Bulk variable generation integration, conventional generation retirement and new generation and demand resources have raised new issues for power system planners. The need to understand the future need for flexibility from resources, as well as the development of the bulk transmission system to consider variable and uncertain flows is of critical importance to power system planning bodies. Variability and uncertainty of production and availability require new methods and practices to ensure system reliability is maintained into the future. A great deal of development has occurred in recent years to develop the means to plan systems successfully. As the implications of energy policy materialize, system planning has begun to adopt these methods to meet the new reality. This panel draws together experiences and insights from utilities, system operators and academia to present the current state of planning for flexibility.