Synergies and trade-offs between storage, transmission, and sector coupling in high renewable energy systems

Sumanth Yamujala; Matti Koivisto; Magnus Korpås; Madeleine McPherson; Niina Helistö; Debra Lew; Diego Tejada-Arango; Germán Morales-España; Damian Flynn; Bethany Frew; Thomas Heggarty; Juha Kiviluoma; Hannele Holttinen

doi:10.1016/j.energy.2025.137701

Synergies and trade-offs between storage, transmission, and sector coupling in high renewable energy systems

Sumanth Yamujala^*
, Matti Koivisto
, Magnus Korpås
, Madeleine McPherson
, Niina Helistö
, Debra Lew
, Diego Tejada-Arango
, Germán Morales-España
, Damian Flynn
, Bethany Frew
, Thomas Heggarty
, Juha Kiviluoma
, Hannele Holttinen

^*Corresponding author for this work

Technical University of Denmark (DTU)
Norwegian University of Science and Technology (NTNU)
University of Victoria (BC)
Energy Systems Integration Group (ESIG)
Netherlands Organisation for Applied Scientific Research (TNO)
Comillas Pontifical University
Delft University of Technology
University College Dublin
National Renewable Energy Laboratory (NREL)
Réseau de Transport d'Électricité (RTE)
Aalto University

Research output: Contribution to journal › Article › Scientific › peer-review

5 Citations (Scopus)

Abstract

Energy storage, transmission, and sector coupling are some prominent flexibility solutions to support variable renewable energy (VRE) integration. However, investment cost uncertainties and public acceptance could hamper the deployment of these flexibility solutions. This raises questions about the development and cost-effectiveness of future energy systems, especially on how the dependence on local and cross-border solutions of flexibility would evolve if the uptake of these solutions is restricted. In this context, this paper identifies the synergies among flexibility options under restrictions on transmission expansion or increased costs of energy storage. It contributes to determining whether investments in energy storage and/or transmission expansion offer the least-cost transition and investigates the impact of sector coupling on these solutions. A long-term energy system planning and optimisation model towards 2050 is developed using the open-source energy system optimisation tool Balmorel, and a case study of the countries surrounding the Baltic Sea and the North Sea is established. Five cases with restrictions imposed on transmission expansion and higher energy storage technology costs are analysed at different levels of sector coupling. The results highlight the importance of transmission expansion at all levels of sector coupling. As the level of sector coupling increases, uncertainties around the cost of energy storage drive the least-cost pathways. Optimal investment solutions are found to have a mix of transmission and energy storage in capacity expansion at all levels of sector coupling.

Original language	English
Article number	137701
Journal	Energy
Volume	334
DOIs	https://doi.org/10.1016/j.energy.2025.137701
Publication status	Published - 15 Oct 2025
MoE publication type	A1 Journal article-refereed

Funding

This work is part of an international research collaboration under IEA Wind TCP Task 25 “Design and operation of energy systems with large amounts of variable generation”. The authors acknowledge support from the Danish Energy Technology Development and Demonstration Programme (EUDP) IEA WIND Task 25 (Danish Energy Agency, Denmark, grant 64021-0013). This work was authored in part by the National Renewable Energy Laboratory for the U.S. Department of Energy (DOE) under Contract No. DE-AC36-08GO28308. Funding provided by the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, Wind Energy Technologies Office . The views expressed in the article do not necessarily represent the views of the DOE or the U.S. Government. The U.S. Government retains and the publisher, by accepting the article for publication, acknowledges that the U.S. Government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this work, or allow others to do so, for U.S. Government purposes. This work was authored in part by the National Renewable Energy Laboratory for the U.S. Department of Energy (DOE) under Contract No. DE-AC36-08GO28308. Funding provided by the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, Wind Energy Technologies Office . The views expressed in the article do not necessarily represent the views of the DOE or the U.S. Government. The U.S. Government retains and the publisher, by accepting the article for publication, acknowledges that the U.S. Government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this work, or allow others to do so, for U.S. Government purposes. This work is part of an international research collaboration under IEA Wind TCP Task 25 “Design and operation of energy systems with large amounts of variable generation”. The authors acknowledge support from the Danish Energy Technology Development and Demonstration Programme (EUDP) IEA WIND Task 25 ( Danish Energy Agency, Denmark , grant 64021-0013 ).

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

SDG 7 Affordable and Clean Energy

Keywords

Energy storage
Flexibility
Generation expansion
Integrated energy systems
Sector coupling
Transmission planning

Access to Document

10.1016/j.energy.2025.137701

Cite this

Yamujala, S., Koivisto, M., Korpås, M., McPherson, M., Helistö, N., Lew, D., Tejada-Arango, D., Morales-España, G., Flynn, D., Frew, B., Heggarty, T., Kiviluoma, J., & Holttinen, H. (2025). Synergies and trade-offs between storage, transmission, and sector coupling in high renewable energy systems. Energy, 334, Article 137701. https://doi.org/10.1016/j.energy.2025.137701

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abstract = "Energy storage, transmission, and sector coupling are some prominent flexibility solutions to support variable renewable energy (VRE) integration. However, investment cost uncertainties and public acceptance could hamper the deployment of these flexibility solutions. This raises questions about the development and cost-effectiveness of future energy systems, especially on how the dependence on local and cross-border solutions of flexibility would evolve if the uptake of these solutions is restricted. In this context, this paper identifies the synergies among flexibility options under restrictions on transmission expansion or increased costs of energy storage. It contributes to determining whether investments in energy storage and/or transmission expansion offer the least-cost transition and investigates the impact of sector coupling on these solutions. A long-term energy system planning and optimisation model towards 2050 is developed using the open-source energy system optimisation tool Balmorel, and a case study of the countries surrounding the Baltic Sea and the North Sea is established. Five cases with restrictions imposed on transmission expansion and higher energy storage technology costs are analysed at different levels of sector coupling. The results highlight the importance of transmission expansion at all levels of sector coupling. As the level of sector coupling increases, uncertainties around the cost of energy storage drive the least-cost pathways. Optimal investment solutions are found to have a mix of transmission and energy storage in capacity expansion at all levels of sector coupling.",

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AU - McPherson, Madeleine

AU - Helistö, Niina

AU - Lew, Debra

AU - Tejada-Arango, Diego

AU - Morales-España, Germán

AU - Flynn, Damian

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AB - Energy storage, transmission, and sector coupling are some prominent flexibility solutions to support variable renewable energy (VRE) integration. However, investment cost uncertainties and public acceptance could hamper the deployment of these flexibility solutions. This raises questions about the development and cost-effectiveness of future energy systems, especially on how the dependence on local and cross-border solutions of flexibility would evolve if the uptake of these solutions is restricted. In this context, this paper identifies the synergies among flexibility options under restrictions on transmission expansion or increased costs of energy storage. It contributes to determining whether investments in energy storage and/or transmission expansion offer the least-cost transition and investigates the impact of sector coupling on these solutions. A long-term energy system planning and optimisation model towards 2050 is developed using the open-source energy system optimisation tool Balmorel, and a case study of the countries surrounding the Baltic Sea and the North Sea is established. Five cases with restrictions imposed on transmission expansion and higher energy storage technology costs are analysed at different levels of sector coupling. The results highlight the importance of transmission expansion at all levels of sector coupling. As the level of sector coupling increases, uncertainties around the cost of energy storage drive the least-cost pathways. Optimal investment solutions are found to have a mix of transmission and energy storage in capacity expansion at all levels of sector coupling.

KW - Energy storage

KW - Flexibility

KW - Generation expansion

KW - Integrated energy systems

KW - Sector coupling

KW - Transmission planning

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Synergies and trade-offs between storage, transmission, and sector coupling in high renewable energy systems

Abstract

Funding

UN SDGs

Keywords

Access to Document

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Cite this