GS Paper III | Energy Security | Infrastructure | Renewable Energy | Climate Change
Current Affairs | 11 September 2026
India’s Coal Stock Stress: What It Reveals About the Power-Sector Transition
Introduction
Nearly one-third of India's monitored coal-fired power plants are facing critically low fuel stocks at a time when electricity demand remains close to record levels.
According to Central Electricity Authority data reported on 11 September 2026, the number of plants with critically low coal inventories rose to 59 as of 9 September, compared with 45 at the end of August. Electricity demand has recently remained around 267 GW, close to the record peak of 270.70 GW reached in May 2026.
The situation may appear surprising because India has simultaneously crossed 300 GW of non-fossil electricity capacity.
However, the apparent contradiction highlights one of the central challenges of India's energy transition:
Adding renewable capacity is not the same as guaranteeing reliable electricity at every hour of the day.
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What is causing the present coal-stock stress?
Several factors have come together.
Prolonged hot weather has kept electricity demand unusually high, particularly because of increased cooling requirements.
At the same time, lower hydro availability and inadequate large-scale electricity storage have increased the burden on coal-based power plants when solar generation is unavailable.
As of 9 September, 59 coal plants had stocks below the critical threshold—either less than around one-fourth of the required inventory or sufficient for only a few days of generation.
The government has responded by accelerating fuel movement.
On 6 September, 444 coal rakes were reportedly deployed for power-sector supplies, compared with 370 on 3 September. Coal India has also increased road transport and reported roughly 76 million tonnes of coal available at its mine pitheads.
This indicates an important distinction:
India may possess adequate coal at mines while individual power stations can still experience shortages because of transport, logistics and inventory-management constraints.
Why does India still depend heavily on coal?
India has made rapid progress in clean-energy capacity.
As of 31 July 2026, total non-fossil installed electricity capacity reached 300.50 GW, comprising:
- Solar: 164.59 GW
- Wind: 58.14 GW
- Hydro: 57.24 GW
- Bio-power: 11.75 GW
- Nuclear: 8.78 GW
Non-fossil sources now account for more than 54% of India's total installed electricity capacity.
Yet installed capacity and actual electricity generation are different concepts.
Prelims Concept: Capacity vs Generation
Installed capacity tells us the maximum rated capacity of power plants.
Electricity generation measures how much electricity they actually produce.
A 1 GW solar project cannot produce 1 GW continuously throughout the day because solar generation depends on sunlight.
Coal, nuclear and some hydropower facilities are comparatively more dispatchable, meaning their output can be increased or maintained when electricity is required.
This is why India can have more than half of its installed capacity from non-fossil sources and still remain heavily dependent on thermal power for reliable supply.
In FY 2025–26, non-fossil sources accounted for around 29.2% of total electricity generation, despite representing a much larger share of installed capacity.
The “Duck Curve” problem
Rapid expansion of solar energy creates a new operational challenge.
Solar generation increases strongly during daylight hours.
Therefore:
Morning: electricity demand rises before solar output peaks
Afternoon: large solar generation reduces demand from thermal plants
Evening: solar output falls rapidly while household electricity demand remains high
This creates a steep evening ramp in demand for other power sources.
A simplified pattern is:
Morning demand ↑ → Midday solar surplus → Sunset solar ↓ → Thermal/storage demand ↑
This is often associated with the duck curve phenomenon.
Coal plants that were historically designed to run steadily must increasingly reduce output during high-solar periods and ramp back up later.
Why energy storage is crucial
Renewable electricity becomes more valuable to the grid when surplus power can be stored and used later.
Two major storage options are:
Battery Energy Storage Systems
BESS can absorb electricity during periods of high solar or wind generation and discharge it when demand rises.
It is particularly useful for:
- evening peaks;
- frequency regulation;
- grid balancing;
- short-duration fluctuations.
Pumped Storage Projects
Pumped hydro uses surplus electricity to pump water to an upper reservoir.
When electricity is needed, the stored water flows downward through turbines.
It effectively functions as a large rechargeable energy system.
India is promoting both BESS and pumped-storage systems, but deployment has not yet grown at the same pace as renewable generation.
Analysts cited in current reporting have specifically pointed to limited battery-storage capacity as one reason coal plants remain under pressure during periods of high electricity demand.
Transmission is another bottleneck
Renewable resources are geographically concentrated.
Large solar resources are located in areas such as:
- Rajasthan;
- Gujarat;
- parts of southern and western India.
But major electricity demand centres may be hundreds or thousands of kilometres away.
This requires strong transmission corridors.
Rapid renewable capacity addition has at times moved faster than the infrastructure required to evacuate the electricity generated.
Transmission constraints can therefore create a paradox:
Renewable power available → grid unable to move all of it → renewable curtailment → thermal generation still required elsewhere.
Recent analysis has highlighted transmission congestion, delayed connectivity and insufficient storage as important constraints on India's clean-energy expansion.
What is renewable-energy curtailment?
Curtailment occurs when a power plant is technically capable of producing electricity but is asked to reduce or stop generation because the grid cannot absorb the output.
Possible reasons include:
- inadequate transmission;
- local grid congestion;
- low electricity demand;
- system-stability requirements;
- lack of storage.
This is particularly important for solar and wind because the primary energy source—sunlight or wind—cannot simply be stored unless electricity-storage infrastructure is available.
Why coal cannot simply be switched off immediately
India's energy transition operates under several simultaneous constraints.
The country must:
- provide affordable electricity;
- meet rapidly rising demand;
- maintain grid reliability;
- expand renewable energy;
- reduce emissions.
Coal currently provides an important balancing and baseload role while storage and flexible clean-energy capacity are still developing.
An abrupt withdrawal of coal without adequate alternatives could create:
- electricity shortages;
- grid instability;
- higher power costs;
- greater dependence on expensive gas;
- risks to industrial production.
The transition therefore has to be sequenced, not merely announced.
But increasing coal indefinitely is also not the solution
Coal combustion is carbon intensive and creates major environmental impacts.
These include:
- greenhouse-gas emissions;
- particulate pollution;
- sulphur and nitrogen emissions;
- ash generation;
- water consumption;
- mining-related ecological disruption.
India has committed to achieving 500 GW of non-fossil electricity capacity by 2030 and net-zero emissions by 2070.
Having already reached 300.50 GW, India has completed more than 60% of the 500 GW capacity target.
The policy objective therefore cannot be permanent dependence on coal.
It must be to use thermal power increasingly as a flexible bridge while storage, transmission and clean dispatchable power expand.
What is coal flexibilisation?
Traditional coal plants are designed to operate relatively continuously.
In a renewable-heavy grid, they increasingly need to:
- reduce output during strong solar generation;
- increase output rapidly after sunset;
- operate efficiently at lower loads.
This capability is called flexibilisation of thermal generation.
Flexible operation can create more space for renewable electricity without immediately retiring all thermal capacity.
However, frequent ramping also creates technical challenges such as:
- greater equipment wear;
- reduced efficiency;
- higher maintenance requirements.
Therefore, plants may require technological upgrades and revised operational practices.
Role of hydropower
Hydropower can complement solar and wind because some hydro stations can rapidly change output.
Reservoir-based hydro therefore provides:
- peak power;
- balancing services;
- grid flexibility.
But hydro itself is vulnerable to seasonal rainfall and reservoir levels.
The current coal-stock stress illustrates how lower water availability can shift additional load back onto thermal generation.
Climate variability therefore affects both electricity demand and electricity supply.
Climate change creates a double challenge
Extreme heat can increase electricity demand through:
- air conditioners;
- fans;
- refrigeration;
- cooling systems.
At the same time, climate-related variability can affect:
- reservoir levels;
- hydropower generation;
- renewable output;
- coal logistics during extreme rainfall.
Thus:
Climate change → higher cooling demand + greater supply variability
This makes grid resilience an increasingly important component of climate adaptation.
Energy security vs energy transition?
These objectives are sometimes presented as opposites, but India needs both.
Energy security requires reliable, affordable electricity.
Energy transition requires progressively reducing dependence on high-carbon energy.
The correct policy question is therefore not:
“Coal or renewable energy?”
It is:
How can India replace coal dependence without compromising reliability?
That requires an entire electricity-system transformation rather than simple addition of solar panels.
Way Forward
1. Accelerate energy storage
India needs rapid deployment of:
- battery energy-storage systems;
- pumped-storage projects;
- long-duration storage technologies.
Renewable expansion and storage expansion should increasingly proceed together.
2. Expand transmission ahead of generation
Transmission infrastructure should ideally be operational before large renewable clusters reach full capacity.
Green Energy Corridors and interstate transmission systems need faster implementation.
3. Modernise coal plants for flexible operation
Existing thermal plants that remain necessary during the transition should be upgraded for efficient low-load and ramping operation.
Older and inefficient units should gradually be retired where reliable alternatives exist.
4. Improve coal logistics in the short term
Until dependence declines, adequate railway rakes, pithead stocks and plant-level inventory management remain essential.
The present situation demonstrates that coal availability at mines does not automatically ensure coal availability at power stations.
5. Strengthen demand-side management
Electricity demand itself can be made more flexible.
Measures include:
- time-of-day tariffs;
- smart meters;
- efficient cooling;
- industrial demand response;
- energy-efficient appliances.
Consumers can then shift some electricity use away from peak periods.
6. Diversify clean dispatchable power
India should simultaneously expand:
- hydropower;
- nuclear energy;
- biomass where sustainable;
- green hydrogen-based applications over the longer term.
A diversified electricity mix reduces dependence on any single technology.
7. Improve forecasting
Better forecasting of:
- electricity demand;
- weather;
- solar output;
- wind generation;
can allow grid operators to schedule generation more efficiently.
Artificial intelligence and advanced weather models can support this transition.
Conclusion
India's current coal-stock stress does not mean that the renewable-energy transition has failed.
Instead, it reveals that the transition has entered a more difficult second phase.
The first phase was largely about adding renewable capacity.
The next phase must be about making that capacity reliable, dispatchable and fully integrated into the electricity system.
India has already crossed 300 GW of non-fossil installed capacity, an important achievement. But a modern power system also requires transmission, storage, flexible generation, demand management and reliable fuel logistics.
The central lesson is clear:
An energy transition is not merely a change in the source of electricity; it is a transformation of the entire power system.
Mains Practice Questions
Q1. India’s rapid expansion of renewable-energy capacity has not eliminated its dependence on coal-fired electricity. Explain the structural reasons behind this apparent contradiction.
15 Marks | 250 Words
Q2. Energy storage and transmission infrastructure are becoming as important as renewable-generation capacity for India's clean-energy transition. Discuss.
15 Marks | 250 Words
Sources
Reuters – Nearly a Third of India’s Coal Power Plants Face Critical Fuel Stocks
PIB / Ministry of New and Renewable Energy – India Achieves 300 GW Non-Fossil Fuel Capacity
PIB – India’s Energy Journey: Expanding Capacity, Strengthening Security
PIB / MNRE – India’s Renewable Energy Capacity and Power-Sector Progress
