India’s coal buffer falls to 10 days as 45 power stations reach critical levels

India’s power system is facing a tightening coal-supply buffer after the number of generating stations with critically low inventories jumped to 45, from 31 at the end of July, as heavy rainfall disrupts mining and fuel transportation across major coal-producing states.

Central Electricity Authority data as of August 25 showed that 40 of the affected stations depend primarily on domestic coal. Total inventories at power plants had fallen by approximately 19% since the end of July to 30.95 million tonnes, equivalent to about 10 days of operational requirements compared with roughly 12 days a month earlier.

The situation has not yet translated into evidence of a nationwide electricity shortage, but the shrinking inventory buffer is forcing operational changes. The power ministry has asked some coal-fired plants to postpone scheduled maintenance until the supply picture becomes clearer, while an NTPC official told Reuters that some stations requiring five or six coal rakes were receiving roughly half that number.

Why have coal inventories fallen so sharply at Indian power plants during August?

The immediate problem is an unusual combination of too much rain where coal is mined and insufficient rainfall across much of the country where electricity is consumed. Heavy downpours in Odisha, Jharkhand and Chhattisgarh have disrupted open-cast mining operations and slowed the movement of coal from mines to power stations, placing pressure on the railway-dependent logistics chain that supports thermal generation.

India has simultaneously received around 12% less rainfall than normal during the current monsoon season, with the developing El Niño contributing to uneven rainfall and hotter conditions in several regions. Air-conditioning demand has consequently remained elevated, particularly during the evening and nighttime hours when solar generation falls away and coal-fired plants carry a larger share of the electricity requirement.

Those two pressures reinforce each other because generators are burning more coal precisely when replacement supplies are moving more slowly. A plant can therefore deteriorate from a comfortable inventory position to a critical category surprisingly quickly when several days of strong generation coincide with reduced rake deliveries.

India has experienced similar seasonal coal-management pressures during previous monsoons, but the increase from 31 to 45 critical plants within less than a month shows that the present deterioration is occurring quickly enough to require active intervention.

What does the government mean when a power plant has a critical coal stock?

A critical classification does not mean the plant has already run out of fuel or stopped generating electricity. Central Electricity Authority monitoring compares actual inventories with the normative stock each generating station is expected to maintain, and plants falling sharply below those requirements enter increasingly serious categories that signal reduced resilience to further supply interruptions.

The latest reporting identifies plants holding less than 25% of required inventories, with some having coal sufficient for fewer than three days of generation. That makes the geographical distribution of fuel particularly important because the national figure of 30.95 million tonnes can appear comfortable while individual stations face much tighter conditions.

A station close to a mine with assured rail capacity can operate safely with a smaller on-site stock than a distant plant vulnerable to transport disruption, which is one reason authorities monitor both tonnes and operational days. The present concern is therefore not that India possesses only 10 days of coal in an absolute sense, but that the system’s inventory cushion has narrowed while a significant number of individual generators are already operating close to their minimum comfort levels.

That distinction also explains why the ministry can respond through logistics and operating decisions before resorting to emergency electricity measures. Additional rakes, priority coal allocation and postponement of maintenance can stabilise individual plants if mining and transportation recover quickly.

Why has the power ministry asked some generating units to delay maintenance?

Thermal generating units normally undergo scheduled maintenance during periods when system operators believe enough alternative capacity is available. Taking a unit offline can also temporarily reduce the amount of coal being consumed at that particular station, but widespread maintenance during a period of elevated electricity demand can reduce the grid’s ability to compensate if another generator suddenly faces a fuel or technical problem.

The ministry’s request to delay some planned outages therefore reflects the need to maximise available generating capacity while the coal supply chain remains uncertain. Keeping more units technically available gives grid operators additional flexibility to redistribute generation among plants depending on where fuel remains adequate.

This does not mean every coal unit will be forced to operate continuously regardless of technical requirements. Essential maintenance cannot simply be ignored without creating another reliability risk, and plant operators must balance fuel availability against equipment condition and statutory safety requirements.

The direction instead demonstrates how narrowing coal inventories can affect power-system planning before consumers experience visible disruption. Maintenance scheduling, railway movements and generator dispatch increasingly become part of the same coordinated response.

Could the coal shortage lead to electricity cuts across India?

The current data support concern about reduced operating margins rather than a conclusion that large-scale blackouts are imminent. India has a diversified national generating system, and individual coal shortages can be managed through generation transfers, additional hydroelectric output where water is available, renewable generation, gas-based power and increased coal deliveries to the most vulnerable stations.

The more serious scenario would involve critical stocks continuing to rise while electricity demand remains high and mining or rail transport suffers further disruption. Under those conditions, generators could be forced to reduce output because they need to conserve limited fuel, increasing the pressure on grid operators during peak-demand hours.

Coal remains particularly important because installed renewable capacity and actual round-the-clock generation are different measures. Solar contributes strongly during daylight hours, but evening cooling demand must be supplied by coal, hydro, storage, gas or other dispatchable sources once the sun sets.

India therefore has time to restore the fuel buffer, but less room for another significant disruption than it had a month ago. The movement from 31 critical plants to 45 matters precisely because electricity systems become vulnerable when several individually manageable problems begin occurring simultaneously.

What should be watched as India moves towards the end of the monsoon?

Coal rake deliveries will provide one of the earliest indications of whether pressure is easing. If mining conditions improve and rail movements normalise across Odisha, Jharkhand and Chhattisgarh, inventories can recover relatively quickly because India’s domestic coal industry operates at enormous scale.

Electricity demand will be equally important. More widespread rainfall and cooler temperatures would reduce air-conditioning loads, allowing plants to rebuild stocks even without a dramatic increase in daily coal deliveries.

The less favourable outcome would combine continued weak rainfall across demand centres with further heavy precipitation in mining regions. That mismatch would keep coal consumption elevated while preventing supply from catching up, potentially pushing additional stations into critical categories.

India is not yet confronting a national power crisis, but the inventory trend has moved sufficiently far to make complacency risky. Coal stocks have lost roughly one-fifth of their buffer in less than a month, and the next several weeks will determine whether that represents a temporary monsoon disruption or the beginning of a more difficult electricity-supply season.