The California Energy Commission is cost-sharing research with the Department of Energy through the National Renewable Energy Laboratory to address distributed energy resources (DER) topics. These efforts include developing interconnection and power management technologies, modeling the impacts of interconnecting DER with an area electric power system, and evaluating possible modifications to rate policies and tariffs. As a result, a DER interconnection device has been developed and tested. A workshop reviewed the status and issues of advanced power electronic devices. Software simulations used validated models of distribution circuits that incorporated DER, and tests and measurements of actual circuits with and without DER systems are being conducted to validate these models. Current policies affecting DER were reviewed and rate making policies to support deployment of DER through public utility rates and policies were identified. These advancements are expected to support the continued and expanded use of DER systems.