🗞️ Why in News The Solar Energy Corporation of India announced results of its 1,000 MW Round-the-Clock Thermal Mimic (RTC-TM) tender on August 7, 2026, at the 7th CII International Energy Conference and Exhibition, New Delhi. Tariffs were discovered between Rs 5.25 and Rs 5.26 per unit, the lowest yet for firm, dispatchable renewable power.
Ordinary Solar Versus Round-the-Clock
An ordinary solar tender sells variable power. The developer is paid for whatever electricity the sun allows, and the buyer, typically a distribution company, must arrange other sources to cover the hours the sun does not shine.
A Round-the-Clock (RTC) tender inverts the obligation. The developer must supply a contracted quantity of power in every time block across 24 hours, which means it cannot rely on solar alone. It must combine sources, solar by day, wind where the wind profile complements solar, and battery or other storage to fill the remaining gaps, so that the buyer receives power on the same predictable basis it would expect from a coal or gas plant.
This tender specifically used a “Thermal Mimic” structure, requiring 90 per cent assured availability in every time block, which is the design feature that makes the tariff meaningful. It is not a headline solar price. It is the price of power that behaves like baseload.
Why “Thermal Mimic” Is the Significant Word
Coal and gas plants have one structural advantage renewables have always lacked: they can be told to produce power at 3 a.m. as reliably as at 3 p.m. Variable renewable energy could not, by itself, replace that function, and every previous debate about a coal phase-down has run into the objection that renewables cannot provide firm capacity.
A Thermal Mimic tender is designed to test exactly that objection. By requiring the same 90 per cent time-block availability a thermal plant is expected to deliver, and discovering a tariff for it, the auction produces a direct, market-tested comparison between the cost of firm renewable power and the cost of new thermal capacity, rather than a comparison between renewable power at its best hours and thermal power at all hours.
What the Design Reveals
Solar contributed only about 50 per cent of daytime supply under the winning combinations, with the rest supplied by wind and storage. That split matters for the policy conversation about storage economics. India’s renewable capacity has grown overwhelmingly through solar, because solar module costs fell faster than any other component. A tender where storage and wind together do half the daytime work, and effectively all of the non-daylight work, is evidence that battery costs have fallen enough to be bid competitively into a firm-power contract, not merely used for short-duration grid balancing.
Seven developers were awarded capacity in this round, including Juniper Green Energy at 300 MW and Hexa Climate Solutions at 150 MW.
The Argument
The case for treating this as a turning point. A dispatchable renewable tariff below Rs 5.30 per unit is now within the range of new thermal capacity, and in many cases below it once a thermal plant’s fuel-price risk is priced in. If firm renewable power is cost-competitive with coal on coal’s own reliability terms, the strongest technical objection to accelerating coal retirement, that renewables cannot be dispatched on demand, weakens considerably.
The counter to engage. A single 1,000 MW auction result is not a national tariff. Bid prices in competitive renewable tenders have periodically undercut what later proves sustainable at scale, when developers bid aggressively for a landmark first-of-kind tender to establish a market position, and some winning bids in India’s renewable history have required subsequent renegotiation. The site-specific complementarity between solar and wind resources that allowed this tariff may not replicate everywhere storage-backed capacity is needed, and land and transmission constraints for hybrid projects are more binding than for single-technology solar.
Balanced verdict. The tender is genuine evidence that the technology and the cost curve now support firm renewable power at a competitive price, which was not true even a few years ago. Whether Rs 5.25 to 5.26 per unit is the price at which this can be delivered nationally, repeatedly, and without renegotiation is a question only a wider set of RTC auctions can answer, and that is the metric to track from here.
UPSC Relevance
GS Paper 3: Infrastructure, energy; conservation, environmental pollution and degradation; achievements of Indians in science and technology; economic development and issues arising from resource mobilisation.
Prelims focus: The RTC-TM tender structure and the 90 per cent assured-availability requirement; the distinction between variable and firm renewable power; India’s non-fossil capacity target of 500 GW by 2030; the role of SECI as the nodal renewable energy PSU.
Mains angle: “The strongest technical objection to coal retirement has been that renewables cannot be dispatched on demand.” Examine how Round-the-Clock renewable tenders are designed to test this objection, and assess the reliability of a single auction result as evidence of a broader cost trend.
📌 Facts Corner, Knowledgepedia
SECI RTC-TM Tender:
- Tender size: 1,000 MW, Round-the-Clock Thermal Mimic
- Discovered tariff: Rs 5.25 to 5.26 per unit, a record low for firm renewable power
- Assured availability requirement: 90 per cent in every time block
- Solar share of daytime supply under the design: roughly 50 per cent, balance from wind and storage
- Announced: August 7, 2026, at the 7th CII International Energy Conference and Exhibition, New Delhi
- Awarded developers include Juniper Green Energy (300 MW) and Hexa Climate Solutions (150 MW)
Institutional and Policy Context:
- SECI: Solar Energy Corporation of India, a CPSU under the Ministry of New and Renewable Energy, the nodal agency for large-scale renewable tendering
- India’s target: 500 GW of non-fossil-fuel capacity by 2030, under its updated Nationally Determined Contributions
- RTC tenders were first introduced by SECI in 2020 to address the intermittency limitation of variable renewable energy
Other Relevant Facts:
- Battery Energy Storage Systems (BESS) and pumped hydro storage are the two dominant grid-scale storage technologies currently deployed in India
- The Viability Gap Funding (VGF) scheme for battery storage, approved by the Cabinet, supports BESS project economics separately from tariff bidding
Sources: PIB, Ministry of New and Renewable Energy, SECI
Source: Rs 5.25: What It Costs to Make Renewable Power Behave Like Baseload — Ujiyari.com | Free UPSC & State PCS Current Affairs
