Overview

Customers of electric utilities have been installing their own photovoltaic (PV) generation equipment in ever increasing numbers since the option became viable in the late 1970s. Owners of these systems feel that the potential for energy independence and low operating costs-- not to mention the environmental benefits-- more than offset the high initial costs. California's implementation of Electric Utility Restructuring in the late 1990s established an incentive program to help level the playing field and promote the installation of PV. Despite Restructuring's dismal failure, the incentive programs offered by the California Energy Commission (Emerging Renewables Rebate Program) and the California Public Utilities Commission (Self Generation Incentive Program) have been remarkably successful (see this powerpoint presentation). Consumers have an ever-increasing-- and bewildering-- selection of equipment and designer/installers from which to choose and precious little independent information to help with the selection. What PV consumers need is a realistic assessment of component and system performance and longevity.

Historically, the consumers of PV equipment-- be they system designers, installation contractors or end users-- have relied on manufacturer literature to judge the performance and suitability of products for various applications. As a result, system designers and installation contractors are confronted with products that have no third-party evaluation and must use their end-user clients as field-test guinea pigs. When equipment performance claims are overly optimistic, the end-user is routinely disappointed with the actual performance. This situation places the contractor in a difficult position of questioning whether the products they use will perform as advertised.

The performance of PV components, especially PV modules, is strongly dependent on operating conditions, so rating and evaluating these components is complex. Not only does characterization require accurate measurement of appropriate parameters, it requires a thorough understanding of the long-term operating issues and the ability to translate and interpret results. Few organizations in the US have credible third-party performance information on PV modules, inverters, and other components relevant to the California market or make that information available to the public.
While component performance is certainly important, system performance, which factors in the interaction of the various components, is even more important. The goals of a properly designed system should be related to performance, safety, reliability, quality of components, ease of installation, code compliance, and cost/value. Compromises the system designer makes to meet an initial cost goal will impact the remaining goals, and may adversely affect life cycle cost-- in other words, affordability.

This project will document the installation and first-year operation of three "large" as well as three "small" commercially-available PV systems.

Evaluation Approach

About the Large Systems

About the Small Systems

Mounting Systems

Inverters