Power-to-Heat solutions: The Danish district heating system

Bogdan Sipos; Niels Conradsen; George Xydis; Bogdan Sipos; Niels Conradsen; George Xydis

doi:10.3934/energy.2025060

AIMS Energy

2025, Volume 13, Issue 6: 1609-1628. doi: 10.3934/energy.2025060

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Research article

Power-to-Heat solutions: The Danish district heating system

1.
Department of Business Development and Technology, Aarhus University, Birk Centerpark 15, 7400 Herning, Denmark
2.
Vestas Wind Systems A/S, Hedeager 42, 8200 Aarhus N, Denmark
3.
Bridgestone, Bridgestone Europe NV/SA, Sigma 1, 8382 Hinnerup, Denmark
4.
Department of Mechanical Engineering, University of the Peloponnese, 1 Megalou Alexandrou str., Koukouli, 26334, Achaia, Greece

Received: 30 June 2025 Revised: 01 November 2025 Accepted: 02 December 2025 Published: 22 December 2025

The aim of this report is to investigate the potential of using surplus electricity generated by wind turbines in a power-to-heat (P2H) setup serving the Danish district heating market. The research establishes a theoretical position on variable renewable energy, district heating, heat pumps, boilers, and thermal energy storage through academic literature and industry professional reporting research. The empirical section touches upon the same topics, focusing on total energy production, curtailment, and district heating (DH) in Denmark. An analysis of the amount of curtailed power production in combination with electricity spot prices was used to calculate the corresponding heating demand that could be achieved if the power was used for large-scale heat pumps and electric boilers. It was found that the potential power-to-heat supply ranges from 18,100 to 63,380 households across the scenarios analyzed. The conclusion is that there seems to be a clear potential for redirecting the surplus electricity into DH to meet part of the Danish heat demand, and that the ongoing technological development of DH, thermal energy systems (TES), and variable renewable energy (VREs) in combination with market conditions favors a focus on sector coupling and P2H in the future.
- district heating,
- heat pumps,
- variable renewable energy,
- thermal energy
Citation: Bogdan Sipos, Niels Conradsen, George Xydis. Power-to-Heat solutions: The Danish district heating system[J]. AIMS Energy, 2025, 13(6): 1609-1628. doi: 10.3934/energy.2025060

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Abstract

The aim of this report is to investigate the potential of using surplus electricity generated by wind turbines in a power-to-heat (P2H) setup serving the Danish district heating market. The research establishes a theoretical position on variable renewable energy, district heating, heat pumps, boilers, and thermal energy storage through academic literature and industry professional reporting research. The empirical section touches upon the same topics, focusing on total energy production, curtailment, and district heating (DH) in Denmark. An analysis of the amount of curtailed power production in combination with electricity spot prices was used to calculate the corresponding heating demand that could be achieved if the power was used for large-scale heat pumps and electric boilers. It was found that the potential power-to-heat supply ranges from 18,100 to 63,380 households across the scenarios analyzed. The conclusion is that there seems to be a clear potential for redirecting the surplus electricity into DH to meet part of the Danish heat demand, and that the ongoing technological development of DH, thermal energy systems (TES), and variable renewable energy (VREs) in combination with market conditions favors a focus on sector coupling and P2H in the future.

References

[1]	Energistyrelsen (2023). Dansk klimapolitik. Available from: https://www.kefm.dk/Media/638315764817167867/Klimaprogram%202023.pdf.
[2]	Hansen KE, Xydis G (2023) Long-term heat storage opportunities of renewable energy for district heating networks. Proc Inst Civ Eng Energy, 1–22. https://doi.org/10.1680/jener.23.00023 doi: 10.1680/jener.23.00023
[3]	Xydis GA, Efthimiadou A, Ucal M (2022) Food to grid: Developing a Multi-Value renewable energy investment ecosystem. Energy Convers Manage 266: 115850. https://doi.org/10.1016/j.enconman.2022.115850 doi: 10.1016/j.enconman.2022.115850
[4]	Energy Supply (2021) De skal levere 50 MW varmepumpe og 60 MW fliskedel til Din Forsyning. Energy Supply. Available from: https://www.energy-supply.dk/article/view/773168/de_skal_levere_50_mw_varmepumpe_og_60_mw_fliskedel_til_din_forsyning.
[5]	Schweiger G, Rantzer J, Ericsson K, et al. (2017) The potential of power-to-heat in Swedish district heating systems. Energy 137: 661–669. https://doi.org/10.1016/j.energy.2017.02.075 doi: 10.1016/j.energy.2017.02.075
[6]	Böttger D, Götz M, Lehr N, et al. (2014) Potential of the power-to-heat technology in district heating grids in Germany. Energy Procedia 46: 246–253. https://doi.org/10.1016/j.egypro.2014.01.179 doi: 10.1016/j.egypro.2014.01.179
[7]	Park JH, Lim SY, Yoo SH (2019) Does combined heat and power mitigate CO₂ emissions? A cross-country analysis. Environ Sci Pollut Res 26: 11503–11507. https://doi.org/10.1007/s11356-019-04694-1 doi: 10.1007/s11356-019-04694-1
[8]	Dorotić H, Ban M, Pukšec T, et al. (2020) Impact of wind penetration in electricity markets on optimal power-to-heat capacities in a local district heating system. Renewable Sustainable Energy Rev 132: 110095. https://doi.org/10.1016/j.rser.2020.110095 doi: 10.1016/j.rser.2020.110095
[9]	Fambri G, Mazza A, Guelpa E, et al. (2023) Power-to-heat plants in district heating and electricity distribution systems: A techno-economic analysis. Energy Convers Manage 276: 116543. https://doi.org/10.1016/j.enconman.2022.116543 doi: 10.1016/j.enconman.2022.116543
[10]	Wang J, Cai H, You S, et al. (2020) A framework for techno-economic assessment of demand-side power-to-heat solutions in low-temperature district heating. Int J Electr Power Energy Syst, 122. https://doi.org/10.1016/j.ijepes.2020.106096 doi: 10.1016/j.ijepes.2020.106096
[11]	Arnaudo M, Giunta F, Dalgren J, et al. (2021) Heat recovery and power-to-heat in district heating networks—A techno-economic and environmental scenario analysis. Appl Therm Eng 185: 116388. https://doi.org/10.1016/j.applthermaleng.2020.116388 doi: 10.1016/j.applthermaleng.2020.116388
[12]	Lamaison N, Collette S, Vallée M, et al. (2019) Storage influence in a combined biomass and power-to-heat district heating production plant. Energy 186: 115714. https://doi.org/10.1016/j.energy.2019.07.044 doi: 10.1016/j.energy.2019.07.044
[13]	Li J, Lin J, Song Y, et al. (2018) Operation optimization of power to hydrogen and heat (P2HH) in ADN coordinated with the district heating network. IEEE Trans Sustainable Energy 10: 1672–1683. https://doi.org/10.1109/TSTE.2018.2868827 doi: 10.1109/TSTE.2018.2868827
[14]	Johannsen RM, Arberg E, Sorknæs P (2021) Incentivising flexible power-to-heat operation in district heating by redesigning electricity grid tariffs. Smart Energy 2: 100013. https://doi.org/10.1016/j.segy.2021.100013 doi: 10.1016/j.segy.2021.100013
[15]	Javanshir N, Syri S, Tervo S, et al. (2023) Operation of district heat network in electricity and balancing markets with the power-to-heat sector coupling. Energy 266: 126423. https://doi.org/10.1016/j.energy.2022.126423 doi: 10.1016/j.energy.2022.126423
[16]	Jimenez-Navarro JP, Kavvadias K, Filippidou F, et al. (2020) Coupling the heating and power sectors: The role of centralised combined heat and power plants and district heat in a European decarbonised power system. Appl Energy 270: 115134. https://doi.org/10.1016/j.apenergy.2020.115134 doi: 10.1016/j.apenergy.2020.115134
[17]	Rasmussen NB, Enevoldsen P, Xydis G (2020) Transformative multivalue business models: A bottom-up perspective on the hydrogen-based green transition for modern wind power cooperatives. Int J Energy Res 44: 3990–4007. https://doi.org/10.1002/er.5215 doi: 10.1002/er.5215
[18]	Estanqueiro A, Couto A (2021) New electricity markets—The challenges of variable renewable energy. Local Electricity Markets, 3–20. https://doi.org/10.1016/B978-0-12-820074-2.00016-2 doi: 10.1016/B978-0-12-820074-2.00016-2
[19]	Xydis G (2013) Wind energy to thermal and cold storage—A systems approach. Energy Build 56: 41–47. https://doi.org/10.1016/j.enbuild.2012.10.011 doi: 10.1016/j.enbuild.2012.10.011
[20]	Bird L, Cochran J, Wang X (2014) Wind and solar energy curtailment: Experience and practices in the United States. National Renewable Energy Laboratory. Available from: https://docs.nrel.gov/docs/fy14osti/60983.pdf.
[21]	Energistyrelsen (2022) Global Afrapportering 2022 (GA22): Eludveksling. Available from: https://www.kefm.dk/Media/637867480477626946/GA22%20-%20hovedrapport.pdf.
[22]	Armand M, Axmann P, Bresser D, et al. (2020) Lithium-ion batteries–Current state of the art and anticipated developments. J Power Sources 479: 228708. https://doi.org/10.1016/j.jpowsour.2020.228708 doi: 10.1016/j.jpowsour.2020.228708
[23]	Ebrahimi M (2019) Storing electricity as thermal energy at community level for demand side management. Energy 193: 116755. https://doi.org/10.1016/j.energy.2019.116755 doi: 10.1016/j.energy.2019.116755
[24]	Lund H, Werner S, Wiltshire R, et al. (2014) 4th Generation District Heating (4GDH): Integrating smart thermal grids into future sustainable energy systems. Energy 68: 1–11. https://doi.org/10.1016/j.energy.2014.02.089 doi: 10.1016/j.energy.2014.02.089
[25]	David A, Mathiesen BV, Averfalk H, et al. (2017) Heat roadmap Europe: large-scale electric heat pumps in district heating systems. Energies 10: 578. https://doi.org/10.3390/en10040578 doi: 10.3390/en10040578
[26]	Horten (2020) Ny projektbekendtgørelse for kollektive varmeforsyningsanlæg i høring. Available from: https://www.horten.dk/nyhedsliste/2020/oktober/ny-projektbekendtgoerelse-for-kollektive-varmeforsyningsanlaeg-i-hoering?fbclid = IwAR3sa_0hX-HHh9Y1pjCQqG2RmrJIp7YcPCpHzcFlsQMb8T9xvWXskk2kvkI.
[27]	Xydis G, Pechlivanoglou G, Nayeri NC (2015) Wind turbine waste heat recovery—A short-term heat loss forecasting approach. Challenges 6: 188–201. https://doi.org/10.3390/challe6020188 doi: 10.3390/challe6020188
[28]	Euroheat & Power (2022) Large heat pumps in district heating & cooling systems. Available from: https://www.euroheat.org/news/new-report-large-heat-pumps-in-district-heating-and-cooling-systems.
[29]	Nielsen MG, Morales JM, Zugno M, et al. (2016) Economic valuation of heat pumps and electric boilers in the Danish energy system. Appl Energy 167: 189–200. https://doi.org/10.1016/j.apenergy.2015.08.115 doi: 10.1016/j.apenergy.2015.08.115
[30]	Energistyrelsen (2013) Udredning vedrørende varmelagringsteknologier og store varmepumper til brug i fjernvarmesystemet. Available from: https://ens.dk/sites/ens.dk/files/Forskning_og_udvikling/udredning_om_varmelagringsteknologier_og_store_varmepumper_i_fjernvarmesystemet_nov_2013.pdf.
[31]	Strasszer D, Xydis G (2024) Integrating geothermal energy in Hungary: A case study on sustainable urban heating and emissions mitigation through the district heating infrastructure. Tunnelling Underground Space Technol 149: 105804. https://doi.org/10.1016/j.tust.2024.105804 doi: 10.1016/j.tust.2024.105804
[32]	Energinet (2022) Electricity Balance. Available from: https://www.energidataservice.dk/tso-electricity/ElectricityBalanceNonv.
[33]	Kortegaard Støchkel H, Lava Paaske B, Clausen KS (2017) Guidebook for large-scale heat pump projects in district heating (Danish: Drejebog til store varmepumpeprojekter i fjernvarmesystemet).
[34]	Statistics Denmark (2023) Prices of Electricity for non-households by annual consumption, price definition, and energy unit. Available from: https://m.statbank.dk/TableInfo/ENERGI2.
[35]	Svane K, Enevoldsen P, Xydis G (2023) Using existing cold stores as thermal energy storage. Environ Sci Pollut Res, 1–9. https://doi.org/10.1007/s11356-023-27752-1 doi: 10.1007/s11356-023-27752-1
[36]	Green Power Denmark (2019) Stoppede vindmøller er kommet for at blive. Available from: https://greenpowerdenmark.dk/nyheder/stoppede-vindmoeller-er-kommet-blive#:~:text=Omfanget%20af%20al%20s%C3%A5kaldt%20nedregulering,for%20nedregulering.
[37]	Nycander E, Lennart S, Olauson J, et al. (2020) Curtailment analysis for the nordic power system considering transmission capacity, inertia limits and generation flexibility. Renewable Energy 152: 942–960. https://doi.org/10.1016/j.renene.2020.01.059 doi: 10.1016/j.renene.2020.01.059
[38]	Danish Energy Agency (2022) Energy Statistics 2021. Copenhagen: Danish Energy Agency.
[39]	Danish Energy Agency (2017) Regulation and planning of district heating in Denmark.
[40]	Forsyningstilsynet (2022) Varmeprisen pr. 1. august 2022. Available from: https://forsyningstilsynet.dk/tal-fakta/priser/varmepriser/priser-pr-1-august-2022?fbclid=IwAR0sGRdVH7qN0pB5mPs48Uu6g7TK8ArbPqw868MBmkkmpxZzAe-6XS-ispU.
[41]	Wilczynski EJ, Chambers J, Patel MK, et al. (2023) Assessment of the thermal energy flexibility of residential buildings with heat pumps under various electric tariff designs. Energy Build 294: 113257. https://doi.org/10.1016/j.enbuild.2023.113257 doi: 10.1016/j.enbuild.2023.113257
[42]	Baral S, Xydis G (2025) Unleashing the economic potential of wind power for ancillary services. Int J Emerging Electr Power Syst 26: 155–182. https://doi.org/10.1515/ijeeps-2023-0267 doi: 10.1515/ijeeps-2023-0267
[43]	Marchi B, Nardin G, Barazzutti A, et al. (2025) Energy dialogue between district heating networks. J Cleaner Prod 522: 146378. https://doi.org/10.1016/j.jclepro.2025.146378 doi: 10.1016/j.jclepro.2025.146378
[44]	Bros-Williamson J (2025) Building energy demand pathways for reaching a net-zero carbon society. Cambridge Prisms: Energy Transitions 1: e3. https://doi.org/10.1017/etr.2025.10002 doi: 10.1017/etr.2025.10002
[45]	Adamo A, Martin H, Hoz JDL, et al. (2025) A review of worldwide strategies for promoting high-temperature heat pumps. Appl Sci 15: 839. https://doi.org/10.3390/app15020839 doi: 10.3390/app15020839

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