Tamil Nadu Regulator Clarifies Billing Mechanism for Rooftop Solar Prosumers

The Tamil Nadu Electricity Regulatory Commission (TNERC) has issued draft amendments to the Electricity Supply Code 2004 for bi-directional meter billing for rooftop solar systems.

Stakeholders can submit their comments and suggestions within 15 days of the publication of the notification on the TNERC website.

The Commission has added a new clause for assessing billing in cases where there is no bi-directional meter, or the bi-directional meter is defective in low tension (LT) rooftop services.

Import of Energy


According to the new clause, if there is no bi-directional meter or the meter is defective, the amount of electricity imported during the period will be determined by taking the average imported during the preceding four months. The conditions regarding the import of electricity during the said four months should not be different from those that prevailed during the billing period.

If the bi-directional meter becomes defective immediately after it is installed, the amount of electricity imported will be calculated by considering the average imported during the next four months after the installation of a new meter. The prosumer will be charged monthly minimum charges for the defective period, and the actual charges will be recovered after adjusting the amount collected provisionally.

If the conditions regarding the import of electricity during the billing period are different, the assessment will be made based on any consecutive four months during the last 12 months when the conditions were similar.

If it is not possible to select a set of four months, the electricity imported will be assessed by the distribution engineer-in-charge.

Export of Energy

In the case of export of energy, if the meter becomes defective after previous assessments for four months, the amount exported during the billing period will be determined by taking the average of the exported energy during the last four months.

If the bi-directional meter becomes defective immediately after installation, the energy exported to the grid during the billing period will be determined by taking the average exported during the successive four months after the installation of a new meter. Until that time, the prosumer will be charged as follows:

The total energy exported during the period with no bi-directional meter or the meter is defective = 2 x (defective period in days) x (installed capacity of the solar power plant in kW).

In case the prosumer does not agree with the engineer’s assessment, the matter may be referred to the next higher-level officer of the licensee.

Recently, the Ministry of Power issued the Electricity (Rights of Consumers) Rules, 2020 laying down power consumers’ rights to minimum quality standards. One noteworthy provision in the rules mandates net metering for loads up to 10 kW and gross metering for loads greater than 10 kW.

Previously, Mercom reported that TNERC had issued new net metering guidelines for solar rooftop consumers as part of its Solar Policy 2019. The net-metering mechanism was one of the key features of the policy that was expected to help the state achieve its installation goals.

Net metering has been the primary impediment for rooftop growth in the country. Even though the net metering policy exists in most states, implementation has been rocky. Mostly, DISCOMs are vehemently opposed to net metering across states. The primary reason for this aversion to net metering is that it deprives DISCOMs of the opportunity to earn more revenue from premium consumers.