This document discusses the increasing integration of distributed energy resources (DER) like rooftop solar into electric grids. It notes that DER ownership is shifting to customers, and that DERs provide power back to the grid. The document outlines New York State's efforts through initiatives like Reforming the Energy Vision to encourage DER growth and integrate DERs into system planning and market operations. It emphasizes the need for new planning tools to account for DERs' variable nature, like backcasting to model solar output. The document concludes that fully integrating DERs will require improvements in grid visibility, coordination, and control as their penetration increases.