Christina Jennings

PV module performance at PG&E

Outdoor performance is evaluated for a single-crystal, a polycrystalline, a ribbon, and three amorphous silicon modules. To compare the performance of PV modules, a model relating output power to irradiance and ambient temperature is developed. During typical midday conditions, crystalline silicon efficiencies are 9% to 12% while amorphous silicon efficiencies are 4% to 5%; performance estimated using the model is within +or-5% (relative) of measured performance. Crystalline silicon efficiencies are highest during the winter and lowest during the summer. Amorphous silicon efficiencies are less sensitive than crystalline silicon efficiencies to changes in ambient temperature. Technology improvements are evident when comparing the performance of these modules to that of older modules.<<ETX>>

Carrisa Plains PV power plant performance

The authors summarize the performance of the worlds largest PV (photovoltaic) power plant (the one at Carrisa Plains, California) for 1984-1989. Although the plant has high availability, energy production efficiency has declined at the rate of 8-12% per year since 1986. Based on the data, it is difficult to provide a thorough explanation for the steady decline in Carrisa Plains PV performance. The core problem has largely been attributed to the thermal oxidation of ethylene vinyl acetate PV cell encapsulant caused by elevated temperatures of the mirrored segments. The PV modules, originally dark blue in color, are now brown. A number of possibilities exist which may contribute to the plants decline in power output, such as mismatching, leakage currents, inappropriate inverter operating point, and changes in maintenance. Performance results of the mirrored and nonmirrored segments are presented These results indicate that the nonmirrored segment is performing well with minimal efficiency degradation and low operation and maintenance costs.<<ETX>>

PV module performance outdoors at PG&E

The 1989 performances of 38 PV (photovoltaic) modules installed outdoors at PG&Es PV Test Facility in San Ramon, California, are evaluated. Performance improvements with each generation of PV modules indicate the progress of PV. Efficiencies greater than 12% have been measured. Within each PV technology, module performance tends to follow parallel month-to-month trends. Even after initial degradation, amorphous silicon modules have the greatest month-to-month variations. Monthly averaged efficiency is within +or-10% of annually averaged efficiency for amorphous silicon modules after initial performance degradation and within +or-6% for the single-crystal silicon, polycrystalline silicon, ribbon silicon, bifacial silicon, and concentrating silicon modules evaluated.<<ETX>>

Thin-film PV performance at PG&E

Abstract The outdoor performance of photovoltaic (PV) modules is monitored at PG&Es PV Test Facility in San Ramon, CA. This paper evaluates the performance through mid-1989 of commercially available amorphous silicon (a-Si) PV modules manufactured by ARCO Solar, Chronar, Solarex, Sovonics, and Utility Power Group. All of the modules have exhibited efficiency degradation on initial sun exposure. Module efficiencies are initially 5 – 6% and appear to stabilize around 4% after 1 yr of outdoor exposure. The a-Si modules installed in 1985 which initially operated at 5% efficiency have maintained 4% efficiency for the last 3 yrs.

PVUSA-the first decade of experience

Photovoltaics for Utility Scale Applications (PVUSA) is a national cooperative research and development project with a mission to acquire information through field installation and testing of grid-connected photovoltaic (PV) technologies and to provide the information to utilities and other participants. This paper updates the projects progress and summarizes performance, cost, and value results obtained in the 10 years since project inception.

PG&E experience with a 10-kW commercial rooftop PV system

Pacific Gas and Electric Company (PG&E) is one of eleven electric utilities that participated in the first phase of the US Environmental Protection Agencys Photovoltaic Demand-Side Management (PV-DSM) Program. PG&E participation involved the December 1993 installation and subsequent testing of a 10 kW/sub AC/ PV power system on a PG&E-owned building in San Ramon, California, USA. The performance of the system supports the technical readiness of rooftop-mounted PV systems.

Thin film silicon photovoltaic module performance assessment

This report evaluates the performance through December, 1986 of 15 commercially‐available thin film silicon‐hydrogen alloy PV modules manufactured by ARCO Solar, Chronar, ECD/Sovonics, and Solarex. Advances in the technology are indicated by the performance improvements associated with each generation of thin film silicon‐hydrogen alloy PV modules introduced to the commercial market. Mounted at a 30 degree tilt facing due south, all of the thin film PV modules under evaluation have experienced decreased efficiency and fill factor on initial sun exposure. Midday efficiency tends to be highest during the summer and lowest during the winter. The seasonal change in midday air mass from 1.0 during the summer to 1.4 during the winter is among the factors that counteract the temperature effects and cause lowered efficiency and fill factor values during the winter.

Photovoltaic research at Pacific Gas and Electric Company

Cost-effective photovoltaic (PV) use by utilities is anticipated to extend beyond todays small, stand-alone installations to grid support, villages and islands, and customer-sited applications before PV enters peaking and bulk power markets. PV research at Pacific Gas and Electric Company has evolved since 1980 to demonstrate the technology and stimulate utility consideration and acceptance of PV.<<ETX>>

AC photovoltaic module magnetic fields

Implementation of alternating current (AC) photovoltaic (PV) modules, particularly for distributed applications such as PV rooftops and facades, may be slowed by public concern about electric and magnetic fields (EMF). This paper documents magnetic field measurements on an AC PV module, complementing EMF research on direct current PV modules conducted by PG&E in 1993. Although not comprehensive, the PV EMF data indicate that 60 Hz magnetic fields (the EMF type of greatest public concern) from PV modules are comparable to, or significantly less than, those from household appliances. Given the present EMF research knowledge, AC PV module EMF may not merit considerable concern.

STAND-ALONE PHOTOVOLTAICS IN CALIFORNIA

ABSTRACT To quantify stand-alone photovoltaic (PV) applications in the state of California, a survey of major suppliers of PV systems and components was conducted. As of December 1989, approximately 1,790 kilowatts of stand-alone PV systems were installed in California. PV module sales in California have increased 29% per year since 1986. The leading stand-alone PV applications are residential (62% of the total installed capacity), communications (13%), and billboard lighting (8%).