How solar panels perform through weather extremes
When we think about harvesting the sun's energy, we might be tempted to envision fields of solar panels in sunny, moderate climates where the skies stay clear and the wind is only a pleasant breeze. In reality, photovoltaic (PV) panels are used all over the world under a variety of weather conditions, some of which present unique challenges for PV panel use.
For example, Chile is home to some of the highest areas of solar irradiance anywhere in the world. However, despite the enormous potential to harvest solar energy as a clean and sustainable source of electricity, few utility providers have actually built any projects, in part due to the unique challenges of extreme weather present in the country.
"The design and construction of a solar panel is particularly important in extreme climates."
Kaltemp, one of Chile's leading home energy providers, decided to use their construction expertise to create a solar array in the Atacama Desert, but the project faced unique challenges. Atacama has an abundance of sun exposure, but it also has an intense climate with severe heat and strong winds. To make the project viable, the utility company would need to use solar panels capable of withstanding and performing well under these conditions. And this has to occur not just for a few years: the panels have to perform at their best capacity all through their 30-year expected lifetime.
The design and construction of a panel is particularly important in extreme climates such as Atacama because the crystalline cells that are used to generate solar power are quite delicate. These cells have to be protected from accidental damage during the manufacturing, transportation, installation and operating life cycles in order to provide continued green energy to the user.
How to combat the challenges of extreme climates
In addition to extreme heat, solar panels are also exposed to cold, moisture, wind and hail, depending on which region of the world the panels are used in. If the weather causes cracking or otherwise compromises the panel's glass sheets, the photovoltaic cells may be damaged and no longer function at their most efficient levels. Any degradation in operational quality may or may not be evident right away, with the drop in panel energy output being visible immediately or over their longer operating lifetime.
The design of Trina Solar panels is such that the reliability out of the box is extremely high. This is achieved by good design and tight control over the production process. On the high volume lines, the use of techniques such as statistical process control (SPC) allows potential problems to be identified and rectified before any material change is seen at the end of the production line or by the customer. Indeed, early failures seldom occur using this technique. The fabled very low failure parts per million (PPM) are usually generated this way. SPC gives rapid feedback from the back-end of the production process to the front end of any potential drift in characteristics that would ultimately result in failures. Corrections are applied before such failures are allowed to occur.
The first step is to design a product that has inherently high reliability built in. This means avoiding all the elements that would contribute to a wear-out mechanism in the product. The second step is to control thoroughly all the materials used to ensure that every element in the design meets the minimum level of performance and toughness before building into the final product. Then the assembly, packaging, and shipping processes have to be tightly controlled and inspected for compliance.
How to test for extreme climates
After all the above elements are implemented properly, industry standard testing and reliability assessments are used as confirmatory processes. All Trina Solar PV panels are sent through rigorous weather testing before they hit the market. Initially, these panels are tested internally in the state-of-the-art State Key Laboratory at the Trina Solar Changzhou headquarters, using criteria that are more stringent than those outlined by the National Electric Code (NEC) and other PV regulatory bodies across the globe. Once the products are deemed fit, they are tested by internationally recognized testing organizations such as TUV Rheinland, Underwriters Laboratories (UL) and the International Electrotechnical Commission (IEC), which offer third-party technical and safety testing of photovoltaic systems. These tests ensure the panels maintain datasheet performance under a variety of extreme elements ranging from high heat to intense humidity to heavy snow load.
"Photovoltaic panels are sent through rigorous weather testing before they hit the market."
Some locations, such as the Atacama Desert, also present additional challenges that require special design features. Using special panel coating, like that found on Trina's DUOMAX Series Dual Glass Module, can make the panels more resistant to the sand, acid or alkali they will be exposed to in sandy areas with high winds. This coating also makes the panels more resistant to hail stones for rainy, temperate climates.
Why Trina Solar?
With over 30 in-house tests and a state of the art research and development lab, Trina goes beyond requirements to deliver the highest quality product to customers. From one end of the supply chain to the other, customers can trust the quality and reliability of Trina.
Trina Solar is the first PV firm to receive the Client Test Data Program (CTDP) Certification from UL. This certification allows Trina Solar laboratories to independently test for and issue UL recognized data, affirming that testing staff expertise, standards and capabilities are of the highest caliber in the PV industry. Trina has partnered with key independent certification laboratories world-wide in order to improve monitoring and standards.
Weather-resistance is also increased by ethylene-vinyl acetate (EVA), a hot-melt adhesive film, used in the manufacturing of solar panels to insulate the PV cells while still allowing for light transmission. The quality of this adhesive film is determined by the presence of the organic compound vinyl acetate. In the past there was no standardized, environmentally friendly way to test the quality of vinyl acetate content in the EVA copolymer applied in photovoltaic panels, leading to inconsistencies among different solar manufacturers.
To solve this issue, in 2015, Trina Solar worked with the Standardization Administration of China and the General Administration of Quality Supervision, Inspection and Quarantine of China to publish a national standard for vinyl acetate testing that will ensure accurate quality testing not only in its own panels but throughout the industry.
Solar panels throughout the world
Relative to industry peers, Trina products have a strong track record of reliability and performance in the field. As a vertically integrated company, Trina tightly controls quality at every step from silicon crystallization to panel deployment in the field. Ultimately, Trina quality is guaranteed by an industry leading warranty for Trina Solar panels that guarantees materials and workmanship for 10 years and power for 30-years on a linear degradation schedule.
Photovoltaic panels represent a long-term investment for project leaders. To provide a return on the upfront cost through energy savings, as well as supply a reliable source of energy, the panels must be able to withstand exposure to the elements for decades.
As global demand for clean, renewable energy continues to rise, manufacturers will continue implementing strenuous product testing of new technologies and designs, allowing solar energy to be harvested from the high desert of Chile to the humid, sandy beaches of Haiti and many snowy, rainy and windy locations in between. Trina Solar will continue to lead the PV industry in technical innovation towards higher quality and reliability.