Solar Open Access Savings Calculator

Open access lets a consumer buy power from a generator other than the local DISCOM — typically a solar plant off-site — wheeled over the grid. Under the Green Energy Open Access Rules, 2022, consumers with 100 kW and above of contracted demand can seek green energy open access, which brought mid-sized factories into a market that used to start at 1 MW. State regulations implement the details, and they differ.

Wheeling and transmission charges, cross-subsidy surcharge (CSS), additional surcharge, banking charges or in-kind banking deductions, and losses in the state network. A ₹3.50 PPA can land at ₹5.50–6.50 after charges depending on the state and voltage level — which is why this calculator asks for the landed open-access rate, not the PPA sticker price.

They stack rather than compete. Rooftop behind the meter avoids the full retail tariff with no wheeling charges, so it is almost always the first move — but the roof caps its size. Open access then serves the demand your roof cannot, at a saving per unit that is smaller but applies to much larger volumes. Most large consumers end up with both.

In a third-party PPA you simply buy power from someone else's plant. In captive or group-captive structures you hold equity in the generating plant (26% equity and 51% self-consumption are the commonly applied tests), which under current rules can waive the cross-subsidy surcharge — often the single biggest charge. The right structure is a legal-financial decision as much as a technical one; the current state order decides what works.