High-resolution, spatial thermal energy demand analysis and workflow for a city district

Main Article Content

Hermann Edtmayer
Lisa-Marie Fochler
Thomas Mach
Jennifer Fauster
Eva Schwab
Christoph Hochenauer


Knowledge about the demand of renewable thermal energy is essential for the integrated planning of sustainable cities. Planners and decision-makers need high-quality and comprehensive data for rapid and decisive action. However, little to no corresponding information is available for the status quo or possible development scenarios. Thus, new methods for urban building energy modelling and simulation with high resolution and accuracy are needed. In this paper, we present the research we conducted on the thermal energy demand of a city district in Graz, Austria. We developed a novel bottom-up, white box, multi-tool workflow for performing large-scale and high-resolution modelling, simulation and analysis of urban buildings in different development scenarios. We calculated the demand for heating, cooling and hot water in full-year dynamic building simulations and assessed the results quantitatively and spatially. Our results in the Scenario 2050 show that despite massive densification of the building stock by 88%, the calculated heat energy demand rises only by 4%; while the cooling demand soars by 432%. All results are available as hourly mean values and annual totals and in easy-to-understand spatial map representations, thus supporting stakeholders to meet the net-zero CO2-equivalent emission targets of Graz.

Article Details

How to Cite
Edtmayer, H., Fochler, L.-M., Mach, T., Fauster, J., Schwab, E., & Hochenauer, C. (2023). High-resolution, spatial thermal energy demand analysis and workflow for a city district. International Journal of Sustainable Energy Planning and Management, 38, 47–64. https://doi.org/10.54337/ijsepm.7570


Østergaard PA, Johannsen RM, Duic N. Sustainable development using renewable energy systems. International Journal of Sustainable Energy Planning and Management 2020;29:1–6. https://doi.org/10.5278/ijsepm.4302.

Caragliu A, del Bo C, Nijkamp P. Smart cities in Europe. Journal of Urban Technology 2011;18:65–82. https://doi.org/10.1080/10630732.2011.601117.

Gholami M, Barbaresi A, Torreggiani D, Tassinari P. Upscaling of spatial energy planning, phases, methods, and techniques: A systematic review through meta-analysis. Renewable and Sustainable Energy Reviews 2020;132:110036. https://doi.org/10.1016/j.rser.2020.110036.

Giffinger R, Berger M, Weninger K, Zech S. Energieraumplanung - ein zentraler Faktor zum Gelingen der Energiewende 2021:1–148. https://doi.org/10.34726/808.

Sassen S. Who owns the city. Urban Age 2014. https://urbanage.lsecities.net/essays/who-owns-the-city-2014 (accessed May 19, 2021).

Sennett R. The stupefying smart city. Urban Age 2012. https://urbanage.lsecities.net/essays/the-stupefying-smart-city (accessed May 19, 2021).

Bauriedl S, Strüver A, editors. Smart City: kritische Perspektiven auf die Digitalisierung in Städten. Bielefeld: Transcript; 2018.

Stoeglehner G. Integrated spatial and energy planning: a means to reach sustainable development goals. Evolutionary and Institutional Economics Review 2020;17:473–86. https://doi.org/10.1007/S40844-020-00160-7.

Lund H, Werner S, Wiltshire R, Svendsen S, Thorsen JE, Hvelplund F, et al. 4th Generation District Heating (4GDH): Integrating smart thermal grids into future sustainable energy systems. Energy 2014;68:1–11. http://dx.doi.org/10.1016/j.energy.2014.02.089.

Müller A, Hummel M, Kranzl L, Fallahnejad M, Büchele R. Open source data for gross floor area and heat demand density on the hectare level for EU 28. Energies 2019;12. https://doi.org/10.3390/en12244789.

Csontos C, Soha T, Harmat Á, Campos J, Csüllög G, Munkácsy B. Spatial analysis of renewable-based hybrid district heating possibilities in a Hungarian rural area. International Journal of Sustainable Energy Planning and Management 2020;28:17–36. https://doi.org/10.5278/ijsepm.3661.

Pieper H, Lepiksaar K, Volkova A. GIS-based Approach to Identifying Potential Heat Sources for Heat Pumps and Chillers Providing District Heating and Cooling. International Journal of Sustainable Energy Planning and Management 2022;34:29–44. https://doi.org/10.54337/ijsepm.7021.

Quiquerez L, Faessler J, Lachal BM, Mermoud F, Hollmuller P. GIS methodology and case study regarding assessment of the solar potential at territorial level: PV or thermal? International Journal of Sustainable Energy Planning and Management 2015;6:3–16. https://doi.org/10.5278/ijsepm.2015.6.2.

Nageler PJ, Mach T, Heimrath R, Schardinger I, Langhammer F, Biberacher M, et al. Methoden- und Konzeptentwicklung zur Implementierung nachhaltiger Energiesysteme in Städten am Beispiel von Gleisdorf und Salzburg. Wien: Bundesministerium für Klimaschutz, Umwelt, Energie, Mobilität, Innovation und Technologie; 2021.

Mohajeri N, Perera ATD, Coccolo S, Mosca L, Le Guen M, Scartezzini JL. Integrating urban form and distributed energy systems: Assessment of sustainable development scenarios for a Swiss village to 2050. Renewable Energy 2019;143:810–26. https://doi.org/10.1016/j.renene.2019.05.033.

Muñoz I, Hernández P, Pérez-Iribarren E, Pedrero J, Arrizabalaga E, Hermoso N. Methodology for integrated modelling and impact assessment of city energy system scenarios. Energy Strategy Reviews 2020;32. https://doi.org/10.1016/J.ESR.2020.100553.

Alexander PJ, Fealy R, Mills GM. Simulating the impact of urban development pathways on the local climate: A scenario-based analysis in the greater Dublin region, Ireland. Landscape and Urban Planning 2016;152:72–89. https://doi.org/10.1016/j.landurbplan.2016.02.006.

Batas Bjelic IR, Rajakovic NLJ. National Energy and Climate Planning in Serbia: From Lagging Behind to an Ambitious EU Candidate? International Journal of Sustainable Energy Planning and Management 2021;32:47–60. https://doi.org/10.5278/ijsepm.6300.

Duygan M, Fischer M, Pärli R, Ingold K. Where do Smart Cities grow? The spatial and socio-economic configurations of smart city development. Sustainable Cities and Society 2022;77. https://doi.org/10.1016/j.scs.2021.103578.

Yigitcanlar T, Kamruzzaman M. Does smart city policy lead to sustainability of cities? Land Use Policy 2018;73:49–58. https://doi.org/10.1016/J.LANDUSEPOL.2018.01.034.

Maier S. Smart energy systems for smart city districts: case study Reininghaus District. Energy, Sustainability and Society 2016;6. https://doi.org/10.1186/s13705-016-0085-9.

Stanzel L, Scholz J, Mauthner F. A Spatial Data Analysis Approach for Public Policy Simulation in Thermal Energy Transition Scenarios. Data Science – Analytics and Applications 2019:63–8. https://doi.org/10.1007/978-3-658-27495-5_8.

Stoeglehner G, Abart-Heriszt L. Integrated spatial and energy planning in Styria – A role model for local and regional energy transition and climate protection policies. Renewable and Sustainable Energy Reviews 2022;165:112587. https://doi.org/10.1016/j.rser.2022.112587.

Mutani G, Todeschi V. GIS-based urban energy modelling and energy efficiency scenarios using the energy performance certificate database. Energy Efficiency 2021 14:5 2021;14:1–28. https://doi.org/10.1007/S12053-021-09962-Z.

Heidenthaler D, Leeb M, Reindl P, Kranzl L, Bednar T, Moltinger M. Building stock characteristics of residential buildings in Salzburg, Austria based on a structured analysis of energy performance certificates. Energy and Buildings 2022;273:112401. https://doi.org/10.1016/J.ENBUILD.2022.112401.

Prina MG, Manzolini G, Moser D, Nastasi B, Sparber W. Classification and challenges of bottom-up energy system models - A review. Renewable and Sustainable Energy Reviews 2020;129. https://doi.org/10.1016/j.rser.2020.109917.

Langevin J, Reyna JL, Ebrahimigharehbaghi S, Sandberg N, Fennell P, Nägeli C, et al. Developing a common approach for classifying building stock energy models. Renewable and Sustainable Energy Reviews 2020;133:110276. https://doi.org/10.1016/j.rser.2020.110276.

Oraiopoulos A, Howard B. On the accuracy of Urban Building Energy Modelling. Renewable and Sustainable Energy Reviews 2022;158:111976. https://doi.org/10.1016/j.rser.2021.111976.

Todeschi V, Boghetti R, Kämpf JH, Mutani G. Evaluation of urban-scale building energy-use models and tools—application for the city of Fribourg, Switzerland. Sustainability (Switzerland) 2021;13:1–22. https://doi.org/10.3390/su13041595.

Neumann HM, Hainoun A, Stollnberger R, Etminan G, Schaffler V. Analysis and evaluation of the feasibility of positive energy districts in selected urban typologies in Vienna using a bottom-up district energy modelling approach. Energies 2021;14. https://doi.org/10.3390/EN14154449.

Geppert LN, Ickstadt K, Karl F, Münch J, Steinbrecher M. Visualising Complex Data Within a Data Science Loop: A Spatio-Temporal Example from Football. Artificial Intelligence, Big Data and Data Science in Statistics: Challenges and Solutions in Environmetrics, the Natural Sciences and Technology 2022:301–19.

Meredith D. Explaining Research: How to Reach Key Audiences to Advance Your Network. Oxford University Press; 2021. https://doi.org/10.1093/oso/9780197571316.001.0001.

Rosling H. The best Hans Rosling talks you’ve ever seen | TED Talks. TED Ideas Worth Spreading n.d. https://www.ted.com/playlists/474/the_best_hans_rosling_talks_yo (accessed November 18, 2022).

Stadtbaudirektion Graz. Smart City Graz n.d. http://www.smartcitygraz.at/ (accessed March 1, 2023).

EQUA Simulation AB. IDA Indoor Climate and Energy. IDA ICE - Simulation Software | EQUA n.d. https://www.equa.se/en/ida-ice (accessed November 18, 2022).

Nageler P, Heimrath R, Mach T, Hochenauer C. Prototype of a simulation framework for georeferenced large-scale dynamic simulations of district energy systems. Applied Energy 2019;252:113469. https://doi.org/10.1016/j.apenergy.2019.113469.

Nageler P, Schweiger G, Schranzhofer H, Mach T, Heimrath R, Hochenauer C. Novel method to simulate large-scale thermal city models. Energy 2018;157:633–46. https://doi.org/10.1016/j.energy.2018.05.190.

Nageler P, Zahrer G, Heimrath R, Mach T, Mauthner F, Leusbrock I, et al. Novel validated method for GIS based automated dynamic urban building energy simulations. Energy 2017;139:142–54. https://doi.org/10.1016/j.energy.2017.07.151.

PostgreSQL Global Development. PostgreSQL: The World’s Most Advanced Open Source Relational Database. PostgreSQL 2022. https://www.postgresql.org/ (accessed November 18, 2022).

Statistik Austria. Address, Buildings and Dwellings Register. Infromation about the Address, Buildings and Dwellings Register n.d. https://www.statistik.at/en/databases/address-buildings-and-dwellings-register/address-buildings-and-dwellings-register/information (accessed November 18, 2022).

Wohnbau V-LS A15EW Energie und. Abteilung 15 - FA Energie und Wohnbau. Verwaltung - Land Steiermark n.d. https://www.verwaltung.steiermark.at/cms/ziel/74836184/DE/ (accessed February 1, 2023).

Vectorworks Inc. 3D Design Software - Fully Integrated BIM | Vectorworks. One Flexible Solution for Your Entire Design Process n.d. https://www.vectorworks.net/en-GB (accessed November 18, 2022).

Daga L. A Practical Approach to Level of Detail (LOD) - United-BIM 2021. https://www.united-bim.com/practical-approach-to-level-of-detail/ (accessed November 18, 2022).

Casini M. Chapter 4 - Building information modeling. In: Casini M, editor. Construction 4.0, Woodhead Publishing; 2022, p. 189–219. https://doi.org/10.1016/B978-0-12-821797-9.00002-7.

Nageler P, Mach T, Heimrath R, Schranzhofer H, Hochenauer C. Generation Tool for Automated Thermal City Modelling. Applied Mechanics and Materials 2019;887:292–9. https://doi.org/10.4028/www.scientific.net/amm.887.292.

The QGIS project. QGIS A Free and Open Source Geographic Information System. Welcome to the QGIS Project! n.d. https://qgis.org/en/site/ (accessed November 18, 2022).

Austrian Central Institute for Meteorology and Geodynamics ZAMG. TAWES-Verlaufsgraphiken Graz Universität n.d. https://www.zamg.ac.at/cms/de/wetter/wetterwerte-analysen/tawes-verlaufsgraphiken/graz_universitaet/temperatur/?mode=geo&druckang=red (accessed February 28, 2022).

Österreichisches Institut für Bautechnik. OIB-Richtlinie 6 - Leitfaden OIB-RL 6 Energietechnisches Verhalten von Gebäuden OIB-330.6-028/19. Vienna, Austria: Österreichisches Institut für Bautechnik; 2019.

Loga T, Stein B, Diefenbach N. TABULA building typologies in 20 European countries—Making energy-related features of residential building stocks comparable. Energy and Buildings 2016;132:4–12. https://doi.org/10.1016/J.ENBUILD.2016.06.094.

TABULA Project Team. TABULA webtool 2017:date accessed 2021/10. https://webtool.building-typology.eu/#bm.

EQUA Simulation AB. IDA Indoor Climate and Energy User Manual Version 4.8. 2018.

SIA 2024:2015. Raumnutzungsdaten für die Energie- und Gebäudetechnik. Zürich, Schweiz: Schweizerischer Ingenieur- und Architektenverein; 2015.

IPCC 2014. Climate Change 2014: Synthesis Report. Contribution of Working Groups I, II and III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Geneva, Switzerland: 2014.

Chimani B, Heinrich G, Hofstätter M, Kerschbaumer M, Kienberger S, Leuprecht A, et al. Klimaszenarien für das Bundesland Steiermark bis 20100. Graz, Austria: Land Steiermark, Fachabteilung Energie und Wohnbau; 2016.

Meteotest AG. Meteonorm Software - Worldwide irradiation data n.d. https://meteonorm.com/en/, date accsessd: 2021/06.

Nageler P, Schweiger G, Schranzhofer H, Heimrath R, Mach T, Fochler LM, et al. Co-simulation Workflow for the Dynamic Modelling and Simulation of Large-scale District Energy Systems. Proceedings of the 16th IBPSA Conference, Rome, Italy: IBPSA International Building Performance Simulation Association; 2019. https://doi.org/ISBN: 978-1-7750520-1-2.

Nageler PJ, Mach T, Heimrath R, Schardinger I, Langhammer F, Biberacher M. ECC - EnergyCityConcepts Ein Projektbericht im Rahmen des Programms. 2018.

Edtmayer H, Nageler P, Heimrath R, Mach T, Hochenauer C. Investigation on sector coupling potentials of a 5th generation district heating and cooling network. Energy 2021;230:120836. https://doi.org/10.1016/j.energy.2021.120836.

IPCC. AR6 Synthesis Report: Climate Change 2022 — IPCC n.d. https://www.ipcc.ch/report/sixth-assessment-report-cycle/ (accessed November 21, 2022).

Anderl M, et al. Klimaschutzbericht 2022. Wien: Umweltbundesamt; 2022.

Bundesregierung Deutschland. Klimaschutzbericht 2022. Die Bundesregierung informiert | Startseite n.d. https://www.bundesregierung.de/breg-de/themen/klimaschutz/klimaschutzbericht-2022-2130484 (accessed November 21, 2022).

Nageler P, Schweiger G, Pichler M, Brandl D, Mach T, Heimrath R, et al. Validation of dynamic building energy simulation tools based on a real test-box with thermally activated building systems (TABS). Energy and Buildings 2018;168:42–55. https://doi.org/10.1016/J.ENBUILD.2018.03.025.

Schweiger G, Heimrath R, Falay B, O’Donovan K, Nageler P, Pertschy R, et al. District energy systems: Modelling paradigms and general-purpose tools. Energy 2018;164:1326–40. https://doi.org/10.1016/j.energy.2018.08.193.

Nageler P, Koch A, Mauthner F, Leusbrock I, Mach T, Hochenauer C, et al. Comparison of dynamic urban building energy models (UBEM): Sigmoid energy signature and physical modelling approach. Energy and Buildings 2018;179:333–43. https://doi.org/10.1016/j.enbuild.2018.09.034.

Schweiger G, Heimrath R, Nageler P, O’Donovan K, Salzmann M, Schrammel H, et al. Tools and methods for modelling district heating systems : A comprehensive comparison. 3rd International Conference on Smart Energy Systems and 4th Generation District Heating 2017:1–34.

VR4UrbanDev - Virtual Reality as an innovative, digital tool for the integrative urban development of the future n.d. https://nachhaltigwirtschaften.at/en/sdz/projects/virtual-reality-as-an-innovative-digital-tool-for-the-integrative-urban-development-of-the-future.php (accessed February 1, 2023).

Lazar R, Sulzer W. Stadtklimaanalysen. Stadt Graz; Stadtplanung, Stadtvermessung; 2020.

ZAMG. ZAMG Zentralanstalt für Meteorologie und Geodynamik. Stadtklima Zukunft. ZAMG 2021. https://www.zamg.ac.at/cms/de/klima/informationsportal-klimawandel/daten-download/stadtklima-zukunft (accessed May 23, 2021).

Stadt Graz. Stadtistik Graz. 1.Auflage. Graz: Stadt Graz Präsidialabteilung - Statistik; 2019.

Mair am Tinkhof O, Schuster M, Riedmann A, Thenius G, Trebut F. Siedlungen und Quartiere Klimaneutral mit dem klimaaktiv Standard. Wien: Bundesministerium für Klimaschutz, Umwelt, Energie, Mobilität, Innovation und Technologie; 2022.

Austrian Energy Agency. Der klimaaktiv Kriterienkatalog 2020, klimaaktiv n.d. https://www.klimaaktiv.at/bauen-sanieren/gebaeudedeklaration/kriterienkatalog-2020.html (accessed November 18, 2022).