Among the many challenges to transitioning to a climate-neutral society is the question of energy storage and balancing within smart energy systems, a topic thoroughly investigated in recent research by the team at Aalborg University in Northern Denmark [57.0°N, 9.9°E]. Their work reveals groundbreaking insights into how integrated energy systems can provide more cost-effective, flexible, and sustainable solutions.
The Holistic Approach: Smart Energy Systems
Central to the study is the “smart energy system” framework, which integrates electricity, heating, cooling, industry, transport, and material production. Unlike traditional energy systems that focus on a single sector (e.g., electricity), this approach evaluates how cross-sectoral synergies can unlock new efficiencies and reduce costs.
One key finding is the importance of sector coupling—the integration of various energy-consuming and -producing sectors. For instance, surplus renewable electricity can be channelled into heating or hydrogen production, stored more affordably, and later redeployed to meet demand spikes. This contrasts starkly with single-sector approaches that often face excessive curtailment (wasted energy) and higher balancing costs.
Five Levels of Integration: SESIL Framework
The study categorises integration into five levels of Smart Energy System Integration Levels (SESIL):
- Electricity-focused systems: Limited flexibility and high reliance on costly battery storage.
- Electricity plus heating and cooling: Introduces thermal storage, reducing overall costs and curtailment.
- Domestic energy systems: Adds transport and industry sectors, enabling innovations like vehicle-to-grid technology.
- Inclusion of international transport: Integrates aviation and shipping, focusing on power-to-X solutions for creating e-fuels.
- Full integration including material production: Fully realises the benefits of sector coupling, minimising curtailment and reducing costs through diversified storage.
The results highlight that as integration increases, energy systems become more economically efficient, with curtailment dropping from over 30% to just 3% in fully integrated setups.
Affordable Energy Storage: A Game-Changer
Energy storage is pivotal in this transition. The study identifies that more integrated systems enable the use of cost-effective storage methods, such as thermal and hydrogen storage, instead of expensive electricity-only solutions. Denmark, the focus of this case study, could repurpose its existing oil and gas storage facilities for green fuels, dramatically cutting the costs of new infrastructure.
Moreover, technologies like electrolysis for hydrogen production and large-scale thermal storage provide crucial flexibility, allowing systems to accommodate fluctuating renewable energy sources like wind and solar.
Implications for Policy and Practice
The findings are not just theoretical but have profound implications for global energy policy:
- Invest in sector coupling: Policymakers should prioritise frameworks that support cross-sectoral energy solutions.
- Expand storage infrastructure: Leveraging existing storage and focusing on multi-functional systems can cut costs.
- Optimise renewable deployment: Overbuilding renewables and integrating them with diverse storage options results in the most sustainable solutions.
A Sustainable Path Forward
This study affirms that achieving climate neutrality requires holistic, integrated approaches. It offers a clear roadmap to reduce costs, minimise waste, and create a resilient energy future aligned with the United Nations’ Sustainable Development Goal 7: affordable and clean energy for all. The message is clear: the best solutions emerge not from isolated efforts but from collaboration and integration across sectors.
Source
Energy balancing and storage in climate-neutral smart energy systems, Renewable and Sustainable Energy Reviews, 2025-03
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