The Tamil Nadu Electricity Regulatory Commission (TNERC) has set a generic tariff of ₹3.61 (~$0.049)/kWh for grid-connected solar power projects for capacity ranging from 1kW to 10 kW, ₹3.37 (~$0.045)/kWh for 11 kW-150 kW, and ₹3.10 (~$0.042)/kWh for 151 kW-999 kW.

The ‘Generic Tariff order for Grid Interactive Solar Photovoltaic (PV) Energy Generating Systems’ is effective from October 22. The tariffs will be applicable for all consumer categories and will be valid until March 31, 2023.

The tariffs will apply to grid-connected solar energy systems commissioned during the control period specified in the order except for programs like Pradhan Mantri Kisan Urja Suraksha Evam Utthan Mahabhiyan (PM-KUSUM), for which the Commission will issue specific orders.

The Commission issued a consultative paper on August 17, 2021, inviting stakeholders to comment on the three categories of metering mechanisms, consumers’ eligibility, and tariff determination.

The Commission arrived at the tariffs by taking into consideration the following parameters:

Time-of-the-Day Tariffs

The Commission introduced the time-of-the-day tariffs under which prosumers would be incentivized to install energy storage for their use or to feed into the grid during peak hours.

The time-of-the-tariffs will be higher than the LCOE (Levelized Cost of Energy) based tariffs and apply during the evening peak hours.

The Commission set a peak hour time-of-the-day tariff of ₹4.33 (~$0.058)/kWh for system capacities up to 10 kW, ₹4.04 (~$0.055)/kWh for capacities in the range of 11 kW to 150 kW, and ₹3.72 (~$0.051)/kWh for 151 kW to 999 kW systems.

Network or Wheeling Charges

To encourage the growth of solar power in the domestic sector, a network or wheeling charge of 20% will be applicable for domestic consumers of up to 10 KW load and 75% for consumers with a load of more than 10 kW.

The network or wheeling charges have been set at ₹0.83 (~$0.011)/kWh for high tension (HT) consumers and ₹1.27 (~$0.017)/kWh for low tension (LT) consumers.

Net Metering and Gross Metering

All domestic consumers are eligible for net metering up to sanctioned load/contracted demand. Domestic consumers have an additional option of choosing the net feed-in mechanism.

The solar energy net billing or net feed-in mechanism will be available to all electricity consumer categories (except agriculture) irrespective of tariff and voltage levels up to sanctioned load/contracted demand, subject to a maximum capacity of 999 kW.

Existing and new consumers of all categories except domestic and solar energy generators are eligible for gross metering mechanism irrespective of tariff. The minimum size of the solar system that can be set up under the gross metering mechanism will be 151 kW up to a maximum capacity of 999 kW.

Energy Billing and Accounting

Net metering

An eligible consumer under the net metering or net billing or feed-in mechanism will be entitled to use the power generated. The surplus energy should be injected into the distribution licensee at the interconnection point.

If the generated energy is more than the consumption in a given billing cycle, the surplus energy will be carried over to the next billing cycle for credit and adjustment.

At the end of the settlement period, the net surplus generation will lapse. If the consumption is more than the generation in any given billing cycle, the net consumption units will be charged under retail tariff fixed from time to time.

Net Billing

If the monetary value of the exported energy exceeds the monetary value of the imported energy in any billing cycle, the net credit amount will be carried over to the next billing cycle.

Suppose the monetary value of the exported energy is lesser than that of the imported energy; in that case, the prosumer will pay for the net bill value arrived at in the same month.

Gross Metering

Gross metering will be permitted for eligible consumers who opt to sell all generated solar energy to the distribution licensee instead of availing the net metering or net feed-in facility. The exported solar energy will be credited at the feed-in tariff determined by the Commission. The amount will be credited to the consumer’s electricity bill every billing cycle.

Last November, TNERC passed an order setting a benchmark tariff of ₹2.28 (~$0.031)/kWh to set up 20,000 agricultural solar pumps under Component-C of the KUSUM program.

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