IMPORTANT NOTE: This is the current version of NREL's Distribution System Unit cost Database and should be considered the most up-to-date. Compared to the previous version (https//data.nrel.gov/submissions/77) this database has additional data points and has been modified for improved usability. More information on the changes that have been made can be found in the attached file Unit_cost_database_guide_v2.docx. This guide also has important information about data sources and quality as well as intended use of the database. Please consult this database guide before using this data for any purpose. This database contains unit cost information for different components that may be used to integrate distributed photovotaic DPV systems onto distribution systems. Some of these upgrades and costs may also apply to integration of other distributed energy resources DER. Which components are required and how many of each is system-specific and should be determined by analyzing the effects of distributed PV at a given penetration level on the circuit of interest in combination with engineering assessments on the efficacy of different solutions to increase the ability of the circuit to host additional PV as desired. The current state of the distribution system should always be considered in these types of analysis. The data in this database was collected from a variety of utilities PV developers technology vendors and published research reports. Where possible we have included information on the source of each data point and relevant notes. In some cases where data provided is sensitive or proprietary we were not able to specify the source but provide other information that may be useful to the user e.g. year location where equipment was installed. NREL has carefully reviewed these sources prior to inclusion in this database. - Originated 01/02/2019 by National Renewable Energy Laboratory