A normal solar tender buys electricity. A round-the-clock tender buys reliability. That one word is the whole difference, and it is the reason every serious RTC bid in India now has a battery in it.
In an ordinary solar or wind auction, the DISCOM (distribution company) agrees to take whatever the plant produces and pays a per-unit tariff for it. If a monsoon week wipes out output, that is the buyer’s problem. An RTC tender flips the risk. The developer commits to making an agreed share of the contracted capacity available in every hour of the year, and gets penalised for falling short. Since no solar panel generates at 9 pm, the only way to keep that promise is to store energy earlier and release it later.
What “round the clock” actually obliges you to do
RTC contracts are written around an availability or CUF (capacity utilisation factor) figure — the share of the plant’s contracted capacity actually delivered over a period. Three numbers usually appear together:
- an annual minimum, the headline commitment;
- a monthly minimum, so a developer cannot bank a good winter against a bad summer;
- a peak-hour obligation, which is the hardest one, because peak hours in India fall in the evening when solar output is zero.
SECI’s 2025 round, for example, required availability of 75% monthly, 80% annually and 90% during peak hours. That last figure is the storage-forcing clause. A solar-heavy portfolio simply cannot deliver 90% of contracted capacity during an evening peak without a battery discharging into the grid.
How the rounds have evolved
India’s RTC programme has run for several years now, and each round has asked for more.
RTC-1 (2020). SECI tendered 400 MW. ReNew Power won the entire block at ₹2.90/kWh with a 3% annual escalation for the first 15 years of a 25-year PPA (power purchase agreement), which works out to an effective tariff of roughly ₹3.59/kWh. The obligation was 80% annual and 70% monthly CUF.
RTC-2 (2020). The bar rose to 85% annual CUF, plus a requirement to dispatch during any four “peak” hours a day as designated by the Regional Load Despatch Centre. ReNew again took 600 MW, at ₹3.19/kWh.
The 2025 round. SECI sought 1.2 GW of RTC power sourced entirely from renewables with storage. It attracted bids for only 540 MW and finally awarded 420 MW at an average of about ₹5.06/kWh — Hero Future Energies 120 MW and Hexa Climate Solutions 100 MW at ₹5.06, Jindal India Power 150 MW and Sembcorp Green Infra 50 MW at ₹5.07. The PPA term is 25 years.
The 2026 step change: RTC “Thermal Mimic”
In March 2026 SECI issued a Request for Selection for 1,000 MW of RTC Thermal Mimic (RTC-TM) power. The name is the clearest statement of intent yet: the project is meant to behave like a coal plant, delivering firm, dispatchable output on demand.
The obligations are framed as a Demand Fulfilment Ratio — 90% during peak demand hours, 80% off-peak, and 90% on an annual average, with some seasonal flexibility. Individual projects run from 100 MW to 500 MW per bidder, the technology mix is left to the developer, and energy storage is mandatory. The PPA runs 25 years, supply is to begin 18 months from the effective date, and tariffs are discovered through a single-stage two-envelope process followed by an electronic reverse auction.
| Round | Capacity | Key obligation | Discovered tariff |
|---|---|---|---|
| RTC-1 (2020) | 400 MW | 80% annual / 70% monthly CUF | ₹2.90/kWh (3% escalation) |
| RTC-2 (2020) | 600 MW | 85% annual CUF + 4 peak hours | ₹3.19/kWh |
| 2025 round | 420 MW awarded of 1.2 GW | 80% annual, 90% peak | ~₹5.06/kWh |
| RTC-TM (2026) | 1,000 MW | 90% peak / 80% off-peak DFR | Bidding stage |
RTC versus FDRE — a fair question
Buyers and developers often use the two terms interchangeably, and the confusion is understandable. Both procure firm renewable power backed by storage. The practical distinction is how the requirement is written: an RTC tender is framed around a round-the-clock availability or CUF number, while an FDRE (Firm and Dispatchable Renewable Energy) tender usually specifies how much power must be delivered in defined time blocks across the day. We cover that structure in detail in the FDRE tender framework explainer, and the closely related standalone route in our guide to SECI standalone storage tenders.
From an equipment standpoint the answer is the same in both cases — you are building a renewable firming asset, and usually a solar-wind-plus-storage hybrid, because combining two generation resources reduces how many hours of battery you have to buy.
Why these tenders get undersubscribed
The 2025 round is instructive. SECI wanted 1.2 GW and received bids for 540 MW; under the rule that 80% of quoted capacity is awarded, the final number came to 420 MW, with the last bidder’s 12 MW dropped for falling under the 50 MW minimum.
Two things are going on. First, the obligations are genuinely hard, and a developer who misjudges the storage sizing carries that penalty for 25 years. Second, RTC competes for developer attention against simpler standalone storage tenders that pay a fixed monthly capacity charge without any generation risk at all. Anyone weighing the two should read our note on how BESS duration is chosen, since duration is the single biggest cost lever in an RTC bid.
What this means for you
- If you are a developer or IPP: treat the peak-hour obligation, not the annual CUF, as the design constraint — it sets your battery’s power rating and duration. Model a bad monsoon month against the monthly minimum before you quote, because that is where RTC portfolios usually fail.
- If you are a DISCOM: RTC buys you dispatchable clean capacity without building generation yourself, but expect to pay a premium over plain solar — roughly ₹5/kWh versus ₹2.5–3/kWh territory — and expect thin participation if the obligations are set aggressively.
- If you are a C&I (commercial and industrial) buyer: the RTC structure is the model behind most firm green-power offers you will be quoted. Ask what availability the supplier has actually committed to contractually, and in which hours.
Tender terms, availability obligations and discovered tariffs change by notification and vary round to round; the figures here are a July 2026 snapshot, and you should verify current provisions in the live RfS documents from SECI before committing to a bid. To see what storage duration your own load or portfolio would need, try our BESS savings calculator or get in touch with our team.
Policy snapshot as of July 2026. Tender terms, CUF and availability obligations, VGF eligibility and discovered tariffs change by government notification; verify current provisions with SECI, CERC and Ministry of Power documents before financial decisions.