Disclosed herein is a control system for NOx reduction in a power plant, the control system comprising a model predictive controller; a proportional integral differential controller and/or an adaptive controller; where the proportional integral differential controller and/or an adaptive controller are subordinated to and in operative communication with the model predictive controller; where the proportional integral differential controller and/or an adaptive controller comprise a feedback loop; a NOx reduction system comprising a NOx reducing agent supply tank and a water supply tank; and a furnace for combusting a fuel; where the furnace lies downstream of the NOx reduction system and where the furnace is provided with a plurality of nozzles that are in fluid communication with the NOx reduction system; where the control system is in electrical communication with the NOx reduction system.