DigiRES: Digital Integration of Multi-Energy Flexibility Assets in Regional Energy Systems

The ongoing energy transition, driven by the proliferation of distributed renewable energy sources (DRES), necessitates advanced coordination of flexible resources across multiple energy carriers. This paper investigates recent developments and challenges in enabling multi-energy flexibility within regional energy systems, emphasizing the integration of electricity, heating, cooling, and transportation vectors. We analyze the emerging paradigm of Flexibility-as-a-Service (FaaS), which aims to unlock and aggregate flexibility from distributed assets via innovative business models and intelligent digital platforms. Building on this foundation, we introduce a conceptual framework developed in the DigiRES project, which leverages semi/self-learning AI models, an Internet-of-Energy (IoE) platform, and structured market layers to optimize flexibility allocation in a secure and privacy-preserving manner. Through a comprehensive review of enabling technologies, regulatory and market barriers, and validation across demonstration sites in the Netherlands, Sweden, and Belgium, this paper highlights the key opportunities and practical constraints for realizing scalable, interoperable, and regionally adaptable multi-energy flexibility markets.