CSI Multifamily Affordable Solar Housing (MASH) Program

NOTE: The MASH program is currently closed to new applications.  Please see the section below titled Program Waitlist for more information and please contact the Program Administrator in your service territory with any questions.  Program Administrator contact information can be found below.

The California Solar Initiative's Multifamily Affordable Solar Housing (MASH) Program issues regular semi-annual reports, which provide detailed information on the program's progress.

Recent program milestones include (as of June 2019):

  • 41.9 MW of interconnected solar capacity.
  • 17.9 MW are expected from active reservations.
  • 480 projects statewide serving multifamily affordable housing.
  • $162.3 million in paid incentives to completed projects.
  • Tens of thousands of tenant units participating in Virtual Net Metering as a result of the MASH program. 

About the MASH Program

Established in 2008, the MASH Program provided solar incentives on qualifying affordable housing multifamily dwellings.  MASH is the low-income, multifamily component within the California Solar Initiative program.  In 2013, AB 217 (Bradford) extended the CSI low-income programs by $108million and five years.  The overall goals of the MASH program are to:

  • Stimulate the adoption of solar power in the affordable housing sector;
  • Improve energy utilization and overall quality of affordable housing through the application of solar and energy efficiency technologies;
  • Decrease electricity use and costs without increasing monthly household expenses for affordable housing building occupants; and

Increase awareness and appreciation of the benefits of solar among affordable housing occupants and developers.  In 2013, AB 217 set the additional goals for the program;

  • Maximize the overall benefit to ratepayers;
  • Require participants who receive monetary incentives to enroll in the Energy Savings Assistance (ESA) program.
  • Provide job training and employment opportunities in the solar energy and energy efficiency sectors of the economy.

The MASH program provided fixed, up front, capacity-based incentives for qualifying solar energy systems. The amount of the incentive depends on which Track (1C or 1D) the applicant is eligible for.

Current MASH Incentive Rates

MASH Incentive Rates ($/Watt) 

Track 1C – PV System Offsetting one of the following:

  •  Common Area Load
  • Non-VNM Tenant Load
  • or VNM Tenant Load with <50% Tenant Benefit                                                          


Track 1D – PV System Offsetting:

  • VNM Tenant Load with ≥50% Tenant Benefit



For more information on the CSI MASH Program, please consult the MASH Program Handbook.

For information on the launch of the CSI MASH Program, please read the CPUC regulatory decision that authorized the program and the January 2015 decision that reauthorized the program.You may also contact the CPUC's Distributed Generation team with regulatory questions.

Program Administrators

The MASH program is managed by the Program Administrators of the General Market CSI Program: Pacific Gas & Electric Company, Southern California Edison, and The Center for Sustainable Energy in San Diego Gas & Electric territory.  Please contact the Program Managers with eligibility questions, program applications, solar and energy efficiency questions and in identifying loans, grants and other financing options.  The MASH Program Administrators can be contacted at:

  • Pacific Gas & Electric - Solar Customer Service Center 1-877-743-4112, Solar Hotline 415-973-3480
  • Southern California Edison - Contact 866-584-7436
  • In San Diego Gas & Electric territory - Contact the California Center for Sustainable Energy at 858-244-1177 or MASH@energycenter.org  

MASH Program Reports and Data

Third-party Evaluation

In January 2016, Navigant Consulting completed its evaluation of CSI SASH and MASH program design, delivery, operations and impact for program years 2011-2013 and released two reports:  a program administrator and market assessment, and an impact and cost-benefit analysis.  These program evaluations build upon the previous SASH and MASH studies completed in 2011, and also available upon the previous SASH and MASH studies completed in 2011, and also available through links below.  On January 28, 2016, the Navigant Consulting issued the California Solar Initiative SASH and MASH Market and Program Administrator Assessment, Programs Years 2011-2013.

On January 28, 2016, Navigant Consulting issued the California Solar Initiative SASH and MASH Market and Program Administrator Assessment, Programs Years 2011-2013.

On August 4, 2011, Navigant Consulting issued the CSI SASH and MASH Impact and Cost Benefit Report.

On June 10, 2011, Navigant Consulting issued the CSI MASH Biennial Report

On April 5, 2011, Navigant Consulting issued the CSI SASH and MASH Program Administrator Performance Assessment Report, which provides an evaluation of the MASH Program."

On April 1, 2011, Navigant Consulting issued the SASH program.  The CSI SASH and MASH Market Assessment Report, which provides an evaluation of the MASH program.

Semi-annual Reports

To access the MASH Semi-annual Progress Reports submitted by the Program Administrators that includes information on budget allocation, program expenses and progress on track incentives, both as a total and by utility, please visit here.

Low-Income Solar Data Set

In November 2014, the CPUC voted to update reporting requirements for MASH projects.  D.14-11-001 transferred data collection responsibilities from the CSI to the Net Energy Metering (NEM) Interconnection Process.  To view public data reports, please visit the California Distributed Generation Statistics website.

MASH Program Regulatory Proceeding Documents

Immigration Guide