• Researched and documented the virtual net metering (VNEM) policy and tariff structure in California.
  • Conducted an assessment of other VNEM policies beyond California to identify lessons learned.
  • Identified obstacles and relevant solutions associated with the currently underutilized virtual net energy metering (NEMV) tariff in order to expand PV adoption beyond traditional commercial and single-family rooftop systems.
  • Developed and implemented a one-year pilot program to raise regional awareness of the NEMV tariff, identify local barriers to adoption, and facilitate solutions to these barriers.
  • Developed and implemented the Multifamily Solar Market Development Plan, which focused on outreach, education, and methods for facilitating multifamily solar installations.
  • Developed numerous online resources for multifamily property owners, contractors, regulators, and other relevant stakeholders.


California is a solar market leader largely due to innovative policies and programs fostered at state and local levels. Despite the many successes of the California solar market, there are portions of the market that still lack easy access to solar energy, particularly renters and businesses in multi-tenant structures. These groups typically have no authority to install solar on their buildings, making it challenging to expand solar PV adoption beyond traditional commercial or single-family rooftop systems.

California features one of the few VNEM tariffs in the country. This tariff allows kilowatt hour credits generated from one solar system to be distributed to numerous utility accounts throughout a property based on a predetermined allocation arrangement, allowing multifamily building tenants to capture the benefits of solar energy without roof space of their own.

The VNEM tariff was initially developed through the California Solar Initiative’s Multifamily Affordable Solar Housing incentive program and was only available to the affordable housing sector. In 2012, the policy was expanded and became available to all multi-tenant and multi-metered buildings. This new expanded tariff, NEMV, applied to various building sectors, including residential, multifamily, commercial, and industrial multi-tenant properties. The uptake levels of the NEMV tariff were initially lackluster, possibly due to a lack of understanding and awareness among customers, an unclear value proposition to property owners, and issues of utility transparency on site qualifications. While NEMV held tremendous opportunity for California’s three million apartment buildings, only a small number of projects had been completed in the state.

The Center for Sustainable Energy (CSE) set out to expand the awareness, effectiveness, and use of NEMV in California and beyond. The project team engaged with solar contractors across California, regulators at the California Public Utility Commission, utility interconnection departments, and key customer segments—including commercial property management associations and multifamily property owners—to identify, catalog, and resolve the barriers to widespread NEMV adoption.

Summaries and Market Assessments

As part of their work, CSE and a supporting project team, published two important research documents that can be leveraged by California and jurisdictions in other states to understand the policy background and structure for the VNEM tariff, best practices in application, eligibility, regulatory considerations, and replicable tariff outreach models.

In 2015, CSE, together with the Interstate Renewable Energy Council (IREC) and the California Solar and Storage Association (formerly the California Solar Energy Industries Association), released the Virtual Net Metering Policy Background and Tariff Summary Report. This report summarizes the policy background that led to the inception of the NEMV tariff, the uptake per investor-owned utility territory in California at the time, eligibility requirements, application processes, associated costs, and similar VNEM or shared solar programs offered in other states. The California NEM-V Market Assessment provides an overview of the current state of the NEMV market in California and identifies potential market developments that could expand NEMV adoption. Through surveys, in-depth interviews with market stakeholders, and data collection, the CSE team established findings related to the market potential for statewide NEMV adoption, the current adoption levels, and the building types currently utilizing the tariff.


Virtual Net Metering Policy Background and Tariff Summary Re... Virtual Net Metering Policy Background and Tariff Summary Report
Author:  CSE

This report summarizes California’s Virtual Net Metering Tariff for general market multi-tenant units and provides an overview of VNM and community solar policies across the country.

California NEM-V Market Assessment California NEM-V Market Assessment
Author:  CSE

This report assesses the current NEM-V Market within CA and highlighting potential market developments that could support greater NEM-V adoption throughout the state.

Pilot Study

Virtual Net Metering Market Development Pilot Study Summary Virtual Net Metering Market Development Pilot Study Summary
Author:  CSE

This summary outlines the goals of the Santa Monica, CA pilot study, focusing on NEM-V tariff outreach, technical, and administrative assistance efforts in a targeted region.

CSE, in collaboration with the Solar Santa Monica Initiative, launched a pilot program in Santa Monica in 2016 to improve awareness of the NEMV tariff throughout the city. CSE published the Virtual Net Metering Market Development – Pilot Study Summary outlining the goals of the study and announcing the selection of Santa Monica as the pilot study site. Working with a select group of local solar developers called Friends of NEMV, the project team hosted contractor training working groups to identify barriers to NEMV tariff deployment. Working groups identified rent-control regulations as a major challenge because property owners would be precluded from collecting additional fees from tenants, including payments for solar energy.


The Santa Monica Market Profile showcases the city’s experience as the pilot study site and highlights policies, actions, and attributes that other cities can replicate when opening up or expanding multifamily solar markets. IREC also developed a template easement agreement to help condo owner-occupants facilitate a VNEM arrangement when seeking to install a shared solar energy system on common areas of a development. This template has been designed specifically for properties located within California investor-owned utility territories, but may be useful in other utility jurisdictions or in states with VNEM policies.


Fostering a Future for Multifamily Solar in Santa Monica, CA Fostering a Future for Multifamily Solar in Santa Monica, CA

The policies, local characteristics, and community engagement that provided a strong foundation for multifamily solar development in Santa Monica, CA.

Form NEM-V Solar Energy System Agreement for Condo Developer... Form NEM-V Solar Energy System Agreement for Condo Developers
Author:  CSE, IREC

This form easement agreement allows condo owners to install a shared solar energy system and receive a share of the benefits of the solar generation.

Multifamily Toolkits and Development Plan

To arm stakeholders with the resources needed to help bolster the multifamily solar market in California and beyond, the project team created several toolkits for contractors and multifamily property owners. These toolkits feature roadmaps, checklists, and worksheets to guide apartment and condominium communities on going solar. Contractor toolkits include interconnection resources, as well as a group of interactive multifamily density maps for targeting outreach regions and acquiring customers.

At the end of 2016, the team released the Multifamily Solar Market Development Plan as a tool to help districts with underutilized VNEM programs bolster the market and to inform policymakers in California and across the country of best practices for designing effective VNEM options for customers, contractors, and utilities. This plan focused on outreach, education, and facilitating installations. It applied lessons learned from the Santa Monica pilot program and explored customer engagement tactics, educational approaches, policy development considerations, and opportunities to spur efficient strategies for enabling installations.

The project team put the plan into practice by implementing a statewide outreach campaign and educational workshop series, as well as launching an online solar marketplace developed by EnergySage for consumers to learn more about multifamily solar, field bids from experienced contractors, and ultimately select a winning installer.


Multifamily Solar Market Development Plan Multifamily Solar Market Development Plan
Author:  CSE

This plan is intended to help policymakers, regulators, local governments, multifamily stakeholders and others in CA and beyond to expand multifamily solar in their jurisdictions.

Next Steps

The project team will continue to work on supporting the VNEM market and other shared solar opportunities in California and beyond. They will monitor relevant policy and regulations, and offer customer service and stakeholder support. The work of each of the project partners can be tracked on their respective websites: http://calssa.org/; www.energycenter.org; and https://irecusa.org/.