ACME Solar Wins 130 MW Railways RTC Tender At ₹4.35 Per Unit
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- Last Updated: 18 Dec 2025 at 10:26 PM IST
ACME Solar Holdings has emerged as the successful bidder for 130 MW in the Railways Energy Management Company’s round-the-clock (RTC) renewable energy project tender. The e-reverse auction closed with ACME quoting ₹4.35 per unit, one of the more competitive prices seen for firm renewable supply this year. Indian Railways will sign a direct long-term power purchase agreement (PPA) once the award is issued and the standard checks are completed.
The contract requires high availability across the year. Developers need to maintain 75% annual availability for the first three years of operation and 85% after that. To reach those levels ACME will combine solar, wind and a sizeable battery storage system, drawing on land and transmission capacity already present in its portfolio. The project has a commissioning window of 30 months from the date of signing, a timeline that ACME says is realistic given its existing assets and internal execution teams.
As tenders shift towards firm renewable supply rather than pure energy bids, one question sits at the centre of this transition. Can these hybrid systems consistently deliver power at the price discovered in this auction?
Constant Load Over Peak Power
The railways operate on a near-constant power load across stations, depots and control systems. Unlike industries that see morning and evening spikes, the railways consumes steady power through the day. This makes intermittent solar less suitable as a standalone source.
Because of this, the latest tender focuses heavily on reliable, round-the-clock delivery, not just low-cost generation. Bidders therefore need to plan how much energy they can supply every hour and in every season, instead of only adding solar capacity on paper.
The design also encourages oversizing. Developers typically install more solar capacity than the contracted requirement so that the battery can charge even during short winter days or cloudy spells. Adding wind in suitable states strengthens the system further, especially during evenings and in months when solar output dips. These practices have become more common this year as equipment prices changed and early hybrid projects provided more real world performance data.
The Railways has also structured this tender as a direct PPA with itself as the central buyer. With one buyer and a unified operational footprint, the process avoids multiple approvals and clearly assigns performance responsibility to the developer. This kind of clarity is important when the availability clauses are strict and penalties for non-delivery are likely.
What Is ACME’s Strategy?
ACME enters this tender with a portfolio that already spans 2,934 MW of operating capacity and 4,456 MW under development. A notable portion of this pipeline includes 13.5 GWh of battery storage. The company’s in-house engineering and operations units give it more control over construction timelines and long-term plant behaviour, which tends to help in performance linked contracts.
In 2025, ACME increased its Rajasthan solar capacity, placed multi-GWh BESS orders and signalled a strong move into hybrid/storage solutions.
For ACME, the Railways award extends its shift towards firm renewable solutions rather than standalone solar. The economics are more complex, but the long-term revenue visibility can be stronger when availability is tied to a single large buyer with predictable demand.
What Is The Overall Sector Trend?
Round-the-clock procurement has slowly become the preferred route for electricity-intensive sectors. Data centres, metal producers and transport networks have shown interest in predictable, contract-based green power that sidesteps the volatility of shorter market trades. Developers have responded by building diversified portfolios that draw energy from multiple states and by expanding battery storage as a key balancing tool.
The Railways is moving in the same direction. It has rooftop installations, open access arrangements and now a major utility scale RTC programme as part of its pathway towards its 2030 emission goals.
As storage technology improves and hybrid designs mature, could upcoming RTC auctions settle at even lower tariffs?
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