When a power and utility operation within an industrial plant runs multiple steam producing units, turbines, compressors and/or chillers, the goal is to allocate load across these units in the most economical way. This is made difficult by the fact that load demands are continually changing and the reality that it is difficult to calculate each unit’s efficiency in real-time and make minute by minute load allocation adjustments. For human operating personnel, it is not typically possible to have load distributed in the most cost effective manner at all times. For this reason, it is typical that a site will simply base load some units and follow load swings with others. This normally does not result in best cost operation.
If demand is allocated on a cost basis across available utility producing units at all times significant savings result. Emerson assists industrial utility owners with cost based load allocation (economic dispatch) by implementing control solutions that calculate unit costs in real-time and automatically allocate load within defined constraints. This results in savings because operating cost is calculated on an overall basis. Emerson’s SmartProcess® solutions consider the efficiency of the producing group and can use all (or an operations defined number) of them to respond to demand changes. At the same time, operating constraints such as turn-down, ramp rate, and emissions are all taken into account. This results in best cost load allocation at all times.