CERC order sets deviation settlement value for wind and solar from April 2026

The Central Electricity Regulatory Commission (CERC) has issued an order dated March 31, 2026, determining the deviation settlement value for wind and solar power sellers.

The new valuation framework becomes effective from April 1, 2026.

Regulatory Frameworks

The Central Electricity Regulatory Commission (CERC) establishes the principal framework for renewable energy projects connected to India’s interstate transmission system. Under this structure, the National Load Dispatch Centre (NLDC), Regional Load Dispatch Centres (RLDCs), and other system operators issue the specific procedures governing these interstate projects. In contrast, projects connected within a single state fall under the jurisdiction of the respective State Electricity Regulatory Commission (SERC), the State Load Dispatch Centre (SLDC), and the state grid code.

For instance, Karnataka, Tamil Nadu, Rajasthan, Gujarat, and Andhra Pradesh currently maintain non-interchangeable regulatory requirements.

It remains unknown whether India’s different state frameworks will eventually converge into a more unified system.

Scheduling and Data Requirements

• Utility-scale wind and solar projects must submit a day-ahead schedule divided into 15-minute time blocks.
• A complete 24-hour schedule comprises 96 distinct intervals.
• The seller, generator, or Qualified Coordinating Agency is responsible for submitting this day-ahead schedule.
• Regulatory procedures define specific submission cut-offs, minimum lead times, and the permitted number of intraday revisions.
• Participants must also provide week-ahead forecasts to support outage planning, transmission coordination, or portfolio management.
• Load-dispatch centers require continuous telemetry data covering active power, voltage, frequency, and plant status.

Settlement Mechanics and Enforcement

The financial settlement process relies on comparing the scheduled energy injection against the actual energy delivered within each settlement block. When a wind or solar generator’s real-time output diverges from its submitted day-ahead schedule, the system calculates the difference to determine the applicable charges or credits.

To support these calculations, the Central Electricity Authority published guidelines for automatic weather stations in July 2025. These stations provide the data necessary for nowcasting, which covers short-term horizons ranging from a few minutes to approximately 30 minutes ahead.

Participants who fail to adhere to scheduling or data requirements may face formal notices from system operators. Depending on the severity and frequency of the non-compliance, affected projects could also be subject to contractual remedies or broader regulatory action.

Nowcasting, Floating Solar, and Data Integrity

All-sky imagers monitor cloud movement over the facility to gauge shifts in irradiance and power generation for the shortest prediction windows. This "nowcasting" function, covering periods from a few minutes up to approximately 30 minutes ahead, aids intraday adjustments and operator vigilance in areas where fast-forming clouds cause sharp output swings. Although this immediate-term layer supplements rather than supplants the day-ahead plan, it refines balancing choices. Floating solar systems require models that incorporate reservoir-based humidity, wind exposure, haze, water-surface temperature, and variable access to meteorological gear.

Prediction accuracy depends on data quality and representativeness, necessitating plant-level SCADA, irradiance sensors, automatic weather stations, outage logs, and curtailment directives. Precise time synchronization is essential, because discrepancies between forecast intervals and settlement meters can produce apparent errors despite accurate meteorological predictions. Data transfer must satisfy cybersecurity and interface standards, typically engaging the EPC contractor, SCADA provider, Qualified Coordinating Agency, plant operator, utility, and grid control center.

In July 2025, the Central Electricity Authority released guidelines for automatic weather stations at solar and wind facilities. While this guidance pertains to the measurement infrastructure underpinning forecasts, each project must still confirm requirements set by its SLDC, RLDC, connectivity contract, or tender specifications. Providers must separate forecasts from telemetry; forecasts outline future injection, whereas SCADA, meters, and weather stations reflect current plant status. A system built for an ISTS project might fail to satisfy the data format, timing, or aggregation needs of an SLDC-linked plant, especially when applicable PPAs, open-access deals, or market-participation contracts impose additional duties.