Over the past three years, PJM and stakeholders have worked to define business rules for hybrid resources participating in PJM’s markets. The first phase of this work focused on solar-storage hybrids. The second phase expanded the hybrids participation model to all types of inverter-based hybrid resources. The third phase of this work will focus on enhancements and/or clarifications to the existing market rules for these resources, as well as the definition of additional market rules for non-inverter based hybrid configurations (e.g., gas plus storage).