The Grid Controller of India (Grid-India) has proposed extending automatic generation control (AGC) to large-scale renewable energy projects above 100 MW, battery energy storage systems, and pumped-storage projects.

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Primarily used for conventional power sources, AGC can address the intermittency of renewable energy by regulating power generation from renewable energy projects based on demand. By regulating the grid frequency, it can also effectively prevent grid failures due to over-injection of renewables.

According to a consultation paper by Grid India, a pilot project involving a 180 MW large-scale solar project in Rajasthan, integrated with AGC, demonstrated operational feasibility.

SRAS-Down Regulation

The pilot study discovered that large-scale renewable energy projects can operate under AGC with existing infrastructure.

Given the renewables’ struggle with intermittency, the study noted that AGC must be used primarily for secondary reserve ancillary services (SRAS)-down regulation.

While accurate maximum power point tracking (MPPT) greatly improves SRAS-Up benchmarking, estimated MPPT was found sufficient for SRAS-Down.

To improve MPPT data availability, Grid India proposed that all future renewable projects be designed to provide an aggregated MPPT signal at the power plant controller and Supervisory Control and Data Acquisition levels.

It has recommended the provision of an aggregated MPPT signal for all new renewable energy projects under the draft Central Electricity Authority (Construction Standards) 2025.

The pilot study found that zero or very low compensation charges, with no payback to the pool, were the most effective approach for compensating for renewable curtailment.

However, it also proposed that renewable energy project developers receive energy charges at the power purchase agreement tariff during the period of power curtailment. It suggested another framework in which the curtailed project has zero marginal cost but earns a small performance-based incentive for SRAS-Down regulation.

BESS Projects

For evaluating the feasibility of BESS coupling with AGC, a pilot 20 MW/40 MWh lithium-ion standalone BESS was commissioned by a distribution company at Kilokari, New Delhi.

It was observed that the BESS project could ramp up to full output in approximately 300 milliseconds.

The study found that BESS was highly suitable for AGC services, allowing for both SRAS-Up and SRAS-Down.

It also proposed that national load dispatch center-developed state-of-charge/cycle logics may be considered for adoption as a reference for standardization, with scope for battery-technology-specific adaptations.

While AGC calculates performance every 2 to 4 seconds, 1-minute average data was considered ideal for fast-ramping BESS projects. However, a 5-minute data measurement was considered ideal for BESS projects in general.

The study found that AGC integrated with BESS projects should be calculated every 1 minute for the most accurate performance measurement.

It also recommended a zero cooling-off period between charging and discharging operations.

Value stacking, such as combining energy arbitrage with SRAS-Down regulation, significantly improved the viability of BESS projects.

The study also proposed the following two compensation methods for the procurement of reserves from BESS:

Option A- Declared Compensation Charges Plus Incentive

Grid India proposed a settlement for a symmetric energy-charge rate model, with charging energy for SRAS-Down refunded at the compensation charge rate declared by the SRAS provider.

According to this settlement method, the SRAS-Up energy may be paid from the pool at the same rate. However, the round-trip efficiency losses (~15%) may be borne by the BESS project.

It also suggested mileage-based incentives of up to ₹0.5 (~$0.005)/kWh for the power discharged/charged to maintain grid frequency.

Option B- Fixed Charges

Under this method, SRAS-committed BESS reserves may be compensated through the payment of fixed charges.

Pumped Storage Projects

Considering the operational differentiation of PSPs, Grid India suggested adopting PSP-specific AGC modelling and signal architecture.

It proposed that calculating the dispatch availability after excluding the SRAS-Up, SRAS-Down, and the quantum of primary frequency response.

PSPs under AGC should not receive any compensation for energy charges.

It highlighted that PSPs can avail an incentive of up to ₹0.5 (~$0.005)/kWh under CERC (Ancillary Services) Regulations, 2022.

Grid India also proposed that the Commission may consider permitting AGC operation over technically permissible overload bands in pumping mode, to widen the effective regulating range.

The proposal seeks to formally measure and reward the primary frequency response provided by PSPs in both generating and pumping modes by extending the beta factor framework with appropriate sign conventions so that beneficial load changes in pumping mode are correctly recognised. A beta factor framework is a metric for assessing the performance in meeting the primary response obligations.

It suggested providing the same compensation for providing SRAS services as for renewable energy projects.

In a larger bid to encourage SRAS at the intra-state level, Grid India proposed allowing eligible intra-state power projects to participate in the regional SRAS arrangements. Power reserves earmarked by state load dispatch centers under SRAS should be considered towards each state’s compliance with power reserve requirements.

In 2025, the curtailment of wind and solar projects in Rajasthan due to growing grid instability raised grave concerns for the renewable energy sector. Due to curtailments of up to 4 GW in Rajasthan, developers incurred huge financial losses.

In the same year, the grid saw persistent high-frequency above the ceiling on 39 days in the third and fourth quarters of the financial year 2024-25, posing challenges for grid operators and regulators about balancing the injection of solar and thermal power.