For decades, India’s coal power stations ran steadily, quietly carrying the country’s electricity load. Now, as solar and wind flood the grid and force thermal plants to ramp up and down like never before, those same stations are being pushed into operating conditions they were never designed for.
Yet a high-level technical committee has found that the rising breakdowns across the thermal fleet are not being caused by flexible operations to absorb renewables, but by ageing equipment, poor operating practices, and long-standing maintenance gaps.
The Central Electricity Authority (CEA)-led committee on wear and tear of thermal units—constituted after mounting concerns from generators over rising failures—found no significant evidence that low-load, flexible operation at around 55% of capacity has directly resulted in major equipment damage.
Bulk of failures were linked to old infrastructure
Instead, the bulk of failures were linked to old infrastructure, procedural lapses, coal quality issues, and delayed maintenance accumulated over decades of baseload operation.
“Failures should not be attributed exclusively to flexible operation,” equipment manufacturer Bharat Heavy Electricals (BHEL) told the committee, noting that several plant components were already operating close to fatigue limits even before renewable integration intensified. With appropriate control system upgrades and retrofits, BHEL said thermal units can safely operate at lower loads without compromising reliability.
The findings challenge claims from major generators
The findings challenge claims from major generators who had blamed frequent ramping for accelerating equipment stress. NTPC Limited had reported 692 boiler tube leakages between FY22 and September 2025, warning that repeated cycling was causing thermal fatigue. However, the committee’s detailed technical assessments of individual units presented a different picture.
Case studies of the 39-year-old Farakka Super Thermal Power Station Unit-2 and the newer Jhajjar Power Station Unit-3 showed that outages were overwhelmingly driven by electrical faults, ageing piping, boiler fouling, coal quality, and operational disturbances—rather than sustained low-load operation.
Even with conservative ramp rates of around 0.5% per minute, failures continued, indicating systemic weaknesses rather than flexibility-induced stress.
The report further noted that global experience shows the highest thermal stress occurs during start-ups, shutdowns, and sudden tripping events, when temperature and pressure fluctuations are extreme—not during steady reduced-load running.
At the same time, the committee acknowledged that renewable energy is fundamentally reshaping grid operations. Grid operators told the panel that during high solar generation periods, thermal plants are being backed down close to minimum technical limits while renewable output is sometimes curtailed to maintain frequency stability. On one peak day in May 2025, nearly 10 GW of solar power was curtailed even after coal generation was reduced to around 58%, with grid frequency touching 50.48 Hz.
“The system is being pushed harder every month,” a senior grid official told the committee, adding that flexibility has become essential for maintaining grid security.
With India targeting 500 GW of non-fossil capacity by 2030, the committee warned that operational swings will intensify sharply. Without flexible thermal plants—alongside storage and transmission upgrades—renewable curtailment and reliability risks will increase.
However, it cautioned that regulatory mandates alone will not ensure safe flexibility. “Merely meeting minimum load thresholds without technical solutions will result in premature equipment failures,” BHEL said, calling for advanced control systems, digital monitoring, component retrofits, and predictive maintenance across the thermal fleet.
The report also flagged slow progress on pilot projects such as two-shift operations meant to assess deeper flexibility impacts, noting reluctance from major generators despite regulatory directions.
Power sector officials told the panel that without rapid modernisation of the thermal fleet, system bottlenecks could undermine the clean energy transition. “The danger is we build massive renewable capacity but lack the system flexibility to absorb it,” one official said.
The committee’s conclusion is blunt: renewable energy is not destroying India’s coal plants—it is exposing structural weaknesses long masked by steady baseload operations.
For decades, thermal stations were designed for constant output, with maintenance and operating practices built around stability. The new grid demands rapid response, precision control, and far more sophisticated asset management.
What is required now, the panel said, is a shift from reactive repairs to predictive maintenance, from manual systems to digital controls, and from ad-hoc ramping to scientifically managed flexibility.
“You cannot run tomorrow’s power system with yesterday’s engineering,” one senior official involved in the review said.
As India accelerates toward a renewable-heavy grid, the report underlines a crucial reality: modernising the coal fleet is not a barrier to the clean energy transition but a prerequisite for making it reliable, affordable, and sustainable.