California Solar Initiative—Measurement and Evaluation Reports

The California Solar Initiative (CSI) Measurement and Evaluation (M&E) reports evaluate, measure and verify CSI program impacts to provide reliable information for decision makers, resource planners and program implementers. The reports also help to ensure that the CSI program is being managed in a manner consistent with the intent of the legislature, as well as with the objectives and directives of the California Public Utilities Commission (CPUC).

The goals of the CSI M&E program are to:
  1. Provide credible and objective information on program impacts and performance;
  2. Provide policy and program-related information to ensure achievement of CSI program goals; and
  3. Produce an accurate assessment of future opportunities to further the goals of Senate Bill (SB) 1 and established CPUC objectives and directives.

There are three main categories of CSI M&E reports: progress reports, program evaluation reports and annual program assessments.

Progress Reports

Progress reports are provided by CPUC staff on a quarterly or regular basis to inform the public of the progress of the CSI program. They include information on the most pressing current issues and current program demand information.

Below are links to past CSI CPUC Staff Reports:

Evaluation Reports

Evaluation reports look principally at five elements of the CSI program, covering both solar photovoltaic (PV) and solar thermal technologies: 1) impact studies; 2) system retention and performance studies; 3) market transformation; 4) process studies; and 5) cost-effectiveness evaluations. The reports also include other types of evaluations, including audits, the SB 1-mandated Net Energy Metering (NEM) Cost-Benefit Analysis and any optional studies needed to fully evaluate the CSI program.

Impact Studies

Impact studies provide annual summaries of the impacts of the CSI program. These include the electrical output and demand reduction associated with CSI installations; the performance of CSI installations relative to installed capacity; an estimate of greenhouse gas reductions; quantification of any impact of CSI installations on transmission and distribution system performance, reliability and operations; and project compliance with program requirements.


System Retention and Performance Studies

Retention studies assess the long-term persistence of impacts from technologies installed through the CSI by assessing technical degradation, developing an effective useful life (EUL) for each of the categories of CSI technologies and examining specific operations, including maintenance issues and characteristics, and how they relate to measured system performance and EUL.

Market Transformation Studies

A number of market transformation studies will be conducted over the course of the CSI to provide solar market intelligence to the CPUC. Pursuant to Public Resources Code (PRC) 25780 and SB 1, one of the goals of the CSI is “to install solar energy systems with a generation capacity equivalent of 3,000 megawatts, to establish a self-sufficient solar industry in which solar energy systems are a viable mainstream option for both homes and businesses in 10 years.” The market transformation studies will gauge the success of market transformation with respect to PRC 25780, SB 1 and other similar requirements.

The market studies are categorized into macro-market studies and micro-market studies. Macro-market studies will measure the CSI’s progress toward moving the market toward sustainability by looking at factors such as prices for solar power generation equipment and materials, costs of installation of solar and the number of solar installations on a statewide basis, as well as by regional markets within California. Another type of market study will assess the potential for solar projects achievable through the CSI with the allocated funding.

Micro-market studies will focus on the behaviors or needs of individual market factors as they relate to solar power generation. One area of interest, for example, is the economic factors that may potentially influence a customer’s decision-making process when considering a solar installation.

Process Evaluations

Multiple process evaluations will be conducted over the course of the CSI. These evaluations are in-depth examinations of the design, delivery and operations of the CSI in order to improve the ability of the program to achieve its objectives. Three other types of evaluations will be included under the category of process evaluation. These are administrator comparative assessments, best practices studies and audits.


Cost-Effectiveness Studies

Cost-effectiveness studies are conducted at the end of every second program year to capture the impacts and costs of the preceding two years. The analysis is broken down for each technology category, as well as for the program as a whole. CSI cost-effectiveness is assessed using the CPUC’s adopted cost-benefit methodology, in accordance with CPUC Decision 09-08-026 (PDF, 204 KB).

The 2011 CSI Cost-Effectiveness Evaluation considers the costs and benefits of solar PV and the CSI program from multiple perspectives: participating customers (Participant Test or PCT); program administrators (Program Administrator Cost Test (PACT)); ratepayers (Ratepayer Impact Measure (RIM) test), and society as a whole (Total Resources Cost (TRC) Test and Societal Cost Test (SCT)). From each of these test perspectives, the study quantifies the costs and benefits of solar PV installed through the program.


The CPUC hired Energy and Environmental Economics, Inc. (E3) to perform an analysis of the costs and benefits of net-energy metering (NEM), as required by Public Utility Code 2827 (c)(4). This regulation requires the CPUC to "submit a report to the Governor and the Legislature on the costs and benefits of net energy metering." The report focuses on the quantifiable incremental costs and benefits associated with the NEM mechanism. Costs are quantified in terms of bill credits calculated based on each customer generator's retail rate and the incremental billing costs associated with NEM. Benefits are quantified as the avoided costs of energy and capacity procurement.

Other Studies

Impacts of Distributed Generation

The Impacts of Distributed Generation study provides an overview of the status of California's distributed generation (DG) resources. The report also highlights some of the current challenges and activities around interconnecting these resources to the utility grid, taking into account both CSI-funded PV systems, and non-CSI-funded systems (e.g., PV and other DG technologies funded by the Self-Generation Incentive Program). This was prepared in response to Assembly Bill 578 (Blakeslee, 2008).

Solar Meter and Market Assessment Report

The Solar Meter and Market Assessment Report assesses the metering, monitoring and reporting market for photovoltaic systems in California. The primary topics covered in the report include a survey and evaluation of existing CSI products and services, Advanced Metering Infrastructure (AMI) integration with CSI, and a market assessment of solar metering. The report also includes testing specifications for inverter-integral meters with 5 percent accuracy.

Technical Feasibility

The following three reports were filed by the Program Administrators in response to Ordering Paragraph 7 of Decision 11-07-031 in which the Commission stated: “The CSI Program Administrators (namely Pacific Gas and Electric Company, Southern California Edison Company, and the California Center for Sustainable Energy) shall report within one year of the decision to the Energy Division on the feasibility of using advanced metering infrastructure data to make solar production data available to CSI participants, and ensure a copy of this report is sent to the service list of this rulemaking.”

Technical Potential

  • March 2012 Technical Potential for Local Distributed Photovoltaics in California (Preliminary Assessment) (PDF, 3.72 MB)

  • Annual Program Assessments

    Annual program assessments are prepared by CPUC staff and submitted to the legislature each June. The assessment includes information from the evaluation and progress reports.

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