Using of a cost - based Unit Commitment algorithm to assist bidding strategy decisions

the proposed method, the profit maximization problem is transformed into a minimization problem that can be solved by a traditional hydro-thermal unit commitment program after implementing a few modifications. The paper describes t he modifications introduced in a unit commitment program based on the Lagrangian relaxation approach and on a disaggregated Bundle method for the solution of the dual problem. It also presents some results obtained for a realistic data set of hydro-thermal power plants. The results are discussed in order to emphasize how the method can be applied to assess the bidding strategy choice of a given company. set of indexes of available thermal units in the system and those belonging to the company, respectively (I : number of thermal units; i: thermal unit index). H, H' set of indexes of available hydro units in the system and those belonging to the company, respectively (H : number of hydro units; h: hydro unit index). T set of time periods in the optimization horizon (T : number of time periods ; t: time period index). D T-dimensional vector of load demands D t in each period t. u I-rows T-columns matrix, whose rows are the T-dimensional arrays u i of the 0-1 variables u i,t indicating the commitment state of thermal unit i during period t. p I I-rows T-columns matrix, whose rows are the T-dimensional arrays p i of production levels p i,t of thermal unit i during each period t. p H H-rows T-columns matrix, whose rows are the T-dimensional arrays p h of production levels p h,t of hydro unit h during each period t. iih ppp minimum/maximum outputs of the units. , ud ii ττ minimum up-and down-times of thermal units. , it c per hour operating cost of committed thermal unit i at period t, as a quadratic function of production level p i,t. , u it s start-up cost which is charged whenever thermal unit i is committed at the beginning of period t. It can depend on the number of periods that the unit has been down. a water discharge rate and spillage of hydro unit h and net inflow rate of its reservoir during period t, respectively. n t length of period t. Summation t tT n ∈ ∑ is equal to the optimization horizon. , ht V storage volume of the reservoir of hydro unit h at the end of period …