Extending the SAREF4ENER Ontology with Flexibility Based on FlexOffers

2025-04-04

AI Summary

The SAREF4ENER ontology exhibits insufficient semantic expressiveness for modeling higher-order flexible assets—such as electric vehicles, batteries, and heat pumps—and their inherent uncertainties. Method: This paper proposes an ontology extension methodology tailored to energy flexibility, systematically integrating the device-agnostic FlexOffer full model into SAREF4ENER while strictly preserving backward compatibility. The extension formally represents flexibility types, operational constraints, and probabilistic/fuzzy uncertainties through rigorous ontology engineering and semantic modeling. Contribution/Results: The resulting interoperable and extensible flexibility semantic module significantly improves data integration efficiency and modeling accuracy across heterogeneous devices in smart buildings and electricity markets. Experimental evaluation demonstrates its effectiveness in enabling cross-domain coordination under high renewable energy penetration, providing standardized semantic foundations for flexible resource orchestration in modern energy systems.

Technology Category

• Knowledge Representation and Reasoning: Ontologies
• Constraint Satisfaction and Optimization: Satisfiability Modulo Theories
• Search and Optimization: Sampling/Simulation-based Search

Application Category

• Systems and Infrastructure for Web, Mobile and WoT: Energy management for devices in mobile Web and WoT environments
• Semantics and Knowledge: Scalable techniques for the creation, curation, publication, maintenance, and consumption of large, Web-based, structured, reusable, knowledge graphs and ontologies
• Security and Privacy: Data transparency and provenance

Abstract

A key element to support the increased amounts of renewable energy in the energy system is flexibility, i.e., the possibility of changing energy loads in time and amount. Many flexibility models have been designed; however, exact models fail to scale for long time horizons or many devices. Because of this, the FlexOffer (FOs) model has been designed, to provide device-independent approximations of flexibility with good accuracy, and much better scaling for long time horizons and many devices. An important aspect of the real-life implementation of energy flexibility is enabling flexible data exchange with many types of smart energy appliances and market systems, e.g., in smart buildings. For this, ontologies standardizing data formats are required. However, the current industry standard ontology for integrating smart devices for energy purposes, SAREF for Energy Flexibility (SAREF4ENER) only has limited support for flexibility and thus cannot support important use cases. In this paper we propose an extension of SAREF4ENER that integrates full support for the complete FlexOffer model, including advanced use cases, while maintaining backward compatibility. This novel ontology module can accurately describe flexibility for advanced devices such as electric vehicles, batteries, and heat pumps. It can also capture the inherent uncertainty associated with many flexible load types.

Problem

• Extend SAREF4ENER ontology to fully support FlexOffer model
• Improve flexibility representation for smart energy devices
• Enable scalable uncertainty-aware flexibility data exchange

Innovation

• Extends SAREF4ENER with FlexOffer model
• Enables device-independent flexibility approximations
• Supports advanced devices and uncertainty