The solar photovoltaic (PV) panel industry is in the midst of a major transformation. Technologies such as bifacial modules and passivated emitter rear cells (aka PERCs) have gained traction, while the overall costs of solar energy per watt and per system have continued their long-term declines.

According to EnergySage, solar panel systems cost 6 percent less year-over-year in May 2018. Meanwhile, gigawatts of installed capacity are being added each year. In the U.S, 10 gigawatts were installed in 2017, and the Solar Energy Industries Association expects total installed capacity to more than double over the next five years.

Granted, there are still some challenges ahead for PV vendors and their customers. These include ensuring acceptable performance from panel innovations and navigating ongoing changes in regulations and trade policies across the globe.

Since 2014, DNV GL has published an annual Scorecard to track the progress of different solar PV manufacturers in developing high-quality, reliable modules and accessories. In the 2018 edition, Trina Solar became one of only three vendors to receive the Top Performer distinction four times.

The DNV GL Scorecard: What does it measure and test for?

The Scorecard itself is based on a separate set of measures known as the Production Qualification Program (PQP). The PQP is designed to give solar buyers and power plant investors reliable data on solar product quality and durability, so that they can make informed decisions on which suppliers to work with.

Here are a few of its specific tests and metrics it includes:

Thermal cycling

Solar module materials routinely expand and contract based on changes in environmental temperature and irradiance. Such changes can adversely affect performance by introducing additional stress on specific components.

A thermal cycling test will subject modules to extreme temperatures and measure the resulting degree of power degradation. The median loss in the 2018 test ws 1.6 percent, with the worst performed coming in at 8.8 percent.

Damp heat

In addition to temperature, PV panels are also affected by humidity. The PV damp heat test gauges the long-term impact of both conditions on modules. It is designed to measure panel response een in temperate climates that do not feature extreme temperatures and excessive humidity levels.

As per the PQP, the damp heat test lasts for 2,000 hours to differentiate average and top performers. Median power degradation was 2.5 percent, up from only 0.9 percent in the two previous Scorecards.

Dynamic mechanical load

The dynamic mechanical load (DML) test evaluates a solar module resilience in the face of wind and snow. However, it tests the modules by proxy, using 1,000 cycles of alternate loading while they are in the mounting positions chosen by their manufacturers.

The results of the DML testing showed some of the least variance of all tests performed. Median degradation was only 1.2 percent and had declined from previous years. The bigger drop was at the low end, with even the bottom performer seeing only 3.1 percent degradation compared to more than 11 percent in 2017.

Potential induced degradation

The potential induced degradation (PID) test is designed for ungrounded and high-voltage systems, which have become more commonly deployed over time. PID is the result of biases in internal PV circuits that lead to increased leakage currents.

Modules are tested by being exposed to voltage biases equal to their respective voltage ratings. PID tests results were varied, from a median of 1.4 percent to a low of 7.4 percent. In past evaluations, the lowest performer had exceeded 92 percent loss on two occasions, so great improvements have been made in the ensuing years.

Trina Solar: Our module quality and durability speak for themselves

As a solar PV manufacturer with over 20 years of experience in the industry, Trina Solar is proud to receive this recognition from DNV GL for the excellent performance of modules in the above tests. Please visit our Products and Solutions page to learn more.