  In this paper, we demonstrate that a consumer's marginal system impact is
only determined by their demand profile rather than their demand level. Demand
profile clustering is identical to cluster consumers according to their
marginal impacts on system costs. A profile-based uniform-rate price is
economically efficient as real-time pricing. We develop a criteria system to
evaluate the economic efficiency of an implemented retail price scheme in a
distribution system by comparing profile clustering and daily-average
clustering. Our criteria system can examine the extent of a retail price
scheme's inefficiency even without information about the distribution system's
daily cost structure. We analyze data from a real distribution system in China.
In this system, targeting each consumer's high-impact days is more efficient
than target high-impact consumers.
