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 December 2021):

  • 53.5 MW of interconnected solar capacity.
  • 9.6 MW are expected from active reservations.
  • 604 projects statewide serving multifamily affordable housing.
  • Tens of thousands of tenant units participating in Virtual Net Metering as a result of the MASH program. 


VNEM and the MASH Program

The MASH Program, established by AB 217, ran from 2008 to 2021 and had the first virtual net energy metering (VNM or VNEM) tariff in CaliforniaThough the MASH program is closed, the MASH VNM successor tariffs in PG&E, SCE, and SDG&E territory remain open for new enrollments for qualified properties and generation projects. Multifamily properties that satisfy the MASH eligibility criteria and meet all other utility interconnection requirements may utilize the MASH tariff.  Learn more about VNM/VNEM on this page.


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 $108 million 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 CompanySouthern 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 Program Reports and Data

    Third-party Evaluation

    DNV Energy completed its evaluation of the MASH Program. A webinar is scheduled in April 2023 and DNV will share their findings. 

    In 2022, DNV Energy will begin an evaluation of the MASH Program (from 2008-2021) to assess its administration, summarize program activity and determine program benefits (electrical, environmental, and workforce).

    The MASH Program Evaluation Final Research Plan is now available.

    On June 21, 2022, DNV Energy and Energy Division hosted a webinar to review and gather feedback on the MASH Evaluation Draft Research Plan, here are the meeting materials:

    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