FUEL CONSTRAINED UNIT COMMITMENT

The paper presents a generalized method of solving the unit commitment problem with fuel constraints. In the presence of multiple fuels supplying a unit, the fuel price at a unit is not readily available. This fuel price could vary over different time intervals of the study period resulting in an increase in the complexity of the problem. The fuel constrained unit commitment problem is decomposed into a linear fuel dispatch (FD) problem and a unit commitment (UC) problem. The FD problem optimizes system fuel cost while satisfying fuel constraints and unit fuel requirements. It also calculates the effective price at a unit. The unit fuel prices are used in the UC problem (with no fuel constraints) to calculate the commitment of units and the resulting unit fuel demand. The solution process iterates between UC and FD until no further cost improvement is possible. Results of a utility system with gas constraints are presented to illustrate the highlights of the proposed method.