  We study the role of a market maker (or market operator) in a transmission
constrained electricity market. We model the market as a one-shot networked
Cournot competition where generators supply quantity bids and load serving
entities provide downward sloping inverse demand functions. This mimics the
operation of a spot market in a deregulated market structure. In this paper, we
focus on possible mechanisms employed by the market maker to balance demand and
supply. In particular, we consider three candidate objective functions that the
market maker optimizes - social welfare, residual social welfare, and consumer
surplus. We characterize the existence of Generalized Nash Equilibrium (GNE) in
this setting and demonstrate that market outcomes at equilibrium can be very
different under the candidate objective functions.
