Testing Times

Inadequate lab facilities and high costs remain key issues

With around 35 GW of solar power capacity installed and more than this in the pipeline for the next two years, the quality aspect of these projects has become a cause for concern for developers as well as investors. Given the project life of 25 years, it is important to ensure that solar plants are built using quality components. The quality of inverters and all other components, such as inverters, modules, mounting structures, cables, connectors and junction boxes, directly impacts the cost of energy, revenues and return on investment for project developers and operators. Quality control, therefore, assumes paramount importance to generate the best yields from a solar power plant.

The emphasis initially was on ensuring good quality of PV modules but over time the quality consideration regarding inverters and other equipment too has taken centre stage. However, the implementation of relevant standards for inverters has been tardy. As a result, manufacturers have faced many challenges such as high costs of testing and delays in testing on account of limited labs in the country. The Ministry of New and Renewable Energy (MNRE) has tried to address some of these challenges through regulations but issues pertaining to limited testing labs still remain.

Guidelines and standards

In 2018, the MNRE issued guidelines for conducting tests on power and utility-interconnected PV inverters. These guidelines made the registration of inverters with the Bureau of Indian Standards (BIS) compulsory. This was in line with the Solar Photovoltaics, Systems, Devices and Component Goods Order, 2017 that required testing of inverters in labs.

In April 2019, the MNRE issued guidelines for grouping solar inverters before conducting quality control tests in labs. These guidelines were approved in August 2019.

The new guidelines apply to all solar PV-based off-grid, grid-connected and hybrid inverters of capacities up to 150 kW. As per the new guidelines, there are several inverters of the same size, rating and type, and these can be grouped together for sample testing in labs. The product family could be granted approval based on the testing of one model. All models that have similar hardware and software characteristics are grouped in a single product family.

The grouping of inverters helps in reducing lab testing time and in resolving issues surrounding the dearth of testing labs and the high cost of testing individual inverters.

Delays in decision-making

With the industry seeking more time for compliance, owing to issues related to hefty testing fees and the lack of labs, the government has no option but to keep extending the self-certification deadline for solar inverters.

In January 2020, the MNRE further extended the deadline for self-certification of solar inverters by six months, from December 31, 2019 to June 30, 2020. The deadline for BIS certification of solar inverters was extended twice before, from June 30, 2019 to September 30, 2019, and from January 30, 2019 to June 30, 2019.

However, the self-certification deadline is subject to the condition that inverter manufacturers have valid International Electrotechnical Commission accreditation and test reports from international testing labs.

Challenges for inverter manufacturers

The industry has welcomed the solar inverter quality standards introduced by the government. However, a number of inverter developers are complaining that the cost of certification is extremely high, and only a handful of players with deep pockets can bear such high expenses. Another key challenge is repetitive testing – the first in the home country where inverters are manufactured and the second in the country where they are used. Many inverter manufacturers have the certification complying with the European norms, for instance European IEC certificates, on which the Indian BIS standards are based. This repeat testing has put an additional cost burden on inverter manufacturers.

The key bottlenecks for inverter manufacturers are the lack of labs, inadequate testing facilities and paucity of a skilled workforce, unreasonable cost of testing, and confusion over MNRE notifications. These issues are likely to continue until new testing labs are set up or existing ones are upgraded and equipped with better facilities and a skilled workforce.

By Sarthak Takyar


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