Tamil Nadu State Load Dispatch Centre (TNSLDC) and Tamil Nadu Electricity Regulatory (TNERC) have issued the procedure for forecasting, scheduling, and deviation settlement mechanism of wind and solar generation.

The procedure aims to establish guidelines to help maintain grid discipline and grid security under the grid code through the commercial mechanism for deviation settlement through drawl and injection of electricity by the users of the grid.

It will apply to all wind, and solar energy generators (excluding rooftop photovoltaic solar power projects) in Tamil Nadu 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.

The regulations also mandate that a qualified coordinating agency (QCA) be appointed for meter reading, data collection, and communication. The QCA would also ensure coordination with the distribution companies (DISCOMs), the state load despatch centers (SLDCs) and other agencies, as well as oversee the settlement of deviation charges.

According to the procedure, forecasting of wind or solar power injection on a pooling sub-station basis will be done by the TNSLDC for the overall planning of resource requirements on the day ahead basis given the secure grid operation. The QCA will also be responsible for providing pooling sub-station wise forecasts for wind or solar generators connected to pooling sub-station to TNSLDC.

The document also lays down the procedure for energy accounting, deviation accounting, and the methodology used for setting deviation charges. Also, it lists guidelines to be followed for payment mechanism of deviation charges, monitoring of compliance, and grievance redressal.

In March 2019, the Maharashtra Electricity Regulatory Commission (MERC) exempted renewable energy qualified coordinating agencies for meter reading, data collection, and communication from paying scheduling and forecasting charges.

In May 2019, the Central Electricity Regulatory Commission (CERC) finalized the fifth amendment to its deviation settlement mechanism regulations.