IEX Green Day-Ahead Market: A C&I Buyer's Guide

Direct Answer

The IEX Green Day-Ahead Market (G-DAM) lets open-access-eligible industrial and commercial consumers in North India buy certified green power for next-day delivery through a double-sided closed auction on the Indian Energy Exchange. You participate with the same short-term open-access approval you already use for conventional exchange purchases, in minimum 0.1 MW blocks, with no capex and no long-term lock-in. Discovered prices have recently moved between roughly ₹3.15 per unit (September 2025) and ₹4.21 per unit (December 2025), so G-DAM works best as a flexible, zero-capex green top-up alongside rooftop or group-captive solar — not as a full replacement for either.

TL;DR

• G-DAM launched on 26 October 2021 under CERC's order dated 17 October 2021 (Petition 146/MP/2021) and runs inside IEX's existing day-ahead auction, with solar, non-solar and hydro categories and minimum 0.1 MW blocks.
• Green Market volumes (G-DAM plus G-TAM) reached 3,040 MU in Q2 FY26, up 17.7% year-on-year, and 2,647 MU in Q3 FY26, up 7.2%, with over 5,700 open-access consumers registered on the exchange.
• Compared below: rooftop capex solar, group-captive solar and G-DAM purchases across capex, price class and risk.
• A green real-time market has been petitioned but not yet notified; CERC's final VPPA guidelines of 24 December 2025 open a separate, exchange-settled long-term route.

What the G-DAM is and how it clears

The Green Day-Ahead Market went live on 26 October 2021, following CERC's order dated 17 October 2021 in Petition 146/MP/2021. Rather than creating a separate exchange, IEX integrated the green segment into its existing Day-Ahead Market: the same engine runs a double-sided closed auction, in which buyers and sellers submit price-quantity bids without seeing each other's orders, and the market clears for delivery on the next operating day.

Three design details matter for industrial buyers:

• Green categories. Power is tagged as solar, non-solar or hydro, so buyers can direct purchases toward the generation type their strategy requires.
• Small minimum blocks. Contracts trade in minimum 0.1 MW blocks, keeping the market accessible to mid-sized factories, not only very large consumers.
• One integrated market. G-DAM shares liquidity and clearing with the regular DAM rather than splitting into a thin side market.

A live G-DAM day clears on the order of 20,000-25,000 MWh (an October 2026 snapshot showed roughly 23,664 MWh), and the broader Green Market — G-DAM plus the Green Term-Ahead Market — delivered 3,040 MU in Q2 FY26 and 2,647 MU in Q3 FY26.

Who can buy, and through whom

Eligibility follows open access, not exchange membership. All open-access-eligible entities — including C&I consumers buying through traders or their own open access — can purchase on G-DAM using the short-term open-access NoC they already obtain for conventional exchange purchases. IEX reports more than 5,700 open-access consumers registered on the platform. If open access is new territory for your plant, see open access solar in India and capex, opex and open-access routes.

Operationally, participation runs through the same machinery as short-term open access: the state load dispatch centre grants the NoC, a registered trader handles scheduling and coordination, and your existing banking arrangements carry the energy. Most factories do this through their power trader.

What G-DAM power has actually cost

IEX publishes weighted average discovery prices for G-DAM. Two recent data points frame the range: roughly ₹3.15 per unit in September 2025 and ₹4.21 per unit in December 2025 — a swing of about a rupee per unit inside a single quarter.

Two honest cautions when comparing these numbers with your HT bill:

• Open-access charges sit on top. The cleared price is not your landed price. Wheeling, banking and additional surcharges under your state's open-access framework add to it, so model landed cost state by state.
• The price floats. Unlike a 25-year rooftop asset, G-DAM provides no long-term hedge. You re-price every single day.

Even so, green power discovered in the roughly ₹3-4 per unit range compares favourably with typical HT energy charges in North India before open-access adders — which is why volumes keep growing.

G-DAM vs rooftop capex vs group captive

For a decision-maker, the choice is rarely either-or. Here is how the three routes compare:

Where G-DAM wins, and where it falls short

Where it wins: zero capex and zero O&M; seasonal flexibility (buy more in peak months, less otherwise); and green-tagged volumes for ESG reporting and renewable procurement targets without deploying capital.

Where it falls short:

• No price hedge. The roughly one-rupee-per-unit swing between September and December 2025 cuts both ways — a factory sourcing all its power through G-DAM re-prices daily.
• Charge exposure. Open-access charges and losses stack on top of the cleared price, and these vary by state and change with regulatory orders.
• Discovery risk. When IEX petitioned CERC in April 2025 for a green real-time market, it cited unmet G-DAM buy bids of 72% in FY24 — in other words, buyers' demand did not always clear.

The practical pattern for many North Indian manufacturers: rooftop solar sized for daytime base load, G-DAM as a flexible green top-up.

How to participate, step by step

1. Confirm open-access eligibility for your connection and state.
2. Obtain or maintain your short-term OA NoC from the state load dispatch centre.
3. Onboard through a registered trader with scheduling and banking arrangements in place.
4. Place day-ahead bids in minimum 0.1 MW blocks, tagged to the green category you need.
5. Track landed cost, not just cleared price — add wheeling, banking and surcharges to measure the true ₹/unit.

What to watch next: G-RTM and VPPAs

Two developments will reshape this market. First, a green real-time market has been petitioned but not yet notified — IEX approached CERC in April 2025, citing the 72% unmet buy bids in FY24. When notified, it would let buyers mop up short-notice green volumes in real time. Second, CERC issued final VPPA guidelines on 24 December 2025, enabling exchange-settled green contracts for C&I consumers — a structurally different, longer-tenor route worth understanding; see our 2026 explainer on India's VPPA rules.

Frequently Asked Questions

Can a factory in Delhi-NCR buy directly on G-DAM?

Yes, provided it is open-access-eligible and holds a valid short-term open-access NoC. Most factories participate through a registered power trader who handles bidding, scheduling and coordination, rather than dealing with the exchange directly.

How large does my load need to be?

G-DAM trades in minimum 0.1 MW blocks, small enough for most HT industrial and commercial consumers. The binding constraint is open-access approval in your state, not exchange membership or size.

Is G-DAM cheaper than rooftop solar?

It depends on your objective. Recent G-DAM weighted averages of roughly ₹3.15-4.21 per unit (before open-access charges) look attractive against grid tariffs, but the price floats daily. Rooftop capex solar requires roughly ₹23,000/kW at 100 kW scale (excl. GST) but fixes your generation cost for decades. Many buyers use both.

Does G-DAM power help with renewable obligations and ESG goals?

Purchases on G-DAM are tagged green by category (solar, non-solar, hydro), giving you documented renewable volumes that can support ESG reporting and renewable procurement commitments. Verify the exact treatment under specific compliance frameworks with your consultant, since rules continue to evolve.

What happens if my buy bid does not clear?

It remains unmet — you get no power from that auction and must fall back on grid supply or another arrangement. Unmet buy bids were a significant share of G-DAM activity (72% in FY24, per IEX's petition), which is why a green real-time market has been petitioned but not yet notified."