The Solar Energy Corporation of India (SECI) has shared details of power capacities available for sale under various Inter-State Transmission System (ISTS) schemes as of July 15, 2025. These schemes encompass solar, hybrid, and round-the-clock (RTC) power projects with varying tariffs, timelines, and terms, awarded through competitive bidding.
Under the ISTS Tranche-XV (Solar + BESS), JSW Neo Energy Limited and ACME Solar Holding Limited have secured 500 MW and 200 MW, respectively, at a discovered tariff of INR 3.42/kWh. Power from these projects is expected to be commissioned within 24 months of the effective PPA date. A key feature of this scheme is the supply of half the contracted capacity during peak hours (18:00–24:00) for 2 hours.
The ISTS Tranche-XIV includes Avaada Energy Private Ltd. and ReNew Solar Power Private Ltd., each with 300 MW at INR 2.57/kWh. Similarly, ISTS Tranche-XIII includes 250 MW from NTPC Renewable Energy Ltd. at the same tariff. Tranche-XI has 300 MW by Eden Renewable Cadet Private Limited at INR 2.6/kWh. These schemes are not governed by the Uniform Renewable Energy Tariff (URET) mechanism, and the power is expected to be commissioned in 18 to 24 months.
ISTS Manufacturing Linked Solar Power scheme offers a significant 2,466 MW, with Azure Power India Pvt. Ltd. providing 667 MW at a base tariff of INR 2.42/kWh. However, after accounting for Basic Customs Duty (BCD) and GST, the effective tariff reaches INR 2.99/kWh. Adani Green Energy Four Limited contributes the remaining 1,799 MW. These projects are expected to be commissioned in 24 to 60 months.
Under the ISTS Hybrid Tranche-IX, Juniper Green, ACME Solar, and Sembcorp Green Infra are providing a total of 600 MW at tariffs around INR 3.25–3.26/kWh. Similarly, the Hybrid Tranche-VIII scheme includes 1,200 MW at INR 3.43–3.46/kWh, with participation from multiple developers including JSW Neo Energy and Avada Energy. These hybrid projects are governed by the URET mechanism.
ISTS Hybrid Tranche-VI includes 600 MW from developers such as AMP Energy Green and ReNew Vikram Shakti, offering high CUFs ranging from 52% to 72%. Tariffs for these projects range from INR 4.64 to INR 4.72/kWh.
ISTS FDRE-IV includes 630 MW from five developers, including JSW Neo and Serentica Renewable, with tariffs around INR 4.98–4.99/kWh. FDRE-VI has a peak hour-focused scheme offering 200 MW from Altra Xergi Power at a high tariff of INR 8.5/kWh.
ISTS RTC-IV offers 420 MW with tariffs ranging from INR 5.06 to 5.07/kWh. Strict penalties apply for non-compliance with monthly, annual, and peak hour DFR benchmarks, ranging from 1.5 to 1.75 times the cost of the shortfall.
Across all schemes, SECI’s trading margin of INR 0.07/kWh is applicable in addition to the discovered tariffs.
