PVEL Publishes PV Inverter Scorecard

• PVEL has launched its first PV Inverter Scorecard where it tested inverters certified by IEC and/or UL
• It found inconsistency in the performance of various inverters from different brands with more than 20% of products tested were found to have failed safety and reliability tests
• Due to lack of sufficient standards or empirical test data, most inverter buyers go in for brand names which may or may not lead to the perfect buy
• According to the report, manufacturers can underestimate annual maintenance expenses by more than 500% as faulty or problematic inverters are the leading cause of corrective maintenance of a solar PV plant

Solar PV inverters are a key part of any grid-connected solar power plant to get the best out of the system. In its maiden PV Inverter Scorecard, PV Evolution Labs (PVEL), an independent test lab for global downstream solar industry,  found not all inverters match up to the expectations. All tested products for the study, including those that failed, were certified by IEC and/or UL.

According to the scorecard, more than 20% of tested solar inverters failed safety and reliability tests, at least one-third of the products tested failed Arc Fault Testing and over 20% products tested failed Damp Heat and Humidity Freeze tests.

"Predicted inverter field performance and cost of ownership can be overly optimistic compared to actual costs. Existing certification tests are focused on short term wear-out; they're not designed to consider long-term reliability and durability, nor do they evaluate inverters within the PV system as a whole," reads the report.

Several inverter manufacturers have their own in-house reliability testing methods that vary greatly among different companies, and are 'rarely transparent to buyers'. At the same time, some local markets do have their own tests standards but are inconsistently applied. "Due to the lack of sufficient standards or empirical test data, it is common for inverter buyers to rely on brand names, datasheets and warranties rather than independent test data when making inverter purchasing decisions," states the report.

Faulty or problematic inverters are the leading cause of corrective maintenance of a solar PV plant. The report claims manufacturers can underestimate annual maintenance expenses by more than 500%. "The profitability of solar PV projects depends on inverter reliability," said Jenya Meydbray, CEO of PVEL. "When inverters fail, financial losses from reduced energy yield are compounded by ballooning maintenance costs – and even successful warranty claims do not fully compensate asset owners."

It does not name too many companies or which ones failed which tests but names a few of them that were found to be top performers under various categories, such as Delta Schneider, SMA, Fronius, Huawei.

PVEL says its report aims to provide critical testing diligence that's missing in PV inverter procurement scope currently.

PVEL's 2019 PV Inverter Scorecard is available for free download on its website.