@article{LehnaSchellerHerwartz, author = {Lehna, Malte and Scheller, Fabian and Herwartz, Helmut}, title = {Forecasting day-ahead electricity prices: A comparison of time series and neural network models taking external regressors into account}, series = {Energy Economics}, volume = {106}, journal = {Energy Economics}, issn = {1873-6181}, doi = {10.1016/j.eneco.2021.105742}, pages = {105742 -- 105742}, abstract = {The amount of renewable energies in electricity production has increased significantly in the last decade, resulting in more variability of the day-ahead electricity spot price. The Electricity Price Forecast (EPF) has to adapt to the new situation by applying flexible models. However, the numerous available forecasting methods differ widely, with no distinct candidate offering the best solution. Against this background, we conduct a comparative study of four different approaches to forecasting the German day-ahead electricity spot price. In addition to the prominent Seasonal Integrated Auto-Regressive Moving Average model ((S)ARIMA(X)) and the Long-Short Term Memory (LSTM) neural network models, we employ a Convolutional Neural Network LSTM (CNN-LSTM) and an extended two-stage multivariate Vector Auto-Regressive model (VAR) approach as hybrid models. For better performance, we include common external influences such as the consumer load, fuel and emission prices, average solar radiation and wind speed in our analysis. We analyse hourly data for twelve samples from October 2017 to September 2018. Each model is implemented to deliver price forecasts at three horizons, i.e., one day, seven days and thirty days ahead. While the LSTM model achieves the best forecasting performance on average, the two-stage VAR follows closely behind and performs exceedingly well for shorter prediction horizons. Further, we provide evidence that a combination of both forecasting methods outperforms each of the single models. This indicates that combining advanced methods could lead to further improvements in electricity spot price forecasts.}, language = {en} } @inproceedings{MaheriBagaliChilaketal., author = {Maheri, A. and Bagali, R. and Chilak, C. and Scheller, Fabian and Mustafa, A. I.}, title = {Deterministic versus nondeterministic design of hybrid renewable energy systems}, series = {2nd International Symposium On Environment Friendly Energies And Applications}, booktitle = {2nd International Symposium On Environment Friendly Energies And Applications}, isbn = {978-1-4673-2911-8}, doi = {10.1109/efea.2012.6294064}, pages = {212 -- 217}, abstract = {The performance of the deterministic design methods in design of reliable and cost effective standalone hybrid renewable energy systems is evaluated. Reliability in the power supply is the chief feature of a standalone hybrid renewable energy system. It is shown that the traditional methods of considering the effect of uncertainties in deterministic designs such as design for worst case scenarios and employing safety measures such as margin of safety have little impact on the actual reliability of the designed system.}, language = {en} } @article{GunkelBergaentzleGrastedJensenetal., author = {Gunkel, Philipp Andreas and Bergaentzl{\´e}, Claire and Gr{\ae}sted Jensen, Ida and Scheller, Fabian}, title = {From passive to active: Flexibility from electric vehicles in the context of transmission system development}, series = {Applied Energy}, volume = {277}, journal = {Applied Energy}, issn = {1872-9118}, doi = {10.1016/j.apenergy.2020.115526}, pages = {115526 -- 115526}, abstract = {Electrification of transport in RES-based power system will support the decarbonisation of the transport sector. However, due to the increase in energy demand and the large peak effects of charging, the passive integration of electric cars is likely to undermine sustainability efforts. This study investigates three different charging strategies for electric vehicle in Europe offering various degrees of flexibility: passive charging, smart charging and vehicle-to-grid, and puts this flexibility in perspective with the flexibility offered by interconnections. We use the Balmorel optimization tool to represent the short-term dispatch and long-term investment in the energy system and we contribute to the state-of-the-art in developing new methodologies to represent home charging and battery degradation. Our results show how each step of increased charging flexibility reduces system costs, affects energy mix, impacts spot prices and reduces CO2 emissions until the horizon 2050. We quantify how flexible charging and variable generation mutually support each other (>100 TWh from wind and solar energy in 2050) and restrict the business case for stationary batteries, whereas passive charging results in a substitution of wind by solar energy. The comparison of each charging scheme with and without interconnection expansion highlights the interplay between European countries in terms of electricity prices and CO2 emissions in the context of electrified transport. Although the best outcome is reached under the most flexible scenario at the EU level, the situation of the countries with the cheapest and most decarbonised electricity mix is damaged, which calls for adapted coordination policy at the EU level.}, language = {en} } @article{WeinandSchellerMcKenna, author = {Weinand, Jann Michael and Scheller, Fabian and McKenna, Russell}, title = {Reviewing energy system modelling of decentralized energy autonomy}, series = {Energy}, volume = {203}, journal = {Energy}, issn = {1873-6785}, doi = {10.1016/j.energy.2020.117817}, pages = {117817 -- 117817}, abstract = {Research attention on decentralized autonomous energy systems has increased exponentially in the past three decades, as demonstrated by the absolute number of publications and the share of these studies in the corpus of energy system modelling literature. This paper shows the status quo and future modelling needs for research on local autonomous energy systems. A total of 359 studies are investigated, of which a subset of 123 in detail. The studies are assessed with respect to the characteristics of their methodology and applications, in order to derive common trends and insights. Most case studies apply to middle-income countries and only focus on the supply of electricity in the residential sector. Furthermore, many of the studies are comparable regarding objectives and applied methods. Local energy autonomy is associated with high costs, leading to levelized costs of electricity of 0.41 \$/kWh on average. By analysing the studies, many improvements for future studies could be identified: the studies lack an analysis of the impact of autonomous energy systems on surrounding energy systems. In addition, the robust design of autonomous energy systems requires higher time resolutions and extreme conditions. Future research should also develop methodologies to consider local stakeholders and their preferences for energy systems.}, language = {en} } @article{KondziellaSpechtLerchetal., author = {Kondziella, Hendrik and Specht, Karl and Lerch, Philipp and Scheller, Fabian and Bruckner, Thomas}, title = {The techno-economic potential of large-scale hydrogen storage in Germany for a climate-neutral energy system}, series = {Renewable and Sustainable Energy Reviews}, volume = {182}, journal = {Renewable and Sustainable Energy Reviews}, issn = {1364-0321}, doi = {10.1016/j.rser.2023.113430}, pages = {113430 -- 113430}, abstract = {The seasonal storage of natural gas is a recognized and reliable technology in the energy industry. Salt caverns are particularly suitable for storing alternative gaseous fuels such as hydrogen. Germany has a great technical potential for expanding its cavern storage capacity, which exceeds the expected demand for hydrogen many times. Regarding the projected long-term decline in natural gas use, the question arises as to whether existing caverns can meet future storage requirements. To this end, a techno-economic model is presented to meet electricity and hydrogen demand in a cost-optimal solution. This analysis focused on the utilization of hydrogen storage in terms of energy throughput and maximum storage capacity. To link the outcome of economic dispatch to the literature, the fundamental assumptions are based on comprehensive capacity expansion models. This study advances the state of the art by evaluating key input parameters of the future energy system. By conducting 192 model runs, the analysis revealed the range of uncertainty in terms of storage use. This indicates a strong dependence of the systemic and economic value of hydrogen storage on boundary conditions such as a consideration of dark doldrums, a flexible hydrogen demand profile, hydrogen import restrictions and a larger electrolyzer capacity. The uncertainty ranged from 0 to 67 TWhH2 for the storage capacity, with an average of 36.6 TWhH2 across all scenarios, and from 0 to 190 TWhH2 for the annual energy throughput. These results are significant for gas storage operators who derive transformation strategies and policymakers evaluating financial funding requirements.}, language = {en} } @article{SchellerWaldKondziellaetal., author = {Scheller, Fabian and Wald, Stefan and Kondziella, Hendrik and Gunkel, Philipp Andreas and Bruckner, Thomas and Keles, Dogan}, title = {Future role and economic benefits of hydrogen and synthetic energy carriers in Germany: a review of long-term energy scenarios}, series = {Sustainable Energy Technologies and Assessments}, volume = {56}, journal = {Sustainable Energy Technologies and Assessments}, issn = {22131388}, doi = {10.1016/j.seta.2023.103037}, pages = {103037 -- 103037}, abstract = {Determining the development of Germany's energy system is the subject of a series of studies. Since their results play a significant role in the political energy debate for understanding the role of hydrogen and synthetic energy carriers, a better discussion is needed. This article provides an assessment of published transition pathways for Germany to assess the role and advantages of hydrogen-based carriers. Twelve energy studies including 37 scenarios for the years 2030 and 2050 were evaluated. Despite the variations, the carrier will play an important role. While their deployment is expected to have only started by 2030 with a mean demand of 91 TWh/a (4\% of the final energy demand) in Germany, they will be an essential part by 2050 with a mean demand of 480 TWh/a (24\%). The outcome of the scenarios depends on the chosen methods and assumptions. A moderately positive correlation (0.53) between the decarbonisation targets and the share of hydrogen-based carriers in final energy demand underlines the relevance for reaching the climate targets. Additionally, value creation effects of about 16 billion EUR/a in 2050 can be expected for hydrogen-based carriers. Hydrogen is expected to be produced domestically while synthetic fuels are projected to be mostly imported.}, language = {en} } @inproceedings{SpechtKondziellaBruckneretal., author = {Specht, Karl and Kondziella, Hendrik and Bruckner, Thomas and Scheller, Fabian}, title = {Scenarios for the decarbonization of district heating: the case of Leipzig}, series = {2023 19th International Conference on the European Energy Market (EEM)}, booktitle = {2023 19th International Conference on the European Energy Market (EEM)}, isbn = {979-8-3503-1258-4}, doi = {10.1109/eem58374.2023.10161822}, pages = {1 -- 11}, abstract = {This study derives the levelized cost of heat (LCOH) for exemplary post-fossil district heating (DH) scenarios. The DH system of Leipzig in 2040 under the assumption of a completely climate-neutral heat supply is considered. Accordingly, four generation scenarios (GS) are proposed based on different energy carriers that are characterized as follows: (1) natural gas with carbon capture and storage, (2) hydrogen, (3) diversified mix of biomass, waste heat and solar, and (4) electricity. In addition, the scenarios' robustness toward commodity prices is investigated using a sensitivity analysis. A modeling environment was used to optimize the hourly economic dispatch. Based on this, levelized costs are determined. For the reference case, the LCOH of the GS 1 and 2 exceeds the LCOH of GS 3 and 4. Furthermore, the results indicate that relying on singular energy carriers as opposed to diversified generation portfolios leads to less robust LCOH regarding price sensitivities.}, language = {en} } @article{HermannKachirayilLohrmannetal., author = {Hermann, Julian and Kachirayil, Febin and Lohrmann, Alena and Scheller, Fabian and Roskosch, Dennis and McKenna, Russell}, title = {A critical reflection on modelling approaches for heat pumps and building envelope retrofits in local energy system optimisations}, series = {Applied Energy}, volume = {400}, journal = {Applied Energy}, publisher = {Elsevier BV}, issn = {0306-2619}, doi = {https://doi.org/10.1016/j.apenergy.2025.126525}, abstract = {Integrating heat pumps and adopting building envelope retrofit (BER) measures is vital for decarbonising the built environment. This paper systematically reviews modelling approaches for these technologies within 84 local energy system optimisation studies. Our findings show that most studies simplify heat pump operation using a constant coefficient of performance (COP), perfect modulation, or a fixed heating capacity. While existing methods account for temperature-dependent COPs, only a few studies include more advanced approaches considering additional impacts. Two main approaches for modelling BER measures are identified: pre-defined retrofit sets with exogenous heat demand or an integrated retrofit selection with endogenous heat demand. While the pre-defined approach offers lower computational effort, it limits the BER solution space. The integrated approach achieves the opposite: a wider solution space but higher complexity. Moreover, only two studies consider the impact of BER measures on the heat supply temperature, an essential link between retrofit measures and heat pump efficiency. Based on our qualitative review, we derive recommendations for energy system modellers. For modelling heat pumps, we recommend using a temperature-dependent COP and heating capacity, as well as a lower modulation limit. Regarding BER measures, the integrated approach should be used for smaller scales (single buildings) while the pre-defined sets are suitable for larger scales. Finally, we propose a research agenda to address limitations and gaps in the current modelling approaches, such as addressing the performance gap between existing COP estimations and heat pump field performance and including a more detailed method for the heat supply temperature.}, language = {en} } @article{SiddiqueKelesSchelleretal., author = {Siddique, Muhammad Bilal and Keles, Dogan and Scheller, Fabian and Nielsen, Per Sieverts}, title = {Dispatch strategies for large-scale heat pump based district heating under high renewable share and risk-aversion: A multistage stochastic optimization approach}, series = {Energy Economics}, volume = {136}, journal = {Energy Economics}, doi = {10.1016/j.eneco.2024.107764}, pages = {107764 -- 107764}, language = {en} } @article{BreitschopfKeilBurghardetal., author = {Breitschopf, Barbara and Keil, Julia and Burghard, Uta and Scheller, Fabian}, title = {Forms of financial participation and acceptance of the energy transition-are there any relations?}, series = {Zeitschrift f{\"u}r Energiewirtschaft}, volume = {48}, journal = {Zeitschrift f{\"u}r Energiewirtschaft}, number = {1}, doi = {10.1007/s12398-024-1256-6}, pages = {38 -- 57}, language = {en} } @article{MorrisseyScheller, author = {Morrissey, Karyn and Scheller, Fabian}, title = {It takes a village: the role of community attributes in shaping solar photovoltaic adoption intention in Germany}, series = {Renewable Energy}, journal = {Renewable Energy}, doi = {10.1016/j.renene.2024.121542}, pages = {121542 -- 121542}, language = {en} } @article{Scheller, author = {Scheller, Fabian}, title = {The future demand of renewable fuels in Germany - Understanding the impact of electrification levels and socio-economic developments}, series = {Heliyon}, volume = {9}, journal = {Heliyon}, number = {11}, publisher = {Elsevier}, doi = {10.1016/j.heliyon.2023.e22271}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:863-opus-53637}, pages = {16}, abstract = {The Climate Change Act recently enacted in Germany highlights the urgency of understanding the future demand for renewable fuels. In this study, we combine technological progress and socio-economic pathways in an energy system analysis to assess future renewable fuel demands in Germany. We apply the whole-system optimisation model, TIMES, to investigate transition pathways with varying electrification levels and socio-economic developments. The results show that renewable fuels demand varies between 388 PJ and 1310 PJ depending on the electrification rates. Furthermore, our findings demonstrate that considering socio-economicaspects and behavioural change, as represented by different Shared-Socio-economic Pathways, can significantly alter the demand for renewable fuels within a narrower yet still noteworthy range compared to the electrification scenarios. This provides country-level evidence highlighting the often-overlooked influence of social developments on demand projections. Consequently, it becomes crucial to prioritize the consideration of the climate mitigation potential arising fromsocioeconomic-induced changes in demand patterns within the broader framework of energyefficiency measures.}, language = {en} } @inproceedings{LerchSchellerBruckner, author = {Lerch, Philipp and Scheller, Fabian and Bruckner, Thomas}, title = {Potential of demand response for chlor-alkali electrolysis processes}, series = {19th International Conference on the European Energy Market (EEM)}, booktitle = {19th International Conference on the European Energy Market (EEM)}, isbn = {979-8-3503-1258-4}, doi = {10.1109/eem58374.2023.10161892}, pages = {1 -- 7}, abstract = {Chlor-alkali electrolysis indicates significant demand response potential, accounting for over 2\% of Germany's total electricity demand. To fully analyze this potential, digital models or digital twins are necessary. In this study, we use the IRPopt modeling framework to develop a digital model of an electrolysis process and examine the cost-optimal load shifting application in the day-ahead spot and balancing reserve market for various price scenarios (2019, 2030, 2040). We also investigate the associated CO 2 emissions. Combined optimization at both markets results in greater and more robust cost savings of 16.1\% but cannibalizes the savings that are possible through optimization separately at each market. In future scenarios, the shares of savings from spot and reserve market could potentially reverse. CO 2 savings between 2.5\% and 9.2\% appear only through optimization at the spot market and could even turn negative if optimized solely at the reserve market.}, language = {en} }