Reliability/environmental impacts of wind energy curtailment due to ramping constraints

Wind is rapidly emerging as an important energy source in electric power systems. As wind penetration increases to relatively large scales, it becomes important in system planning to assess the capacity value and reliability impacts of wind resources, as well as the renewable energy utilization and the environmental benefits from them. Wind farms are at the top of the priority loading order, and all the wind energy generated is utilized to serve the load in scenarios where wind penetration is relatively low. In high wind penetration scenario, however, wind energy is occasionally spilled or curtailed due the limitations in operating reserve or ramping capability of the scheduled generating units. It becomes increasingly important to account for the wind curtailment scenarios and wind diversity effects when considering large scale wind power in capacity planning. Wind curtailment scenarios in different operating conditions have been analyzed in this paper by considering typical conventional generating units and their operating characteristics. Subsequently, an analytical technique for reliability and energy assessment is developed which incorporates the wind diversity and wind curtailment effects. The applications of the developed method to quantify the reliability, energy and environmental benefits of wind power are illustrated on a practical power system.