India stopped pricing solar by fiat and let reverse auctions cut the price below coal

When India launched the Jawaharlal Nehru National Solar Mission in 2010, the regulator set a benchmark tariff of Rs 17.91 per kWh for solar photovoltaic power, and the nodal buyer NVVN allocated the first 150 MW of projects by discount bidding against it. Interest overwhelmed the window: 343 applications arrived for 30 five-megawatt slots. The winning 30 bids came in between Rs 10.95 and Rs 12.76 per kWh, averaging Rs 12.15 — roughly a third below the benchmark before a panel had been bolted down. The mechanism, not a technology breakthrough, had produced the first round of savings.

The design hardened over the following years. Capacity was aggregated into large, transparent tenders run by the Solar Energy Corporation of India, and solar parks assembled by state-backed joint ventures sold developers ready-made sites — at Bhadla in Rajasthan, charges of Rs 45.2 lakh per megawatt bought land, access and grid connection, so bidders no longer priced in land risk. In 2017 the government moved solar purchases under the Tripartite Agreement, which backstops payment defaults by state distribution companies, removing the risk that most spooked investors in Indian power.

The 2017 auctions showed what the pipeline did to price. On May 9, Phelan Energy and Avaada Power bid Rs 2.62 per kWh for Bhadla Phase IV — beating the previous record of Rs 4.34 and undercutting coal's roughly Rs 3.20. Three days later Phase III broke it again: ACME Solar took 200 MW at Rs 2.44 and SBG Cleantech 300 MW at Rs 2.45, tariffs fixed for 25 years with no escalation, and the winners sought no viability-gap funding at all. Twenty-four bidders had competed for eleven times the capacity on offer, including developers from Finland, France, Saudi Arabia, Singapore and Japan.

Auction the capacity; let bidders discover the tariff

A benchmark tariff protects whoever builds first; a reverse auction makes every builder defend its number against live rivals, so the discounting pressure never turns off.

Government fixed what only government could fix — land, grid connection, park infrastructure, payment security against discom defaults — and left to competition the thing markets do better: the price.

Aggregated demand drew global bidders: twenty-four of them chased 500 MW at Bhadla Phase III, so the clearing price settled near the true cost rather than the feared cost.

Winners took no viability-gap funding at Rs 2.44, which is evidence the auction discovered a genuinely bankable price rather than a subsidized one.

Split what government must set from what markets must find. Fix the quantity, de-risk what private capital cannot carry, and auction the price instead of administrating it.

The record set at Bhadla in May 2017 fell twice within three days, which is the point: each tender re-opened the race. Competitive reverse auctions became the standard way India allocates renewable capacity, displacing the case-by-case tariff-setting of the mission's first batch, and the per-unit price that had stood near Rs 18 in the 2010 cost-plus era was bid down to about Rs 2.5 by 2017 — cheap enough that analysts began asking whether new coal capacity still made sense in India at all.