The Central Electricity Regulatory Commission (CERC) has approved a detailed procedure for maintaining minimum generation levels (Minimum Turndown Level or MTL) at section 62 generators through the Security Constrained Economic Despatch (SCED) mechanism. This order was issued on March 12, 2025. The approved procedure will be effective from March 24, 2025.
It may be recalled that the CERC had notified the Indian Electricity Grid Code (IEGC) Regulations, 2023, effective from October 1, 2023.
A subsequent amendment in 2024 mandated the National Load Despatch Centre (NLDC) to submit a detailed procedure for moderating schedules up to the MTL for Section 62 generators (those with tariffs determined by CERC) through SCED.
NLDC, after stakeholder consultation, submitted the procedure for approval, which CERC has now granted.
Key Provisions of the Approved Procedure
The procedure applies to all regional entity thermal generating stations with tariffs determined under Section 62 of the Electricity Act, 2003 (“Eligible Generating Stations”). These stations must participate in both SCED-Up and SCED-Down.
Stations under Security Constrained Unit Commitment (SCUC) or those operating in Two-Shift mode during off-bar periods are excluded. Gas based generating stations that are selected under SCUC or that are brought on bar for meeting peak demand or reserve requirements are excluded.
Role of Eligible Generating Stations
Stations must coordinate with Regional Load Despatch Centres (RLDCs) for scheduling. They must review their injection schedules and report any schedules below MTL during off-peak hours to NLDC.
Stations must provide declarations to RLDCs and NLDC regarding their efforts to sell power in the market to achieve MTL. Failure to provide these declarations in a timely fashion will result in the stations being barred from MTL support through SCED for a period of five days.
Role of NLDC
NLDC will prepare a list of stations likely to go below MTL. This list will be published on the NLDC website.
NLDC may exclude stations from the list due to anticipated congestion on inter-regional corridors. NLDC will publish the final list of stations eligible for MTL support through SCED.
NLDC will prioritize SCED down in exporting regions, and SCED up in importing regions, during times of congestion.
This procedure is significant because it:
- Provides a structured approach to maintaining minimum generation levels at thermal power plants.
- Enhances grid stability by preventing sudden drops in generation.
- Promotes efficient power management through the SCED mechanism.
- Ensures transparency through the publication of eligible generating stations.
