A method to schedule generating units for cost‐effective reduction of fossil‐fuel emissions

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.