The Financial Express reported on 11 October that India Inc is switching to captive green power "to cut costs and grid reliance." It reads like a renewables story — buy the solar names. The filings say something more specific: the saving is real and large, and it is being booked on the P&Ls of cement and chemical companies, not the developers building the plants.

The boom is a mix shift, not a volume boom

Waaree Renewable Technologies' FY26 annual report has the number nobody quotes. India added a record 36.6 GW of solar in calendar 2025. Of that, open-access solar — the route industrial buyers use — was 7.80 GW, "a marginal 0.5% increase over 2024." Flat. Karnataka alone took more than 24% of open-access installs, followed by Maharashtra (over 20%) and Rajasthan (over 18%).

So corporate India is not suddenly buying far more green power. It is restructuring how it buys — moving from third-party open access toward the group captive structure, where the buyer must hold at least 26% of the project equity and consume 51% of the output, as CleanMax spells out in its own glossary.

Where the money shows up: the buyer's power line

UltraTech Cement publishes the cleanest arbitrage table in Indian industry. Per its Q3 FY26 investor presentation, its grey-cement power sources were:

Renewables cost ₹3.0 a unit less than grid power. In Q3 FY25 they were just 12.7% of the mix; a year later, 20.6%. Blended power cost fell from ₹5.8/kWh to ₹5.1, and power cost per tonne of cement from ₹409 to ₹349 — down 15% year on year. Its Q2 FY26 deck put the total green power mix (renewables plus WHRS) at 41.6% against 30.2% a year earlier, with a target of 85% by FY30. That is the whole trade in one table: a cement company swapping ₹7.4 power for ₹4.4 power across a fifth of its load. Dalmia Bharat shows the same pattern. Its FY26 annual report puts renewable energy share at 46%, up from 36%, with installed non-fossil capacity rising 68% to 449 MW, and credits "participation in group captive renewable models." On its Q3 FY25 call management said it had signed 299 MW of group captive agreements cumulatively, while chasing a further ₹150–200 per tonne of savings. Orient Cement reports green power at 41% of electrical energy in FY26 — 15% WHRS, 18% wind, 8% purchased solar — targeting 60% by FY28.

Outside cement, Gujarat Alkalies and Chemicals is the most literal example. Its board statement of 29 May 2026 says the company "could reduce energy cost as compared to previous year on account of increased share of renewable power," with the renewable share rising to 35.7% in FY26 from 29.7%. Its FY26 annual report discloses 171.45 MW of wind and 35 MW of solar, plus an SPV formed with Clean Max Enviro for 75.9 MW of hybrid captive power — Phase I (16.5 MW) due October 2026, Phase II (59.4 MW) by March 2027.

The other side of the trade: the developer's tariff is falling

CleanMax Enviro Energy Solutions is the pure-play here, and its disclosure is unusually honest about the price of winning this business. Operating capacity reached 4,174 MW in the June 2026 quarter against 2,213 MW a year earlier, with group captive at 48% (1,995 MW) of that book and another 2,657 MW under execution.

Now the tariff. CleanMax's weighted average realised tariff has fallen every year: ₹4.95/kWh in FY23, ₹4.47 in FY24, ₹4.28 in FY25, ₹4.20 in FY26 and ₹4.06 in the June 2026 quarter. More tellingly, the tariff on PPAs newly commissioned during FY26 was ₹3.57/kWh, and its FY26 annual report prices the whole under-execution book at ₹3.85/kWh — locked in for a weighted average 23.17 years.

This is not distress. Portfolio EBITDA margin is guided at 83–84%, run-rate EBITDA has gone from ₹476 crore (April 2023) to ₹1,870 crore (April 2026), and 74% of new volume is repeat business. But cash ROIC was 13.03% and net debt sits at 5.0–5.5x run-rate EBITDA. Every rupee the buyer saves comes out of a tariff fixed for over two decades on a leveraged asset.

Note also who is driving the growth. CleanMax's March 2026 deck shows 42% of contracted capacity coming from "Data & AI" customers, alongside repeat industrial buyers including UltraTech, Apar Industries, BASF, Gujarat Alkalies and CEAT. The captive rush is as much a data-centre story as a manufacturing one.

KPI Green Energy makes the capital structure explicit. Its captive (CPP) vertical contributed 87% of revenue as of Q1 FY25, and its FY26 annual report describes the model as letting clients "capture the sizeable arbitrage between captive generation and DISCOM-supplied power." Critically, in CPP "customer capital funds the build" — lower capital intensity for KPI, but the asset risk sits with the industrial buyer. It is working: 9M FY26 revenue of ₹1,900 crore rose 63% and FY26 PAT was ₹476 crore, with EPS of ₹24.13 against ₹16.23.

What retail investors should do

Treat "India Inc goes captive" as a margin story in cement and chemicals before a growth story in renewables. The recurring gain sits on the buyer's cost line, and UltraTech, Dalmia Bharat, Orient Cement and Gujarat Alkalies all quantify it in their own filings — track the green power mix and power cost per tonne (or per kWh) each quarter. On the developer side, do not assume capacity growth equals earnings growth: CleanMax's realised tariff has fallen four years running and new contracts sign near ₹3.6–3.9/kWh for 23 years, so capacity added today earns less per MW than the existing book. And if a company you own announces a group captive deal, remember it is taking a minimum 26% equity stake in a power SPV — CleanMax's FY26 annual report notes these SPVs become related parties once the customer buys in. That is a balance-sheet commitment, not just a procurement contract.

Data sourced from company filings on NSE via Xaro.