Adani Electricity Mumbai Ltd. (AEML) has floated one of the country’s most significant energy storage tenders, calling for the development of 500 MW/4,000 MWh of energy storage capacity, along with an additional 250 MW/2,000 MWh option under the greenshoe mechanism. Issued in May 2025, the tender marks a critical move toward strengthening the city’s power supply infrastructure through advanced storage technologies.
This landmark tender by Adani Electricity allows developers to submit bids for either Battery Energy Storage Systems (BESS) or Pumped Storage Projects (PSP). It will be implemented under a Build-Own-Operate-Maintain (BOOM) model, with a contract duration of 40 years—a relatively long-term commitment that reflects the project’s strategic importance and expected lifecycle.
The selected project(s) will be required to support daily charging and discharging of 500 MW, with a minimum continuous discharge period of 5 hours per day. This is intended to address Mumbai’s growing energy demands, particularly during peak evening hours, and to improve grid stability, especially in the face of rising renewable energy penetration.
Under the performance obligations, the energy storage system must maintain a roundtrip efficiency of at least 75%, annual availability of 90%, and maximum cycle energy loss of 25%. These parameters aim to ensure dependable, efficient, and cost-effective operations over the long term.
To qualify, bidders must demonstrate relevant experience. PSP developers must have completed hydro or thermal projects or developed renewable projects equivalent to at least 1.5 times the offered capacity. BESS developers should have a strong track record in utility-scale storage projects.
The tender also outlines the following financial requirements:
- Earnest Money Deposit (EMD): ₹500,000 per MW
- Performance Bank Guarantee (PBG): ₹1 million per MW (payable after award)
- Bid processing fee: ₹300,000
- Document fee: ₹10,000
Developers have the flexibility to propose intra-state or inter-state transmission connectivity. Both greenfield and brownfield (under-construction) projects are permitted, provided they are not already contracted.
This tender is being seen as a game-changer in India’s energy storage space, not only for its sheer size but also for its focus on long-duration storage, which is becoming increasingly critical as the nation’s energy mix shifts toward variable renewables such as solar and wind.
The deadline for bid submissions is July 1, 2025, with bid opening scheduled for July 8, 2025. The results will be announced subsequently.
AEML’s initiative is expected to significantly boost investor interest in energy storage and could become a blueprint for other utilities aiming to secure 24/7 clean energy and grid resilience.
| Capacity | 500 MW / 4,000 MWh + 250 MW / 2,000 MWh greenshoe |
| Location | Mumbai distribution system (intra-/inter-state connectivity) |
| Results | Pending; bidding closes July 1 and results expected post-July 8 opening. |
