The California Solar Initiative's RD&D Program has now concluded after operating since 2008 through 2016. All solicitations and research projects are now complete.



 Program overview  + Research briefs       

 [25 MB]
 Program overview  [13 MB]

 Research briefs  (high resolution)                     

 [44 MB]

For more information on the research projects and resulting reports please review the section below. All completed final reports are also available separately for review and download. 

FINAL REPORTS for completed projects along with individual research briefs can be found here.


Funded Projects

This is a database of projects funded by the CSI RD&D. The project summaries are listed alphabetically below. You may also choose a subset of projects by clicking a keyword, or using the search function.

Analysis of High-Penetration Levels of PV into the Distribution Grid in California

Current Highlights:
  • Final Project Report. 14 June 2014.  PDF  (7.8 MB)

Project Information

Solicitation: Solicitation 1
Target Area: Grid Integration
Awardee: National Renewable Energy Laboratory (through SCE)
CSI Funding: $1,600,000
Match Funding: $1,400,000
Start Date: November 2010
End Date: November 2013
Status: Complete

Contact Information

Principal Investigator Name: Barry Mather / Sunil Shaw
Principal Investigator Email: barry.mather @ nrel.gov / sunil.shah @ sce.com
Principal Investigator Phone: 303-275-4378
Grant Manager Name: Stephan Barsun
Grant Manager Email: stephan.barsun @ itron.com
Grant Manager Phone: 509-891-3187

Project Summary

Sustaining high growth rates in the photovoltaic (PV) industry requires being able to successfully integrate PV into the electric power system while maintaining reliability. This project addresses the issues with integrating high levels of PV into the electrical distribution system by fully examining the issues, developing solutions, and transitioning those solutions to the field for large-scale deployment.

California regulators approved Southern California Edison (SCE)'s plan to install 500 MW of distributed solar in its service territory over the next five years. This installation represents the highest level of distributed PV in any utility service territory in the United States and has several distribution circuits with high penetrations of PV. Substantial efforts must be undertaken to ensure that SCE can integrate this amount of PV into its distribution systems while maintaining system reliability.

To understand the impact of these new PV installations on the distribution grid, the project team conducted modeling and simulation, laboratory testing, and field demonstrations of the effect of high penetrations of PV on electrical distribution systems.

The project team first defined a number of factors and impacts related to introducing high penetration PV systems into the electrical distribution system and defined hardware and software solutions. The National Renewable Energy Laboratory (NREL) conducted laboratory testing on advanced inverters and control systems. These advanced systems were installed on projects in the SCE service territory to help eliminate issues that arise due to high penetration levels of PV, such as voltage regulation or unintentional islanding. The NREL testing consisted of developing the functional requirements and then implementing them in hardware.

The final results from this project are summarized into technical reports on best practices, designed to instruct utilities on how to integrate high levels of distributed PV systems into the electrical distribution grid. This will accelerate the placement of high levels of PV into existing distribution circuits and identify new circuit configurations that will help increase PV penetration levels.

Deliverables and Documents


  • Final Project Report. 14 June 2014. NREL/SCE High Penetration PV Integration Project: FY13 Annual Report. PDF  (7.8 MB).

  • NREL/SCE High-Penetration PV Integration Project: Report on Field Demonstration of Advanced Inverter Functionality in Fontana, CA. Mather, Barry. August 2014.  PDF (440 KB)

  • Comparative Analysis of Time-Series Studies and Transient Simulations for Impact Assessment of PV Integration on Reduced IEEE 8500 Node Feeder. Paradis, D., F. Katiraei, Sr. Member, and B. Mather, Member-IEEE. IEEE. 2013.  PDF (427 KB)

  • NREL PHIL Inverter Test Report: Analysis of High-Penetration Levels of PV into the Distribution Grid in California. March 12—March 16, 2012. Matt Kromer, Satcon Technology Corp., Boston, MA. NREL/SR-5500-57786. June 2013.  PDF or http://www.nrel.gov/docs/fy13osti/57786.pdf

  • SCE/NREL High-Penetration-PV Year-1 Report. Jun 2011. PDF

  • SCE/NREL (Interim Rpt) Advanced Inverter Technology for High Penetration Levels of PV Generation in Distribution Systems. Nov 29, 2011. PDF

  • Integrating High Penetrations of PV into Southern California PDF (122 KB)



  • Initial Project Presentation. Jul 22, 2010. PDF (105 KB)

  • SCE High Penetration PV Integration Project. Poster. Jun 11, 2012. DOE SunShot Summit.PDF (2.6 MB)

  • Final Project Presentation and Webinar: Analysis of High-Penetration Levels of PV into the Distribution Grid in California: NREL/SCE High-Penetration PV Grid Integration Project. Barry Mather Ph.D. (NREL), Sunil Shah (SCE), Rich Seguin (Elec. Dist. Design), Farid Katiraei Ph.D. (Quanta Technology). December 17, 2013.

Presentation PDF (3.8 MB)
Webinar WMV (122 MB)

Project Activities

 December 17, 2013  Final Presentation delivered.

Project Links