A METHOD TO SCHEDULE GENERATING-UNITS FOR COST-EFFECTIVE REDUCTION OF FOSSIL-FUEL EMISSIONS

Abstract

Scheduling methods, which reduce undesirable emissions from fossil-fuel generating units, has been a matter of considerable interest to power utilities. This paper introduces the idea that overall emission-reduction for a system can be achieved by optimizing the emissions at a few most emissive units, instead of doing so at all units. Such an approach becomes effective provided a sufficiently large cluster of the emissive units are subjected to the emission-optimization process. One important aspect of the problem that is addressed in the paper concerns the development of a suitable objective function which takes into account the cost-effectiveness of emission reduction. Both overall generation cost, as well as the emission at selected generating units, are taken relative to the respective base-case (non-optimal emission) values. The relative-cost and relative-emission terms are then included in a common 'penalty function', which is dimensionless. Minimization of this penalty function leads to an optimal operating point, at which a comparison of the reduction in overall relative-emission to the increase in relative-cost indicates the cost-effectiveness of the corresponding generation schedule. The approach is tested for an existing three-region scenario that forms part of the Indian power system. Results indicate the extent to which individual emissions can be reduced vis-a-vis the corresponding increase in overall cost of generation.