Onsite solar is limited by your roof. Open access is the route a large consumer takes when the roof runs out: buying solar power from a plant somewhere else in the state, delivered over the grid.
It is a genuinely useful mechanism and it is also the one most often explained badly, usually by someone quoting a tariff without the charges attached. Here is the shape of it for a commercial and industrial buyer in Telangana.
What open access is
Open access is the right of a large electricity consumer to buy power from a generator other than the distribution company, and to have it delivered over the existing transmission and distribution network. You keep your grid connection. The wires do not change. What changes is who you are buying from and what you pay them.
For solar, this means a plant built somewhere with land and good irradiation can supply a factory that has neither. The eligibility threshold is set in law and in state regulation, and it is aimed at large consumers, not small ones.
The three ways to structure it
- Third-party sale. An independent producer owns the plant and sells you the power under a long-term agreement. Closest thing to an onsite PPA, just not on your site.
- Captive or group captive. You take an equity stake in the generating company and consume a proportionate share of the output. The captive rules on ownership share and consumption share have to be met and maintained, not just at signing but every year afterwards.
- Power exchange. Buying through the exchange on a short-term basis. Flexible, and exposed to market price, which is the opposite of what most C&I buyers are trying to achieve.
Where the money actually goes
This is the part that gets left out. The generation tariff is not what you pay. On top of it sit a set of charges for using the network and for the consumers you are leaving behind:
- Transmission charges for using the state transmission network.
- Wheeling charges for using the distribution network.
- Cross-subsidy surcharge, which compensates the DISCOM for the subsidised consumers your tariff was helping to support.
- Additional surcharge, where it applies, covering the DISCOM’s stranded fixed costs.
- Losses, applied in kind on the energy injected.
- Banking and scheduling terms, which decide what happens to energy generated when you are not consuming it.
Whether open access beats your grid tariff is entirely a question of what these add up to for your connection. We do not publish the figures here, because they are set by orders of the Telangana State Electricity Regulatory Commission and they are revised. A number in a blog post is out of date the moment an order lands. Get the current schedule, in writing, applied to your own connection.
Banking is the clause to read twice
Solar generates in the day. Your factory may not consume all of it in the day. Banking is the arrangement under which surplus energy is credited and drawn down later. The terms decide how much of your generation you actually get to use.
Read what the current order permits: whether banking is allowed, over what period it settles, what charge applies to banked units, and what happens to units left unbanked at the end of the settlement period. Two projects with identical tariffs can produce very different bills because of this clause alone.
Open access or onsite?
| Onsite solar | Open access solar | |
|---|---|---|
| Where the plant sits | Your roof or your land | Elsewhere in the state |
| Size limit | Your usable area | Effectively your consumption |
| Network charges | None: the power never leaves your premises | Transmission, wheeling, surcharges, losses |
| Regulatory exposure | Low | Charges and banking terms can change by order |
| Setup time | Around 90 days for the build | Longer: approvals and registration |
| Best used for | The first slice of your load | What is left after the roof is full |
What we would tell a Telangana factory to do
Fill the roof first. Onsite solar has no network charges, no cross-subsidy surcharge, no banking clause and no regulatory exposure on the delivery side. It is the cleanest rupee of saving available to you, and for most single-site factories it covers a meaningful share of daytime load on its own.
Then look at open access for the remainder, with the current charge schedule applied to your own connection and the banking terms read properly. If the two together are structured well, a large consumer can cover most of its daytime energy with solar.
We build onsite plants, and we supply through open access arrangements. Our own open access plants in Telangana are listed on the projects page, and we will run both options on your own bills.