Lawrence Berkeley National Laboratory

Field studies show that demand flexibility in residential buildings can save up to 20% in energy costs, but requires secure, automated, and reliable coordination across multiple devices and stakeholders. Integration between platforms is typically done on a one-to-one basis, requiring device-specific and platform-specific programming and updates. This manual process is expensive, as developers must manage protocol translation and data exchange through proprietary or reverse-engineered APIs, often without a consistent or standardized data format. This fragmented approach hinders scalability and slows the adoption of demand flexibility technologies. Recently, several communication protocols have emerged in the US to address these challenges by defining common data models and standard interfaces for device-to-grid and device-to-device interactions. Although many of these protocols intend to provide comprehensive interoperability, in practice, each addresses a specific segment of the ecosystem and serves a distinct set of stakeholders. Understanding their respective roles and limitations is essential for deploying flexible, interoperable energy systems at scale. In this paper, we define a set of desirable features for achieving interoperability in residential demand flexibility and use them to evaluate emerging communication protocols, such as Open Automated Demand Response (OpenADR) 3, Institute of Electrical and Electronics Engineers (IEEE) 2030.5, Matter, Consumer Technology Association (CTA)-2045, Open Charge Point Protocol (OCPP) and Home Connectivity Alliance (HCA), and their underlying data models. We analyze their use cases, stakeholders and their areas of overlap. Finally, we outline our vision on how these protocols can work together to enable seamless utility-to-device communication, supporting scalable, interoperable demand flexibility and informing researchers, policymakers, and industry stakeholders.