Revision summary
Solar module and balance-of-system costs fell with Chinese scale and technology learning. India’s National Solar Mission used reverse bidding, which passed those cost drops into lower tariffs. Zero fuel cost and cheaper finance also cut the levelised tariff. Thermal plants risk lower plant load factor and stranded high-cost capacity in daylight hours. Coal, BHEL-type equipment and DISCOM PPAs must adjust; flexible thermal and storage remain necessary after sunset.
Model answer
Copper italics in this answer — like this — are the key facts. Each one is unpacked in the Facts & figures rail.
Introduction
Solar power in India moved in a few years from a costly niche to tariffs that began to undercut new thermal plants in some bids. The drop was not a miracle. It came from cheaper modules worldwide, scale in China, and reverse auctions under the Jawaharlal Nehru National Solar Mission. That trend rewrites the business of coal plants and their suppliers.
Body
Why equipment cost and tariffs fell
- Crystalline silicon module prices collapsed as global capacity, especially in China, outran demand; polysilicon and wafer costs followed.
- Balance-of-system costs (inverters, mounting, cables, land use) fell with standardisation and larger park size.
- India’s JNNSM and State policies used competitive reverse bidding, so developers bid down the tariff to win the power-purchase agreement.
- Cheap global finance after the financial crisis, and later dollar liquidity, lowered the cost of capital for solar, which is almost all upfront capex and zero fuel.
- Accelerated depreciation and renewable purchase obligations created a domestic buyer; solar parks cut land and evacuation delay.
- Oil and LNG price falls after 2014 did not cause the solar drop, but they changed the relative politics of energy; solar’s driver remained technology and auction design.
Implications for thermal power and related industry
- New coal plants face a shrinking room in the merit order when solar runs in daylight; plant load factor of thermal units can fall.
- Existing plants with high fixed costs and take-or-pay coal or gas contracts risk becoming stranded assets if DISCOMs prefer cheaper solar daytime power.
- Coal India, washeries, and rail-coal logistics see slower growth in domestic thermal coal demand than old plans assumed.
- Bharat Heavy Electricals and private boiler-turbine makers lose orders if capacity addition shifts from supercritical coal to solar modules (many of them imported).
- The grid still needs flexible thermal, hydro and, later, storage to back solar after sunset; a simple shutdown of coal is not the implication.
- DISCOMs must redesign PPAs and forecasting or they will pay for idle thermal capacity and cheap solar at once.
- Domestic module manufacturing lags China, so the tariff gain can widen the import bill unless local cell-module capacity is built.
Flow diagram
flowchart TD C[Cheaper global modules] --> A[Reverse auctions JNNSM] A --> T[Low solar tariffs] T --> P[Thermal PLF and new orders fall] T --> G[Grid still needs flexible backup]
Conclusion
Solar equipment and tariffs fell because modules got cheaper worldwide and India bought them through reverse auctions, not because coal suddenly vanished. Thermal producers face lower utilisation and fewer new orders; they remain needed for night and peak. Policy must pair cheap solar with a flexible coal-and-storage mix and with domestic manufacturing if the trend is not to export India’s equipment jobs.
Quick related
Students also ask
-
Did cheap oil cause cheap solar?
No. Solar costs fell mainly from modules, scale and auctions. Oil is a different market, though it changed the wider energy mood.
-
Should thermal plants close if solar is cheaper?
Not at once. Solar is variable. The grid still needs dispatchable thermal, hydro or storage when the sun sets.
Same topic · past papers
UPSC has asked this before
These previous-year questions sit on the same topic. Open one to practise the earlier ask.
More from this topic
Q11 · UPSC Mains 2026 · GS III · 15 marks · Solution
Explain the key challenges for India's energy security. What measures do you suggest for ensuring energy security along with economic growth and sustainability?
Infrastructure
India faces severe energy security challenges due to high import dependence for crude oil and gas, coal supply bottlenecks, and grid integration issues for renewables. To balance growth and sustainability, policy must combine domestic fossil fuel efficiency with rapid solar and green hydrogen scaling. Key steps include expanding strategic petroleum reserves, modernising transmission infrastructure, and promoting energy efficiency across industrial sectors. Ensuring energy access while reducing carbon intensity requires robust green financing and domestic manufacturing. Ultimately, India's long-term resilience depends on decoupling economic expansion from carbon emissions through systemic policy reforms.
Q6 · UPSC Mains 2026 · GS III · 10 marks · Solution
Differentiate between a Fast Breeder Reactor (FBR) and a thermal nuclear reactor. In the context of first indigenously developed prototype FBR at Kalpakkam, explain the term 'criticality'. What are its implications for clean energy future of our country?
Infrastructure
• Thermal reactors use slowed-down neutrons and uranium fuel with water coolant, while Fast Breeder Reactors (FBRs) use fast unmoderated neutrons, MOX fuel, and liquid sodium coolants to breed more fuel than they consume. • Reactor 'criticality' is the stable operating state where a nuclear fission chain reaction becomes self-sustaining, meaning neutron production equals neutron loss ($k_{eff} = 1$). • The recent first criticality of the 500 MWe Prototype Fast Breeder Reactor (PFBR) at Kalpakkam marks India's successful entry into commercial-scale fast reactor operations. • This milestone bridges the crucial gap between the second and third stages of India’s nuclear power roadmap, unlocking the path to utilize vast domestic thorium reserves. • FBR technology multiplies energy output from limited uranium resources, ensuring long-term domestic fuel independence. • It provides reliable, continuous baseload clean energy to effectively complement intermittent renewable sources like solar and wind. • Overall, the PFBR significantly accelerates India's transition toward national net-zero emission targets and energy security.
Q6 · UPSC Mains 2025 · GS III · 10 marks · Solution
How can India achieve energy independence through clean technology by 2047? How can biotechnology play a crucial role in this endeavour?
Infrastructure
India still imports most of its crude, so 2047 independence means much lower import intensity, not a sealed border. Clean electricity from solar, wind, storage and nuclear, plus green hydrogen and efficiency, are the main path. Electric mobility cuts oil only if the grid is cleaner. Biotechnology helps through biogas, second-generation ethanol from residue, industrial enzymes and less energy-intensive farming. Fuel-from-food is a poor version of that biotech role.