Soon after launching a large-scale solar and storage tender under ISTS tranche XX, India’s SECI has opened another round of these hybrid assets under ISTS tranche XXI. (Illustrative Photo; Photo Credit: The Desert Photo; /Shutterstock.com)  
Tenders

SECI Launches ISTS-XXI Solar & Storage Capacity Tender

New SECI tender aimed at boosting hybrid solar and storage projects

Anu Bhambhani

  • SECI seeks bids for 1.2 GW solar with 600 MW/3,600 MWh energy storage projects  

  • For every 1 MW solar power capacity, a 0.5 MW/3 MWh ESS addition is mandatory 

  • Projects must use ALMM-listed modules and cells, with 25-year PPAs and 24-month commissioning 

The Solar Energy Corporation of India (SECI) has launched a tender to seek solar power developers for 1.2 GW Inter-State Transmission System (ISTS) connected solar PV projects with 600 MW/3,600 MWh energy storage systems (ESS) under tranche XXI.  

All winning projects can be located anywhere in India. Bidders will be responsible for the identification of land, installation and ownership of the project, as well as for securing necessary approvals and interconnection with the ISTS network/state transmission utility (STU) for the supply of power to SECI.

For every 1 MW solar project capacity, an ESS of at least 0.5 MW/3 MWh is mandatory. A single bidder can submit a bid for a minimum capacity of 50 MWand a maximum of 600 MW, quoting capacity in multiples of 10 MW.

The solar PV modules and cells used in these projects must be from the Approved List of Models and Manufacturers (ALMM) List-I (modules) and List-II (cells). 

Winning projects will enter into 25-year power purchase agreements (PPA) with SECI. Selected facilities need to be commissioned within 24 months from the date of signing the PPA. 

SECI launched the tender on June 19, 2025. The last date of bid submission is August 20, 2025. 

This tender follows SECI’s ISTS tranche XX call issued recently for 2 GW solar with 1,000 MW/4,000 MWh ESS capacity (see India’s SECI Launches 2 GW Solar & Storage Tender).  

According to Mercom India Research, the tender and auction activity slowed down in India in Q1 2025, owing to a backlog of power sale agreements. India had 127.8 GW worth of solar projects tendered and awaiting auction at the end of the reporting quarter (see India Installed 6.7 GW New Solar Capacity In Q1 2025).