EnergyGuard aims to develop, kickstart and sustain an open, green and robust Testing Experimentation Facility operating under real-world conditions to empower innovators in bringing trustworthy AI products to the energy market in a cost-effective manner. It will integrate five significant European large-scale testing and experimentation facilities that cover the full energy value chain,supported by European’s greenest HPC infrastructure (Meluxina). This includes a digital twin (DT) of the Portuguese Transmission Network (RDN), the CEDER-CIEMAT Microgrid with its Distributed Energy Resources (DERs), the Hydrogen testing platforms at CEA LITEN, CARTIF, BER and CIEMAT, a high-fidelity local DT of Riga's multi-apartment residential buildings and the Antrodoco Renewable Energy Community. This includes a wide range of elements to cover diverse AI test needs,including wind power, photovoltaic systems, hydropower plant, AEM,PEM and SO eletrolysers, fuel cells, EV charging stations, electric and public buses and battery storage systems. The facilities will be accessible to EnergyGuard end-users through a set of properly configured Digital Twins (DTs) and curated assets, including data, models, inference APIs, services, and applications through a AI development Testing environment. It will enable easy seamless access to assets from the EU ecosystem including AIOD, Data Spaces, DIHs and other TEFs; Moreover, EnergyGuard facilitates users to validate their products with an Acceptance Environment and a common open AI risks database for a wide range of cybersecurity and trustworthy AI assessments. The TEF will serve as full infrastructure to support national AI regulatory sandbox initiatives and deliver 5 pilot cases for the private and public sector. EnergyGuard will build upon a long-term, self-sustainable business model driven by a new entity, incorporating market-ready features early in the design, such as a subscription/plan framework, billing, and professional support