| Popis: |
Deregulated electricity markets currently use an auction mechanism that minimizes the total offer cost to select offers and their power levels. Previous studies have shown that for a given set of offers, using an auction that minimizes the total payment cost would lead to a reduced cost that consumers have to pay, consistent with FERC's goals on standard market design. Building on our recent work on payment cost minimization for an energy market, in this paper, we study simultaneous auctions of both energy and spinning reserve markets. In this problem, whether a unit can be selected for spinning reserve is conditioned on its selection in the energy market; and for a generator, the sum of selected energy and reserve levels cannot exceed its capacity. The problem is solved by extending the augmented Lagrangian relaxation and surrogate optimization framework, where system demand on energy and reserve as well as unit capacity constraints are relaxed. In view of the dependency of reserve on energy, individual unit subproblems as opposed to individual energy or reserve offer subproblems are formed, and are solved by using dynamic programming (DP). Within DP, the energy and reserve levels for a particular "on" state are individually optimized in view that coupling constraints have been relaxed. The relaxation of capacity constraints also simplifies the previous procedure that compares "on state cost" vs. "off state cost" within DP. Numerical testing results demonstrate that the method is effective to provide near-optimal solutions, and provides valuable economic insights. |
