Coal fleet’s changing role in the power system

The report analyzes the evolving role of India's coal-fired power fleet as variable renewable energy (VRE) expands. It projects a structural shift from steady baseload generation to flexible balancing resources by FY 2031–32, characterized by deeper midday turndowns and steeper ramping requirements to accommodate solar peaks. This transition is expected to lower overall plant load factors (PLF) and disproportionately impact higher-cost, less efficient units.

• India's coal fleet is transitioning from a baseload role to providing flexible balancing resources to integrate variable renewables. This requires units to operate closer to their Minimum Thermal Load (MTL) during the day and ramp up quickly for evening peaks to avoid curtailing renewables or relying on expensive gas-based generation.
• The 2023 Grid Code formalizes the Minimum Thermal Load (MTL) at 55% of rated capacity, with ramping expectations of approximately 1% of rated capacity per minute. However, modelling for FY 2031–32 suggests that to maintain system stability and minimize gas use, many plants may need an effective MTL of around 40%.
• In 2025, the coal fleet demonstrated significant flexibility due to rapid solar expansion and slower demand growth. For example, in April 2025, coal generation declined by 52 GW between 07:00 and 13:00, averaging a ramp-down of 8.7 GW/hour.
• By FY 2031–32, the daily swing in coal output is projected to reach approximately 78 GW, with peaks at 190 GW during non-solar hours and troughs of 112 GW at midday. The morning ramp-down is expected to be steeper than in 2025, falling 78 GW in three hours (approximately 433 MW/min).
• The burden of flexibility currently falls disproportionately on a few centrally dispatched Inter-State Generating Station (ISGS) plants, while intra-state generators remain largely unresponsive. This imbalance has led to forced outages or over-injection into the grid to maintain operations above the MTL.
• Overall coal utilization is projected to decline from a plant load factor (PLF) of approximately 69% in FY 2024–25 to 55% by FY 2031–32. This decline will be non-uniform, with plants having variable costs higher than roughly INR 2.8/kWh seeing the sharpest reductions in run-hours.
• The report concludes that India will not require new coal capacity beyond the 35 GW currently under construction to maintain supply-side security through FY 2031–32, as approximately one-third of existing capacity will see a sharp decline in utilization, with some units becoming completely idle.

APA

Ember (2025). Coal fleet’s changing role in the power system. https://ember-energy.org/chapter/coal-fleets-changing-role-in-the-power-system/

Chicago

Ember. Coal fleet’s changing role in the power system. 2025. https://ember-energy.org/chapter/coal-fleets-changing-role-in-the-power-system/.

Wikipedia

{{cite report |author=Ember |title=Coal fleet’s changing role in the power system |date=29 October 2025 |url=https://ember-energy.org/chapter/coal-fleets-changing-role-in-the-power-system/ |access-date=17 August 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{ember2025coal, author = {{Ember}}, title = {{Coal fleet’s changing role in the power system}}, institution = {Ember}, year = {2025}, month = oct, url = {https://ember-energy.org/chapter/coal-fleets-changing-role-in-the-power-system/}, urldate = {2026-08-17}, note = {Indexed by Climate Insights Directory} }