Determining optimal fuel mix for environmental dispatch

This paper develops a method for obtaining the optimal mix of high and low sulfur fuels for users such as electric utilities and large industrial complexes. The mix is determined so that environmental limits are met and plant operating schedules are fully maintained. The problem is formulated in a "minimum energy with penalty function" format and well known optimal control theory methods are applied to obtain the solution. An adaption of this or similar procedures may be necessary in the future because of the scarcity of low sulfur fuels and under appropriate meteorological conditions a fuel cost savings of approximately $20 000 per day for 1000 MWe coal-fired generation plant may be obtained. The methods developed here may be used with present electric utility economic dispatch programs to integrate local meteorology and environmental limits with plant economics. An example application demonstrates the methods.