  The development of distributed generation technology is endowing consumers
the ability to produce energy and transforming them into "prosumers". This
transformation shall improve energy efficiency and pave the way to a low-carbon
future. However, it also exerts critical challenges on system operations, such
as the wasted backups for volatile renewable generation and the difficulty to
predict behavior of prosumers with conflicting interests and privacy concerns.
An emerging business model to tackle these challenges is peer-to-peer energy
sharing, whose concepts, structures, applications, models, and designs are
thoroughly reviewed in this paper, with an outlook of future research to better
realize its potentials.
