The Bureau of Energy Efficiency (BEE) has announced a Standards and Labeling Program for grid-connected solar inverters without storage to indicate their overall efficiency.

The current minimum energy performance standard will be in force from March 15, 2024, to December 31, 2025.

Introducing the endorsement label for grid-connected solar inverters is expected to lead to significant benefits, including an estimated energy saving of 21.1 billion kWh from the financial year 2024-25 to 2033-34. Additionally, it could substantially decrease CO2 emissions, with a projected reduction of 15.1 million tons over the same period.

All single-phase and three-phase grid-connected solar inverters without storage, with a rated output power of up to 100 kW, manufactured, imported, or sold in India must participate in the program. However, only Bureau of Indian Standards (BIS)-certified solar inverters who comply with IS 16221-2:2015 are eligible to participate in the program.

BEE found that most grid-connected solar inverters in India achieve peak efficiencies ranging from 94% to 99%. The data shows that their rated capacity increases so does their efficiency. In a review of 450 models, 445 operated with an efficiency above 97%.

Given this small range in efficiency levels, the Bureau has decided to introduce an endorsement label instead of the usual star labeling for these solar inverters. The label will contain the overall efficiency percentage, label period, product name, manufacturer name, model number, manufacturing year, and rated capacity in kW.

The minimum overall efficiency requirement of the inverter will be based on static maximum power point tracking (MPPT) efficiency measurement and steady-state conversion efficiency. The program does not cover the dynamic MPPT efficiency prescribed in IS 17980:2022/IEC 62891:2020. The testing does not cover the dynamic MPPT efficiency.

The minimum energy performance standards for grid-connected solar inverters are:

Fees

Applicants must pay a security deposit of ₹100,000 (~$1,203) for each registration. Small-scale industries only need to pay ₹25,000 (~$300) if they provide a valid registration certificate.

There’s a fee of ₹2,000 (~$24) for each model applying for label permission, but this fee is not required until September 30, 2024. No fee is needed for renewing the label permission.

A labeling fee of ₹5 (~$0.06)/ kW is charged for each solar inverter, but this is waived until March 31, 2025.

Sampling process

BEE or an assigned agency will randomly pick samples from the manufacturer’s authorized dealers, retailers, or e-market platforms for initial testing.

If a sample fails the initial test, a second test is conducted with twice the number of samples of the same model bought by the Bureau or its designated agency. The manufacturer is informed about the failure and advised to prepay for the cost of the second round of samples, testing, and transport.

If the manufacturer doesn’t pay the expenses, BEE will proceed with the second test and halt any new applications from the manufacturer until dues are cleared.

A second set of samples is randomly picked from the market. Both sets must pass the test. The manufacturer is informed about the testing date and may attend; if not, BEE will proceed, and the results will be final.

The inverter model is deemed non-compliant if any sample fails in the second test. The manufacturer must then:

• Withdraw all non-compliant stock from the market within two months and either remove the endorsement label or correct the defects.
• Announce the non-compliance publicly in national or regional newspapers and other suitable media within three months.
• Submit a report to BEE or the designated agency within ten days after the two months detailing compliance actions taken.

Sample testing for compliance of solar inverters will be carried out in laboratories that are either BIS–recognized or accredited by the National Accreditation Board for Testing and Calibration Laboratory.

Recently, Mercom hosted a webinar highlighting how high-capacity string inverters could help save costs for large-scale solar projects.

Last October, the Indian government initiated a Standards and Labelling Program for solar modules.