Optimal energy purchases in deregulated California energy markets

In this paper, the problem of optimal energy purchases in a deregulated California energy market is studied. This commodity has been deregulated into three time sequential markets, known as the PX day-ahead, and hour-ahead (day of), and the ISO real-time energy markets. After deregulation, energy purchasers have to purchase energy on an hourly basis. The uncertain demands, the demand and supply bidding processes further complicate the decision process. It is challenging to explore an effective energy purchase strategy in the above energy markets with such a complex structure. By using a stochastic dynamic programming technique in this study, the problem is analytically resolved and an optimal solution is obtained with the forecasting supply curves. The cost functions of both the day-ahead and hour-ahead markets are proven to be convex with respect to the energy purchases in these two markets. With the optimal solution, we are able to demonstrate some interesting managerial implications which are not easy to obtain otherwise. A numerical example is also included to demonstrate the solution approach.