Lawrence Berkeley National Laboratory

Buildings are becoming ever more complex to manage during operations, driven by increasing dynamics in energy demand, intermittent on-site power generation, and distributed energy resources, compounded by variable grid pricing signals and the rising threat of extreme weather events causing large-scale power outages. To achieve optimal performance in energy efficiency, demand flexibility, energy resilience, and occupant comfort, new methods and tools are essential for transforming design and operations across a building’s entire life cycle. Digital Twins (DTs), enabled by recent advances in ubiquitous sensing, big data, cloud computing, and AI, offer a transformative approach to creating a real-time, bi-directional digital counterpart of a physical building. This paper presents ten critical questions highlighting the most foundational issues underpinning the successful deployment of digital twins for buildings. The questions are holistically structured around three core themes to provoke significant research and accelerate adoption. The paper first examines the Users and Business aspects, including use cases, stakeholder alignment, business models, and governance structures. It then dives into the Technology foundation, addressing key components, layered software architectures, data integration, semantic interoperability, and the critical issues of cybersecurity and privacy. Finally, it explores Application aspects, such as the role of AI, performance metrics and standards, and the current landscape of software tools. DT technology is still in the early stages of adoption in buildings despite successful pilot applications in preventive maintenance, FDD, and advanced controls to optimize building performance. Several barriers need to be addressed to scale up DT technology in buildings, including high development and maintenance costs, the lack of data-rich infrastructure in buildings, and a shortage of skilled workforce.