  Energy storage has exhibited great potential in providing flexibility in
power system to meet critical peak demand and thus reduce the overall
generation cost, which in turn stabilizes the electricity prices. In this work,
we exploit the opportunities for the independent system operator (ISO) to
invest and manage storage as public asset, which could systematically provide
benefits to the public. Assuming a quadratic generation cost structure, we
apply parametric analysis to investigate the ISO's problem of economic
dispatch, given variant quantities of storage investment. This investment is
beneficial to users on expectation. However, it may not necessarily benefit
everyone. We adopt the notion of marginal system cost impact (MCI) to measure
each user's welfare and show its relationship with the conventional locational
marginal price. We find interesting convergent characteristics for MCI.
Furthermore, we perform $k$-means clustering to classify users for effective
user profiling and conduct numerical studies on both prototype and IEEE test
systems to verify our theoretical conclusions.
