Follow CERC’s Deviation Settlement Mechanism Rules: West Bengal Commission to SLDC

State regulator provides interim solution until it aligns regulations with CERC's enacted in 2022

December 13, 2022


The West Bengal Electricity Regulatory Commission (WBERC) has directed the state load dispatch center (SLDC) to follow certain provisions of the Central Electricity Regulatory Commission’s (CERC) deviation settlement mechanism rules, that were enacted this year, until the state Commission notifies its own updated regulations.

The Commission said in its order that it will ensure compliance with both state and central regulations, and that the penalties for deviation are properly reflected in the accounts of intra-state entities.

The order came into effect on December 5, 2022.

As an interim measure for computation of state-level accounts for deviation settlement charges until the amended regulations are issued, the Commission issued the following directives:

  • SLDC must consider a 15-minute time block-wise “normal rate of charges for deviation” determined under the CERC DSM Regulations, 2022, wherever applicable
  • SLDC must consider the “state volume limit” as 100 MW, in line with the limit for higher charges specified for buyers other than the buyer with a schedule less than 400 MW and in renewable-rich states as in the CERC DSM Regulations 2022
  • For imposing an additional penalty of deviation, when the frequency is below 49.85 Hz or above 50.10 Hz, the “normal rate of charges for deviation” of the respective time block will be considered. For this purpose, SLDC must get the block-wise frequency from the Eastern Regional Load Despatch Centre for calculation purposes. Alternatively, SLDC may consider the block-wise supervisory control and data acquisition (SCADA) frequency used for network management for the time being

Additionally, the Commission said that for all other purposes the SLDC must follow the provisions specified in WBERC DSM Regulation 2021.


The Commission enacted the WBERC (Deviation Settlement Mechanism and related matters) Regulations, 2021, to maintain grid discipline by imposing deviation charges to intra-state entities for any changes from their schedule.

The rates for such deviation charges were similar to the CERC DSM Regulations, 2014, to maintain parity between state and central regulations and ensure that penalty for deviation is properly reflected in the accounts of intra-state entities.

However, the central regulator issued CERC DSM Regulations, 2022, by repealing its 2014 regulations. The new regulations brought changes like the following:

  • Delinking frequency from the deviation charge rate
  • The weighted average cost of ancillary service deployed will be the deviation charge rate for each time block
  • The grid entities like drawee and injectors, will have no inkling about the rate, which will be determined post facto

WBERC noted that to facilitate integrated grid management, it is required to maintain parity between the state and central regulations.

The state Commission observed that the changes brought by the CERC need detailed analysis and impact assessment, given state-specific conditions, before adopting the principles through an amendment to WBERC DSM Regulations, 2021.

Under these circumstances, the state load despatch center (SLDC) apprehended certain difficulties in implementing the WBERC DSM Regulations 2021, which is linked with the CERC DSM Regulations 2014. The SLDC sought necessary guidelines for proper implementation and smooth transition of state-level accounts for deviation settlement charges

Considering the interlinks between WBERC DSM Regulations, 2021 and CERC DSM Regulations, 2014, the West Bengal regulator felt it is necessary to address those issues to avoid complications post-repeal of the CERC DSM Regulations 2014.

Various wind and solar energy project developers Mercom spoke to had raised concerns about being charged a penalty for under-injection but granted no compensation for over-injection of power.

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