New Approaches to Distributed PV Interconnection: Implementation Considerations for Addressing Emerging Issues

As the cost of installing distributed solar photovoltaics (PV) has fallen, the number of requests to interconnect PV systems to distribution grids has risen substantially in many utility service areas. In response, states and utilities are modifying their interconnection practices to address new DER challenges. This report examines emerging issues associated with interconnecting residential- and commercial-scale PV to facilitate sharing of lessons learned and best practices across jurisdictions. It covers issues related to allocating and understanding costs, understanding grid conditions to inform PV siting, interconnecting storage, automating processes, and requiring the availability of advanced inverter functions that can help increase PV hosting capacity. This report builds on an earlier study that reviews interconnection practices and costs across the western states (Bird et al. 2018). Both reports were developed as part of a larger, joint project between the Western Interstate Energy Board and the National Renewable Energy Laboratory, funded by the U.S. Department of Energy's Solar Energy Technologies Office, that examines barriers to distributed PV in the 11 states within the Western Interconnection.