Driven by the "dual carbon" goals

traditional energy systems are evolving toward integrated energy systems (IES) characterized by multi-energy complementarity and deep coupling. The role of buildings is shifting from mere energy consumers to "prosumers" that integrate energy production

consumption

storage

and conversion. Building prosumers incorporate diverse distributed energy resources (DERs) such as rooftop photovoltaics (PV)

energy storage systems

electric vehicles (EVs)

and controllable loads

leading to increasingly complex interaction patterns with energy systems. However

the grid integration of massive prosumers poses formidable challenges to the IES. Effectively aggregating and regulating the flexibility of massive building prosumers is pivotal for ensuring the secure and economic operation of IES and enhancing system resilience. To this end

this paper presents a comprehensive and systematic review of the theories and technologies for building prosumers participating in IES load regulation. First

the integrated modeling approaches for building prosumers are systematically elaborated

with emphasis on their key physical characteristics

including building thermodynamic dynamics and the operational characteristics of equipment such as rooftop PV

energy storage

EVs and heat pumps. Second

the theories for evaluating the multi-dimensional flexibility potential of prosumers across electricity

heat and gas sectors are discussed in depth

focusing on feasible region characterization and uncertainty quantification methods. Subsequently

multi-level control strategies designed to achieve efficient prosumer synergy are reviewed in detail. Furthermore

through analyzing the cutting-edge demonstration projects at home and abroad

the current practical status of relevant technologies and explorations of business models are presented. Finally

the paper summarizes the key bottlenecks encountered at both the technical core level and the systemic institutional level

and concludes future research directions for building prosumers participating in urban IES load regulation.