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New Regulations in Tamil Nadu for Wind and Solar Energy.

The Tamil Nadu Electricity Regulatory Commission (TNERC) has issued regulations for forecasting, scheduling, and deviation settlement for wind and solar energy generators in the state. Titled the "Tamil Nadu Electricity Regulatory Commission (Forecasting, Scheduling and Deviation Settlement and related matters for Wind and Solar Generation) Regulations, 2024," these rules came into force on 01-04-2024. The objective is to facilitate grid integration of wind and solar energy while ensuring grid stability and security. The regulations define key terms, outline the extent of applicability, and establish a framework for managing deviations and settlements among various stakeholders.

 

TNERC regulations mandate forecasting, scheduling, and deviation settlement for Wind and Solar Energy Generators in Tamil Nadu. SLDC considers forecasts for operational planning, utilizing conventional units and tie-lines for integration. Applicable to all generators connected to the intra-state system. QCAs appointed for forecasting and scheduling activities. SLDC issues notices for QCA appointments; failure results in deviation charges. Responsibilities of QCA include aggregation, de-pooling, and real-time data provision. The code specifies methodologies for scheduling and deviation treatment. SLDC may also forecast Wind and Solar energy generation. The regulations will be reviewed by the Commission every two years.

 

Summary:

 

The regulations delineate guidelines for forecasting, scheduling, and deviation settlement for Wind and Solar Energy Generators in Tamil Nadu. Notable points include:

 

Forecasting and Scheduling Code:

  - Detailed schedules for Day-Ahead and Week-Ahead.

  - Revisions permitted with prior notice.

  - SLDC to present Detailed Procedure for approval.

  - Guidelines for adherence, penalties for manipulation, and QCA roles.

 

Principles of QCA Appointment:

  - Generators designate QCAs for scheduling, with choices for a single QCA for the state or specific sub-stations.

  - SLDC's forecast option is available.

 

Deviation Settlement for Intra and Inter-State Transactions:

  - Deviation charges for under/over injection of wind/solar power.

  - Distinct settlements for intra and inter-state transactions.

  - SLDC calculates and discloses monthly deviation statements for scrutiny and payment.

 

QCA Aggregation and Communication:

  - Single QCA aggregates wind/solar generation for the entire state, providing separate schedules for each to SLDC.

  - Pooling sub-station-wise schedules shared with SLDC.

 

Alternative Aggregation:

  - If aggregating for the entire state is challenging, QCA can submit schedules for individual pooling stations.

  - Deviation charges calculated separately for each pooling sub-station.

 

Schedule Reference and Charges:

  - QCA supplies SLDC with a schedule based on its forecast, acting as a reference for deviation determination.

  - If QCA adopts SLDC's forecast, it bears consequences of any resulting deviations.

  - Charges for QCA services agreed upon mutually between QCA and generators.

 

Forecast Submission:

  - QCA provides Day-Ahead and Week-Ahead schedules for SLDC, considering statewide aggregation.

  - Internally maintains schedules for each pooling sub-station.

 

Regulation Details and Compliance:

  - Detailed procedure to be submitted by SLDC covering various aspects (registration, communication, compliance, penalties).

  - Commercial impact of deviations borne by generators.

  - State entities adhere to Indian Electricity Grid Code and Tamil Nadu Electricity Grid Code.

  - Strict measures against gaming, intentional mis-declaration, and penalties.

 

Principles of QCA Appointment:

  - Generators appoint QCA for the whole state, specific sub-stations, or opt for SLDC's forecast.

  - Majority-appointed QCA deemed for all generators in a pooling sub-station.

  - Appointment within one month of SLDC intimation, failure subject to stipulated conditions.

 

Deviation Settlement:

  - Intra-state transactions settled based on actual generation; provisional charges applied monthly.

  - Different deviation charges for wind and solar.

  - De-pooling undertaken by QCA against each generator.

  - SLDC oversees monthly settlement; deviations due to forced shutdown exempted under specific conditions.

  - Inter-state transactions follow CERC regulations with separate schedules and settlements.

 

Deviation Accounting:

  - Separate accounting for inter and intra-state deviations.

  - SLDC computes and bills monthly intra-state deviations; inter-state transactions detailed on SLDC website.

  - QCA/generators make payments to the state deviation pool account.

 

Meter Replacement:

  - Licensee to replace defective meter within 30 days; charges adjusted in generator's monthly bill.

 

- Generation Readings and Deviation Reporting (10.3-10.5):

  - SLDC provides monthly 15-minute block generation readings to QCA.

  - QCA consolidates SLDC readings, compares with scheduled generation, and reports monthly deviations.

  - Deviation charges calculated by SLDC based on scheduled and actual generation.

 

Hybrid System Metering:

  - Hybrid system (wind/solar) requires separate metering; deviations treated independently.

  - Metering follows Central Electricity Authority Regulations.

 

QCA-SLDC Communication:

  - Detailed Procedure outlines QCA-SLDC communication protocols.

  - SLDC equipped with IT-enabled platform; QCA provides login for live data access.

  - Communication covers schedules, deviations, grid constraints, and more.

 

Deviation Accounting Methodology:

  - SLDC computes Absolute Error for statewide, pooling sub-station, and generator-wise deviations.

  - Deviation charges impact on Wind and Solar Energy maintained separately in State Deviation Pool Account.

 

Payment Mechanism and Security:

  - Generators pay monthly deviation charges based on actual generation.

  - Provisional payments through Distribution Licensee; delay incurs 0.06% daily interest.

  - Year-end reconciliation adjusts excess or shortfall without interest.

  - Delayed payment beyond 12 days may utilize State Deviation Pool Account balance.

 

De-Pooling of Deviation Charges:

  - QCA de-pools deviation charges against each generator in proportion to actual generation.

 

Curtailment Intimation:

  - SLDC communicates curtailment in emergent situations; no deviation charges.

  - QCA notifies generators for planned curtailment; SLDC revises schedule if not amended.

 

Energy Accounting:

  - Energy accounting based on interface meters; monthly accounts prepared by QCA.

  - SLDC provides processed data monthly; discrepancies corrected within 15 days.

  - Billing center handles energy accounting, adjustments, and settlement as per SLDC procedure.

 

Miscellaneous Provisions:

  - Commission empowered to amend regulations, relax provisions, and issue directions.

  - State Power Committee established for coordination, compliance monitoring, and regulatory guidance.

  - Repeal and savings clause for previous regulations.

  - Provision for resolving difficulties and power to relax regulations.

  - Commission authorized to issue orders and directions for regulation implementation.

 

Explanatory Statement (Explanatory Statement):

  - Explanation of the need for the new regulations, referencing previous regulations and changes in Central Commission regulations.

 

 

The new regulations, Tamil Nadu Electricity Regulatory Commission (Forecasting, Scheduling, and Deviation Settlement for Wind and Solar Generation) Regulations, 2024, replace the previous ones from 2019. The key changes include:

 

Deviation Charges Calculation:

  - Formula for deviation charges adjusted; now based on the highest of weighted average Area Clearing Price (ACP) from various market segments for a given time block.

 

Error Percentage Definition:

  - Error percentage calculation modified for better realism.

  - Absolute error percentage now based on "Scheduled Generation" instead of "Available Capacity" to ensure accurate deviation assessment.

  - Central Electricity Authority suggests considering "Available Capacity" but Commission caps deviation charges at a minimum to protect Renewable Energy (RE) generators.

 

Technological Advancements:

  - Improved forecasting technology for wind/solar energy since the introduction of previous regulations in 2014.

  - Developers are expected to be more accurate in forecasting.

 

Purpose of Deviation Settlement Mechanism:

  - Emphasis on the mechanism's purpose: accuracy in forecasting RE power to enhance grid management.

  - Aims to instill discipline among RE generators for better load management and grid frequency adherence.

 

Protection of RE Generators' Interests:

  - No deviation charges for forced curtailment instructed by SLDC.

  - Separate "detailed procedure for management of RE curtailment" to be issued to safeguard solar/wind generator interests.

 

Absolute Error Percentage Formula Endorsement:

  - Commission supports the formula for Absolute Error Percentage in the interest of all stakeholders.

 

Single QCA Selection:

  - Proposes a single QCA selection for statewide aggregation to simplify implementation.

  - Maintains the option for solar/wind generators to choose QCA at the Pooling Sub-Station level based on majority principles.

 

Regulation Framing and Ceiling Rates:

  - New regulations framed to accommodate changes in technical, commercial, and implementation mechanisms.

  - Ceiling rates for wind and solar energy deviation refixed based on a pilot study conducted by the SLDC.

 

Repeal of Previous Regulations:

  - The new regulations repeal the existing ones from 2019.

 

Conclusion:

The regulations aim to enhance the accuracy of forecasting for RE power, ensure fairness to generators, and simplify implementation through single QCA selection. The changes reflect advancements in technology and a commitment to optimal grid management.


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