India Mandates Minimum Efficiency And Labelling Rules For Solar Inverters Up To 100 kW

The Government of India has issued an important notification introducing new energy consumption standards for grid-connected solar inverters across the country. The notification, published on 12 November 2025, has been released under the powers given to the Central Government through the Energy Conservation Act, 2001. The Ministry of Power, after consulting the Bureau of Energy Efficiency (BEE), has formally defined how solar inverters up to 100 kW should perform and how their efficiency will be measured and labelled.

According to the notification, the new rules apply to both single-phase and three-phase grid-connected solar inverters that have an output voltage of 230 V AC for single-phase and up to 415 V AC for three-phase. These inverters are required to meet specific energy performance standards based on the Indian Standard IS 17980:2022 or its equivalent international standard IEC 62891:2020. The standards focus mainly on conversion efficiency and maximum power point tracking (MPPT) efficiency, which together determine the overall efficiency of the inverter.

The notification explains how these efficiencies are defined. Conversion efficiency is described as the ratio of energy delivered at the AC terminal to the energy received at the DC terminal. MPPT efficiency measures how effectively the inverter draws power at the maximum power point from a PV simulator. Overall efficiency is calculated by combining these two values. The government has provided a formula to show this relationship clearly, ensuring that manufacturers follow a uniform method of calculation.

One of the most important parts of the notification is the table that specifies the minimum overall efficiency required for inverters of different rated output capacities. These requirements will be valid from 1 January 2026 to 31 December 2027. For inverters below 1 kW, the minimum efficiency must be 92 percent. The standard increases gradually for higher capacities, reaching 98 percent for inverters above 20 kW. There is no negative tolerance allowed, which means every tested inverter must meet or exceed the minimum efficiency threshold without exception.

The government has also specified the pre-qualification criteria for manufacturers who want to participate in the BEE labelling programme. Only inverters compliant with the Bureau of Indian Standards will be eligible. Every inverter must be tested according to the latest version of IS 17980:2022, and the test reports must come from laboratories accredited by recognised national or international accreditation bodies, or by the National Institute of Solar Energy. This ensures that all test results are reliable and consistent.

The notification includes a detailed format for reporting test results, covering general information about the laboratory, details of the inverter sample tested, test conditions, and final results for MPPT efficiency, conversion efficiency, and overall efficiency. This helps maintain transparency and uniformity in the testing process.

A separate notification issued on the same date further directs that all qualifying grid-connected solar inverters without storage must display label particulars as specified by the Bureau of Energy Efficiency. This applies to inverters up to 100 kW that fall under the scope of the same Indian Standard. The government aims to ensure that consumers receive clear and accurate information about the performance of the solar inverters they purchase.

These notifications mark a significant step towards standardising solar inverter performance in India and promoting higher energy efficiency in renewable energy systems.