U.S. Department of Energy

Distribution Grid Integration

The DOE Systems Integration team funds distribution grid integration research and development (R&D) activities to address the technical issues that surround distribution grid planning, operations, and reliability. The utility grid was designed to accommodate one-way power flow from a central generation station to loads. The introduction of distributed power sources, such as rooftop photovoltaic (PV) systems, can influence electricity current flows on the distribution circuit and impact system protection. More information on distribution grid integration is available in the Distribution section of the High Penetration Solar Portal.

Within the SunShot Systems Integration activities, distribution grid integration R&D is being funded through DOE national laboratories and competitive awards.

National Laboratory R&D

The National Renewable Energy Laboratory (NREL) and Sandia National Laboratories, with funding from DOE, are providing critical R&D activities in the areas of distribution circuit modeling, monitoring, analysis and visualization, PV inverter modeling, testing and advanced inverter functionality demonstration, interconnection codes and standards leadership and development, and workforce education and stakeholder engagement.

Approach

There is an industry need for significant upgrades to the analytical tools used by utility distribution planners and operators. Utility planners need to accurately model distribution feeders and develop better dynamic models of how different inverter designs will perform during both normal and abnormal conditions. NREL and Sandia are developing analysis, modeling, and simulation tools and conducting technical analysis on high penetration scenarios for PV systems to understand their impact on the electric grid.

Higher levels of PV penetration and larger PV plant sizes are forcing many interconnection requests into further study, often creating delays and increasing costs. Case studies of high penetration distribution feeders in the United States and Europe clearly indicate that there are methods for integrating PV systems at higher penetration levels, and the NREL and Sandia research teams support the development of solutions that will reduce delays and costs.

Advanced inverter functionality will allow safe and cost-effective high penetration PV deployment on distribution systems by self-mitigating the voltage control and protection coordination issues that arise with high penetration scenarios. NREL and Sandia are accelerating the development and widespread adoption of advanced inverter capabilities.

Innovation

NREL and Sandia efforts focus on:

  • Developing advanced distribution system modeling, monitoring, and visualization tools for use in utility operations and incorporating them into open-source distribution planning tools
  • Developing PV modeling tools and methods to systematically simulate high-resolution solar output data and publish solar variability data sets for use by utility planners performing grid interconnection studies
  • Accelerating the development and widespread adoption of advanced inverter capabilities (i.e., volt-VAR control, voltage ride-through, and anti-islanding functionality) while maintaining SunShot price targets for PV power electronics
  • Improving small-generation interconnection processes in the United States to expedite PV interconnections by defining new screening criteria based on a strong technical foundation
  • Developing metrics for advanced feeder hosting capacity and developing interconnection screens by utilizing distribution circuit monitoring, modeling the distribution circuit impacts of high penetration PV scenarios, and completing technical integration studies
  • Leading the development of interconnection standards and codes with a focus on high penetration distribution circuits and advanced PV inverter technology and communications applications
  • Utilizing megawatt-scale PV integration test laboratories for testing, characterization, and validation of advanced inverter functions and control schemes for use in high penetration distribution circuits
  • Providing technical educational material, training, and guidebooks for utility engineers, universities, policymakers, and PV stakeholder groups to ensure safe and reliable PV system interconnections in high penetration environments
  • Engaging key stakeholders, such as electric utilities, state public utility commissions, PV manufacturers, PV developers, and installers.

The goal of these efforts is to reduce barriers to integrating high penetration PV on distribution circuits. This results in lower installed costs and improved interconnection procedures, while maintaining safe, reliable, and cost-effective distribution system operation. Improving distributed PV grid integration is essential to lowering the balance of system costs identified by the SunShot Initiative, and will minimize the interconnection costs in high penetration circuits.

Competitive Awards

The following competitive solicitations represent recent and ongoing distribution grid integration research efforts:

Learn about other DOE competitive awards for systems integration research that are in progress.