Page 14 - North American Clean Energy November/December 2018 Issue

solar energy
Outdoor Exposure
The anatomy of solar PV equipment tests
by Jim Crimmins
Solar photovoltaics (PV) has experienced strong commercial growth in recent years, evolving
from a niche market of small-scale applications
to a mainstream electricity source. This growth provides promise for substantial PV industry market opportunities across the globe. However, reliability and quality continue to be critical elements for
the steady growth; this equipment is expected to reliably perform in the field for 25-plus years, without significant performance degradation, even in extreme environmental conditions.
Many PV modules manufactures claim high performance and high reliability of their products, but those module specifications are restricted to the Standard Test Conditions (STC), that are often not representative of the real conditions in which the PV devices have to operate. A recent study out of Rome confirms that it is important to evaluate
the real behavior of photovoltaic devices in outdoor conditions, through reliable and accurate measurements, and that PV modules performances depend on their technology, location, weather conditions, and mounting configuration.
To address this issue, CSA Group, along with industry stakeholders, worked to create the new CSA C450 “Standardization of Extended Stress Testing” standard. The CSA C450 will be the very first public standard available of its kind. This new standard, ANSI/ CSA C450, will be publically available following the conclusion of the ANSI publication process, which will allow stakeholders the opportunity to contribute to ongoing changes, assuring that all parties’ needs are met. The CSA C450 helps solve many of the challenges the industry was facing when verifying their product’s long-term reliability.
Extended testing helps the industry in the following ways:
• Quality Improvement
There is a consensus that the quality of PV modules supplied to US utility-scale projects has improved significantly over the years, in large part due to the extended stress testing requirements.
• Consumer Awareness of Materials Quality
Project developers and investors have learned that modules of the same module type, but different polymer materials, can behave very differently in the field, which is often not visible in certification testing.
• Manufacturer Awareness of Materials Quality Leading manufacturers now
run internal extended testing
programs to qualify new
designs and materials.
PV performance gradually decreases
with exposure to outdoor conditions. Environmental factors that affect
PV module performance include moisture, UV irradiation, temperature fluctuations, salt, and extreme heat and cold. UV exposure and other factors such as high/low temperature, humidity, and mechanical stress, have been reported to degrade photovoltaic (PV) module materials. It has become increasingly important to evaluate the behavior and performance of various types of PV modules - not only under standard test conditions, but actual
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NOVEMBER•DECEMBER2018 /// www.nacleanenergy.com