {103581}, journal = {Sustainable Energy Technologies and Assessments}, number = {61}, publisher = {Elsevier}, address = {Amsterdam}, issn = {2213-1396}, doi = {https://doi.org/10.1016/j.seta.2023.103581}, year = {2023}, abstract = {Experimental, analytical, or numerical investigations are ordinarily conducted to reveal optimisation potential for solar thermal collectors. At the same time, the 'Solar Keymark Database' contains more than 2,000 test reports from certified laboratories featuring properties including thermal efficiency, dimensions, or optical properties. This dataset offers untapped potential for statistical analyses as an alternative optimisation approach. Hence, this paper aims to provide a) the first statistical findings of solar thermal collector properties listed in the Solar Keymark Database and b) insights into statistical relations between these properties. The key correlations observed from the analysis of flat-plate collectors were between efficiency and both gross height (R = 0.30) and gross area (R = 0.27). We concluded that preferable collector designs may be featured with larger area to height ratios. The analyses of evacuated tube collectors revealed a strong correlation between efficiency and transversal incidence angle modifier (R = -0.65) as a result from different tube spacing. It was noticeable that the quasi-dynamic test method reported significantly higher efficiencies (7.14 percentage points) for evacuated tube collectors, which should be carefully considered for future test procedures. Overall, the statistical analysis was in accordance with conventional bottom-up analyses and revealed insightful dependencies for the present collector data.}, language = {en} } @article{MehtaZoerner2025, author = {Mehta, Kedar and Z{\"o}rner, Wilfried}, title = {Crop selection in Agri-PV: international review based strategic decision-making model}, volume = {2025}, pages = {100143}, journal = {Solar Compass}, number = {16}, publisher = {Elsevier}, address = {Amsterdam}, issn = {2772-9400}, doi = {https://doi.org/10.1016/j.solcom.2025.100143}, year = {2025}, abstract = {Agri-Photovoltaics (Agri-PV) is well known for its dual land use, integrating solar energy generation with agricultural production. This not only optimizes land use but also enhances food and energy security. Since Agri-PV is closely linked with crop cultivation, it is not solely about energy generation but also requires careful consideration of crop suitability within Agri-PV installations. Despite its significance, there is limited information available to guide decision-making for crop selection in Agri-PV systems. Selecting suitable crops remains a complex challenge, as factors such as shading tolerance, water requirements, and economic viability vary across different geographical and climatic conditions. This study develops a novel, review-based decision support model for crop selection in Agri-PV systems, synthesizing international research and case studies to provide a structured framework for decision-making. The model is based on 12 main crop typologies and key parameters such as water use, shading adaptability, crop yield/economic potential, and space requirements, derived from 117 research articles and case studies from 25 countries. By leveraging insights from successful international implementations, the model provides a practical framework for policymakers, farmers, and energy planners to enhance the sustainability and efficiency of Agri-PV projects. Findings suggest that crop selection strategies must align with regional climate conditions and PV system design to maximize synergies between energy and food production. High-value crops that require less space and have higher shade tolerance are more suitable for small-scale or decentralized Agri-PV systems. Future research should focus on advanced modeling techniques, AI-driven optimization, and real-world pilot studies to further refine decision-making in Agri-PV deployment. This study contributes to the growing body of knowledge on Agri-PV systems by providing a novel crop suitability matrix for effective decision-making.}, language = {en} } @article{VannahmePatelSchmittetal.2024, author = {Vannahme, Anna and Patel, Dharmik and Schmitt, David and Summ, Thorsten and Trinkl, Christoph and Schrag, Tobias}, title = {Technical and economic analysis of digitally controlled substations in local district heating networks}, volume = {2024}, pages = {133585}, journal = {Energy}, number = {312}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0360-5442}, doi = {https://doi.org/10.1016/j.energy.2024.133585}, year = {2024}, abstract = {Since the 1990s, there has been a noticeable increase in the establishment of local district heating networks in Germany, coinciding with the use of thermal energy from biogas and biomass facilities. Historically, the prioritization of economically efficient heat utilization was subdued due to favorable electricity feed-in tariffs. However, with the expiration of Renewable Energy Sources Act subsidies, operators shifted focus to the operational costs of district heating networks. This study aims to examine the effects of optimizing controllers and valves at district heating substations in single-family homes, utilizing two local district heating networks. The emphasis is on evaluating impacts on operating costs and determining whether the economic and energetic benefits justify implementation. Simulation studies in MATLAB/Simulink Simscape depict both consumers and district heating networks individually, without aggregation. In the most favorable scenario, investing in enhancing substation controllers in single-family homes is projected to yield returns after 13 years. Comprehensive optimization of all substation controls in single-family homes can potentially result in up to 9\% savings in thermal energy demand due to reduced heat losses and a corresponding 9\% reduction in electrical power consumption for the main pump.}, language = {en} } @article{TutunaruBoschGresshakeetal.2023, author = {Tutunaru, Robin and Bosch, Stephan and Greßhake, Lukas and Holzhammer, Uwe}, title = {Ein Konzept f{\"u}r eine GIS-gest{\"u}tzte Visualisierung der spezifischen Anforderungen von regionalen Akteuren der Energiewende an die Landnutzung}, volume = {2023}, journal = {AGIT: Journal f{\"u}r Angewandte Geoinformatik}, number = {9}, publisher = {Wichmann Verlag}, address = {Berlin}, issn = {2509-713X}, doi = {https://doi.org/10.14627/537742005}, pages = {44 -- 49}, year = {2023}, abstract = {F{\"u}r eine nachhaltige Energiewende werden Konzepte ben{\"o}tigt, welche die techno-{\"o}konomische und sozial-{\"o}kologische Komplexit{\"a}t regionaler Standortentscheidungen f{\"u}r erneuerbare Energien (EE) visualisieren k{\"o}nnen. Dabei m{\"o}chten wir die Ergebnisse mittels Geographischer Infor-mationssysteme (GIS) so visualisieren, dass sie von jedem Akteur nachvollzogen werden k{\"o}nnen und einen konstruktiven Austausch zur Wertigkeit bestimmter Fl{\"a}chen zwischen allen Akteuren erlauben.}, language = {de} } @inproceedings{MastHuemmerHolzhammer2022, author = {Mast, Tanja and H{\"u}mmer, Benedikt and Holzhammer, Uwe}, title = {Smart Markets als marktbasierte Erg{\"a}nzung zum deutschen Engpassmanagement}, booktitle = {17. Symposium Energieinnovation}, subtitle = {Konzeptionierung anhand eines Modellbeispiels}, publisher = {Technische Universit{\"a}t Graz}, address = {Graz}, url = {https://www.tugraz.at/events/eninnov2022/nachlese/download-beitraege/stream-a/\#c318498}, year = {2022}, language = {de} } @article{StoecklHolzhammer2024, author = {St{\"o}ckl, Martin and Holzhammer, Uwe}, title = {Integration von Flexibilit{\"a}t in die Energieversorgung}, volume = {35}, journal = {Ern{\"a}hrung aktuell - der Lebensmittelbrief}, subtitle = {Ein Aspekt zur Erreichung der Klimaziele und zur Stabilisierung der Energiekosten - Fallbeispiel K{\"u}hlhaus}, number = {Mai/Juni}, publisher = {LID}, address = {Lampertheim}, issn = {1866-6787}, pages = {46 -- 47}, year = {2024}, language = {de} } @inproceedings{MastHuemmerHolzhammer2021, author = {Mast, Tanja and H{\"u}mmer, Benedikt and Holzhammer, Uwe}, title = {Potential of Demand Side Management and Biogas Plants in regional market-based Congestion Management}, booktitle = {ENERDAY 15th Conference on Energy Economics and Technology "Creative Destruction? Disruptive innovation in times of Covid and an accelerated energy system transformation": Book of Abstracts}, publisher = {TU Dresden}, address = {Dresden}, url = {https://tu-dresden.de/bu/wirtschaft/bwl/ee2/tagungen/enerday-archives}, pages = {22 -- 23}, year = {2021}, language = {en} } @article{DoepfertChuHamacher2025, author = {Doepfert, Markus and Chu, Jiahe and Hamacher, Thomas}, title = {HAMLET: A modular agent-based Python framework for energy markets and systems}, volume = {2025}, pages = {102346}, journal = {SoftwareX}, number = {32}, publisher = {Elsevier}, address = {Amsterdam}, issn = {2352-7110}, doi = {https://doi.org/10.1016/j.softx.2025.102346}, year = {2025}, abstract = {HAMLET is an agent-based Python framework designed to model the intricate interactions between energy markets, systems, and stakeholders. Its modular architecture provides a flexible and adaptable platform for analyzing complex energy systems. With numerous pre-built templates for energy system components, HAMLET enables researchers to focus on their area of expertise without the need to develop the surrounding ecosystem from scratch. By integrating market and system dynamics, HAMLET supports diverse applications, including market design optimization, grid management, policy refinement, and energy management system development. HAMLET delivers detailed insights into the technical, economic, and social impacts of new system designs, addressing a critical gap in energy system modeling.}, language = {en} } @article{ChaturvediKumarToftumetal.2025, author = {Chaturvedi, Pushpendra Kr. and Kumar, Nand and Toftum, J{\o}rn and Andersen, Rune Korsholm and Lamba, Ravita and Mehta, Kedar}, title = {Exploring influential parameters affecting residential building energy use: advancing energy efficiency through machine learning}, volume = {27}, journal = {Clean Technologies and Environmental Policy}, number = {11}, publisher = {Springer}, address = {Berlin}, issn = {1618-9558}, doi = {https://doi.org/10.1007/s10098-025-03301-x}, pages = {6975 -- 6996}, year = {2025}, language = {en} }