  This paper proposes an energy management technique for a consumer-to-grid
system in smart grid. The benefit to consumers is made the primary concern to
encourage consumers to participate voluntarily in energy trading with the
central power station (CPS) in situations of energy deficiency. A novel system
model motivating energy trading under the goal of social optimality is
proposed. A single-leader multiple-follower Stackelberg game is then studied to
model the interactions between the CPS and a number of energy consumers (ECs),
and to find optimal distributed solutions for the optimization problem based on
the system model. The CPS is considered as a leader seeking to minimize its
total cost of buying energy from the ECs, and the ECs are the followers who
decide on how much energy they will sell to the CPS for maximizing their
utilities. It is shown that the game, which can be implemented distributedly,
possesses a socially optimal solution, in which the benefits-sum to all
consumers is maximized, as the total cost to the CPS is minimized. Numerical
analysis confirms the effectiveness of the game.
