  The advent of intelligent agents who produce and consume energy by themselves
has led the smart grid into the era of "prosumer", offering the energy system
and customers a unique opportunity to revaluate/trade their spot energy via a
sharing initiative. To this end, designing an appropriate sharing mechanism is
an issue with crucial importance and has captured great attention. This paper
addresses the prosumers' demand response problem via energy sharing. Under a
general supply-demand function bidding scheme, a sharing market clearing
procedure considering network constraints is proposed, which gives rise to a
generalized Nash game. The existence and uniqueness of market equilibrium are
proved in non-congested cases. When congestion occurs, infinitely much
equilibrium may exist because the strategy spaces of prosumers are correlated.
A price-regulation procedure is introduced in the sharing mechanism, which
outcomes a unique equilibrium that is fair to all participants. Properties of
the improved sharing mechanism, including the individual rational behaviors of
prosumers and the components of sharing price, are revealed. When the number of
prosumers increases, the proposed sharing mechanism approaches social optimum.
Even with fixed number of resources, introducing competition can result in a
decreasing social cost. Illustrative examples validate the theoretical results
and provide more insights for the energy sharing research.
