Tamil Nadu announces (Forecasting, Scheduling and Deviation settlement and Related Matters for Wind and Solar Generation) Regulations, 2019

Executive summary:

• The accuracy band is narrower compared to other states and compared to the Model FOR Regulations
• However, the per unit DSM charge is also lower compared to other regulations (in these aspects TN regulation is similar to that of Gujarat)
• Total DSM charge is capped at Rs 0.05/unit on an annual basis
• Aggregation is not allowed

Applicability:

• From the date of publication in the official gazette.
• Forecasting tool to be established in three months period.
• Levy and collection of DSM Charges shall commence after six months from the date of publication in the official gazette.

Regulation Applicable on all Wind and Solar Energy Generators (excluding Rooftop PV Solar power projects) in Tamil Nadu
Deviation Accounting:  The deviation accounting will be carried out based on the Available Capacity:-                                                                            
Generation =  Absolute Error in % = 100 X Actual Generation –  Scheduled/ Available Capacity (AvC)
Point of Forecasting: Plants connected to the Intra-State Transmission System or Distribution System, including those connected through Pooling sub-stations, and using the power generated for self-consumption or sale within or outside the State.
Aggregation: Unlike in Karnataka and AP, Tamil Nadu’s regulation does not have a provision to provide an aggregated forecast.
Role of a QCA:

• Meter reading and data collection and its communication, and coordination with the Distribution Licensees, the SLDC and other agencies;
• De-pooling of Deviation Charges within the constituent Generators of the Pooling sub-station and settlement of payments/receivables.
• Settlement of the Deviation Charges specified in these Regulations with the SLDC on behalf of the Generators.

Revisions:

• The QCA may revise the Schedule of Generators connected to the Intra-State Transmission Network (excluding collective transactions) by giving advance notice to the SLDC.
• 16 revisions are permitted for Generators starting from 00.00 Hrs of the All the revisions are effective from the 4th time-block.

Other Key Points:

• The total deviation charges remitted on account of deviations by a wind / solar generators through QCA into State Deviation Pool Account (Wind and Solar) in a financial year shall be capped at the Ceiling Rate of 5 paise per unit, and excess DSM charges beyond this limit shall be remitted back to the generator.

• Every QCA shall pay the total amount of Deviation Charges pertaining to the Pooling Sub-station to the SLDC, and collect it from the concerned Generators in proportion to their actual generation.

• Provided that the onus of ensuring the payment of the Deviation Charges to the SLDC by the QCA shall remain that of the concerned Generators.

• The QCA shall de-pool the Deviation Charges against each Generator in proportion to the actual generation by the generators.

• The SLDC will share the curtailment information with the QCA id any, via an IT-enabled communication system; failing which the DSM for subsequent time blocks will not be charged by the SLDC.

• Further, it is the QCAs responsibility to provide the correct schedule on the basis of curtailment.

• If the QCA is unable to do so, the SLDC will change the schedule as per the curtailed values.

Important differences between intrastate and interstate transactions:

• The deviations for Inter-State and Intra-State transactions at Pooling Station will be accounted for separately. Separate schedules will be sent for the interstate to SLDC and RLDC.
• The Inter-State transactions will be settled on the basis of their scheduled generation and will be considered only if the Inter-state capacity is connected to the STU via the separate feeder.
• The Generator will pay the Deviation Charges for under or over injection applicable within Telangana in case of deviations in the State DSM Pool.

Deviation Charges in case of under or over-injection for sale/supply of power within the State

Deviation Charges in case of under or over-injection for sale/supply of power outside the State

• Deviations in respect of Inter-State and Intra-State transactions for each source of RE i.e. wind and solar Generation shall be accounted for separately at each Pooling Sub-Station.
• The SLDC shall provide separate energy and Deviation Accounts for Inter-State and Intra-State transactions in respect of wind and solar Generation to the QCA, who shall settle the Deviation Charges with the concerned Generators.

The TNERC Regulation for Forecasting & Scheduling, 2019 has not provided a summary of timelines designating the activities to QCA and SLDC, to be accomplished within the following stipulated duration.