Tamil Nadu Electricity Regulatory Commission’s (TNERC) generic tariff order for grid-connected solar energy generating system (rooftop systems) of various capacities, has evoked a mixed response.
The tariff order came into effect from October 22 and is applicable till March 31, 2023. Tamil Nadu’s solar energy policy 2019 has stated a target of achieving 3600 MW of solar energy in the consumer category by 2023, but only about 325 MW or 9.03% has been achieved, TNERC said.
It fixed a tariff in the range of ₹3.10-₹3.61per unit for capacities in the range of 10 kW to 999 kW. A 20% higher tariff has been fixed under the category called time-of-day (ToD) tariff to encourage consumers to install energy storage facilities. Under this, the tariff ranges from ₹3.72-₹4.33 per unit.
TNERC said all domestic consumers are eligible for net metering mechanism, except those living in huts and agriculture consumers. Also, they have additional option of choosing the net feed-in mechanism. In the net metering mechanism, the energy supplied to the grid from the rooftop solar system is deducted from the energy consumed for own use and the resulting net units are billed based on the applicable retail tariff.
In the net-billing or net feed-in mechanism, the energy supplied to the grid is based on feed-in tariff and the energy consumed is billed at applicable retail tariff. The gross metering mechanism involves direct sale of the units produced by the solar system to the grid and is accounted for at feed-in tariff.
Domestic consumers who have provided net-feed-in facility under the 2019 order, shall have the option to migrate to the new net metering system, while LT consumers are not eligible for gross metering, as per the order.
The order provides a boon to domestic solar users with net metering, which is not allowed at present and will certainly push the solar enthusiasts to choose the solar option in a big way, K.E.Raghunathan, who has spent 36 years in solar space and also currently in the Advisory Committee of TNERC representing MSME, said.
Martin Scherfler, a renewable energy expert and co-founder of Auroville Consulting pointed out that introduction of network charges (₹0.83 per unit and ₹1.27 per unit for HT and LT consumers respectively) will be a dampener and it is unlikely that Tamil Nadu will be able to meet its rooftop solar target of 3,600 MW by 2023.
Assuming that the network charges will increase every year by at least 5% (rate of inflation), the network charges at the end of 25 (lifetime of the solar) for LT consumers will be ₹4.30 per unit and for HT consumers, it will be ₹2.81 per unit. At this rate the network charges will be higher than the cost of solar generation, resulting in defacto net negative returns to the consumers, he added.
