Parallel Operation Charges TANGEDCO: Who Still Pays in 2026

Tamil Nadu charges a captive generating plant ₹30,000 a month for every MW, or part of a MW, that it runs in parallel with the grid. The fight over it reached a tribunal verdict only in June 2025.

If you run a factory or commercial building with captive solar, a DG set synchronised to the grid, or a cogeneration plant, you need to know whether it still applies to you. For rooftop solar up to 999 kW it no longer does. Above 1 MW, and for DG and cogeneration, the answer differs.

This guide covers the charge, the orders and cases behind it, what a reverse power relay does, and a worked comparison for a 500 kW factory rooftop. It links to, rather than repeats, our pages on network charges, open access and captive rules.

Key takeaways

The rate is ₹30,000 per MW per month, under Regulation 26 of TNERC's 2014 Grid Connectivity and Intra-State Open Access Regulations, for plants that do not use open access.
APTEL ruled on 16 June 2025 that only plants that formally opted for parallel operation are liable, overturning TNERC's view that grid connection alone was enough.
Order 8/2021 ended parallel operation for solar up to 999 kW. Plants convert to net feed-in, the reverse power relay comes out, the charge stops, and network charges apply on generation.
Above 1 MW, TNPDCL still approves solar under parallel operation with reverse power relays, and a March 2022 TNERC order lets these plants pay network charges instead of the parallel operation charge.
Running in parallel without approval can cost you your supply on 3 days' notice, and your next application goes to the bottom of the list.

What parallel operation charges are in Tamil Nadu

A captive generator runs "in parallel" when it is synchronised with the grid instead of running on its own. The grid then absorbs load swings and harmonics, balances the phases, holds voltage when large motors start, and keeps the generator from tripping on sudden load loss. APTEL listed these benefits in its 2025 judgment and called the gain to a captive plant "quite substantial".

The parallel operation charge pays for that support. Regulation 26, notified on 7 May 2014, says a captive plant that opts for parallel operation pays ₹30,000 a month for each MW of capacity or part thereof. Three details matter:

It applies only without open access. A plant wheeling power pays open access charges instead.
It is per MW or part of a MW. On a plain reading, a 500 kW plant is billed for a full MW. Pro-rated, it would be ₹30 per kW a month.
Standalone generators are outside it. TANGEDCO's own methodology, as recorded by APTEL, says a generator not synchronised with the grid pays no parallel operation charge. A DG set on a changeover panel falls here.

The orders and the litigation

7 May 2014 - Forum: TNERC, What happened: Regulation 26 sets ₹30,000 per MW per month
2 May 2016 - Forum: TANGEDCO circular, What happened: Field offices told to collect the charge from 7 May 2014
22 March 2017 - Forum: Madras High Court, W.P. No. 2128 of 2017 and batch, What happened: Dispute sent to TNERC
4 January 2019 - Forum: TNERC, M.P. No. 10 of 2018, What happened: Any captive plant synchronised with the grid held liable
29 October 2019 - Forum: TNERC, M.P. No. 14 of 2018, What happened: HT solar under 1 MW allowed in parallel without a separate feeder until FY 2021-22, charge payable
1 March 2022 - Forum: TNERC, M.P. No. 1 of 2022, What happened: Loads of 1 MW and above may connect solar with a reverse power relay, paying network charges on all generation
16 June 2025 - Forum: APTEL, Appeal No. 162 of 2019 and batch, What happened: 2019 finding set aside; only plants that applied and paid the fee are liable

The 21 appellants included Suryadev Alloys and Power, Rajshree Sugars and Chemicals, and Chennai Petroleum Corporation, which had contested a demand for May 2014 to January 2019. APTEL held that "opt" in Regulation 26 means a choice made through the application and fee process, not mere electrical connection.

If you were billed the charge without ever applying for parallel operation, that judgment is your starting point. Take legal advice before claiming a refund, since TNPDCL can still go to the Supreme Court.

What a reverse power relay does

A reverse power relay watches the direction of power at your service connection. When power flows out of your premises into the grid beyond a set limit for a set time, it trips a breaker.

Under parallel operation, it enforces "no export". TANGEDCO's approval conditions, quoted in TNERC's 2019 order, required the relay on the consumer side and said any exported power would be neither adjusted against consumption nor paid for.

Most solar sites pair it with a zero-export controller that throttles the inverters to match the load. Either way, whenever your load falls below what the panels could produce, that sunshine is lost.

How Order 8/2021 changed things for solar up to 999 kW

TNERC's Order 8 of 2021, dated 22 October 2021, is still the order TNPDCL applies. TANGEDCO's salient features circular of 30 December 2021 says existing parallel operation "shall be converted" into net feed-in:

The reverse power relay is removed, so the plant can export.
Parallel operation charges cease.
Network charges apply on generation, read from a generation meter.
Exports earn the feed-in tariff: ₹3.10 a unit for 151 to 999 kW, ₹3.37 for 11 to 150 kW.
All generation on holidays can be exported, along with daily surpluses.

TNPDCL's "Policies adopted" note confirms HT solar of 1 to 999 kW is on net feed-in, with gross metering also open from 151 kW. Our guide to net metering vs net feed-in compares the mechanisms, and the solar export unit price covers payment.

The circular also sets the penalty. A plant found running in parallel without approval can have the consumer's supply disconnected with 3 days' notice, restored only once the plant is isolated. The consumer may reapply in the next financial year, at the bottom of the list. A behind-the-meter system that opts out of net metering and net feed-in is allowed, but only after prior intimation to TANGEDCO.

Since 14 September 2023, CMD Proceedings No. 198 has HT rooftop applications of 1 to 999 kW filed online with the Superintending Engineer of your distribution circle. TNPDCL has not published a separate conversion form for older parallel operation plants, so start there.

Solar above 1 MW: parallel operation is still the route

TNPDCL's note says solar above 1 MW is approved under parallel operation mode with reverse power relays. Export stays blocked.

The charge has changed, though. TNERC's 1 March 2022 order in M.P. No. 1 of 2022 lets loads of 1 MW and above connect solar up to contracted demand on their existing feeder with a reverse power relay, paying network charges on all units generated. TNERC's 2024 draft solar regulations describe this as network charges instead of parallel operation charges. That draft is not yet in force.

Plants approved under the older route may still carry the ₹30,000 per MW line. Check your HT bill.

Worked example: a 500 kW factory rooftop

Take a 500 kW HT factory rooftop near Chennai at 4.4 units per kW per day, about 8,03,000 units a year. It works six days a week and closes about 10 holidays, so 62 days are idle, with near-zero load. Working-day solar replaces grid power either way, so only holiday output and charges differ.

Holiday output, 62 days - Parallel operation (before 2021): 1,36,400 units curtailed, Net feed-in (now): 1,36,400 units exported
Export credit at ₹3.10 - Parallel operation (before 2021): Nil, Net feed-in (now): ₹4,22,840 a year
Parallel operation charge, full MW - Parallel operation (before 2021): ₹3,60,000 a year, Net feed-in (now): Nil
Network charge at ₹0.96 on 8,03,000 units - Parallel operation (before 2021): Nil, Net feed-in (now): ₹7,70,880 a year
Net position - Parallel operation (before 2021): Baseline, Net feed-in (now): ₹11,960 a year better

For a six-day factory, conversion roughly breaks even. Three inputs move it:

Base case - 6-day week, 62 idle days: ₹11,960 better, 5-day week, 114 idle days: ₹3,66,600 better
Network charge at ₹1.04 - 6-day week, 62 idle days: ₹52,280 worse, 5-day week, 114 idle days: ₹3,02,360 better
Charge pro-rated at ₹15,000 a month - 6-day week, 62 idle days: ₹1,68,040 worse, 5-day week, 114 idle days: ₹1,86,600 better

The ₹1.04 row is there because DT Next reports the HT network charge at ₹1.04 from 1 July 2024, while TNPDCL's note still lists ₹0.96. The example also ignores working-day surpluses at lunch breaks and shift changes, which net feed-in credits and a zero-export controller throws away. The real gap favours net feed-in more than the table shows.

Network charges are also in court. A single judge of the Madras High Court set them aside for industrial rooftop solar in a judgment published in March 2025. A Division Bench stayed that ruling on 28 April 2025 in one textile mill's appeal, and TNPDCL told offices in May 2025 to keep collecting. Our guide to rooftop solar network charges has the detail. Budget for paying them.

When each arrangement makes sense

Up to 999 kW, net feed-in suits factories with idle days. The more Sundays, holidays and light-load hours you have, the more the export credit outweighs the network charge.

Gross metering suits 151 to 999 kW sites with little daytime load. You sell everything at ₹3.10, pay no network charge, and buy back at the HT industrial energy charge.

Above 1 MW, size the plant to your minimum daytime load. Anything above your Sunday load is lost while network charges run on generation. On the order's wording, a larger factory can instead keep up to 999 kW on net feed-in. For more power, compare open access solar and an off-site captive solar plant.

For DG sets and cogeneration, ask whether you need synchronisation. A DG set on a changeover switch pays nothing. If your process needs a synchronised generator, apply and expect ₹30,000 per MW a month.

Never run solar in parallel without approval. Disconnection and the bottom of next year's list cost more than any charge you avoid.

Frequently asked questions

What is the parallel operation charge in Tamil Nadu?

₹30,000 a month for each MW, or part of a MW, of a captive plant that opts to run in parallel with the grid without open access. Regulation 26 of TNERC's 2014 Open Access Regulations sets it.

Do I pay parallel operation charges on rooftop solar?

Not if your plant is up to 999 kW and on net feed-in. Order 8/2021 converted such plants to net feed-in and ended the charge, with network charges applying on generation instead.

What is a reverse power relay in solar?

A protective relay that detects power flowing from your premises into the grid and trips a breaker. TNPDCL requires it where export is not allowed, which today means solar above 1 MW.

Who still pays parallel operation charges?

Synchronised DG sets, cogeneration and other captive plants that applied for parallel operation without open access. Solar plants on older parallel operation approvals may also still be billed it.

What did APTEL decide in June 2025?

Only captive plants that opt for parallel operation, by applying and paying the fee, are liable. It set aside TNERC's 2019 finding that grid connection alone created liability.

What happens if solar runs in parallel without approval?

TNPDCL can disconnect your supply on 3 days' notice, restore it only after the plant is isolated, and put your next application at the bottom of the following year's list.

Where this fits

For the size limits, see solar capacity and sanctioned load. For off-site options, see wheeling charges in TANGEDCO. Factory owners can start at industrial solar in Chennai or our commercial solar page, and test payback with the commercial solar ROI calculator.

Blues Renewables designs and installs commercial and industrial rooftop solar across Tamil Nadu from our Chennai base. We size the plant against your real load profile, Sundays and holidays included, show network charges and any parallel operation charge as separate lines, and handle the HT application, generation meter and inspection with TNPDCL. Every plant includes two years of free maintenance from commissioning. Send us twelve months of HT bills and we will tell you which arrangement pays for your site.

Call +91 98841 07170.

Sources

TNPDCL, "Policies adopted" note on the USRP portal, viewed 1 October 2026: Order 8/2021 adopted; HT 1 to 999 kW on net feed-in; above 1 MW under parallel operation with reverse power relays; feed-in tariffs; ₹0.96 HT network charge
TANGEDCO Technical Branch, salient features of TNERC Order 8 of 2021, 30 December 2021: conversion to net feed-in, relay removal, end of the charge, network charges on generation, holiday export, 3 days' notice, prior intimation rule
APTEL, judgment in Appeal No. 162 of 2019 and batch, 16 June 2025: Regulation 26 text and rate, 2014 notification, TANGEDCO's 2016 circular and methodology, the 2017 High Court direction, TNERC's 2019 order, benefits of parallel operation, the holding on opting
TNERC, order in M.P. No. 14 of 2018, 29 October 2019: TANGEDCO's approval conditions, including the relay and no payment for exports; the under 1 MW relaxation
Mercom India, 3 March 2022: TNERC ruling on solar for loads of 1 MW and above with a reverse power relay and network charges
TNERC, draft Grid Interactive Solar PV Regulations, 2024: describes M.P. No. 1 of 2022 dated 1 March 2022 as network charges instead of parallel operation charges; draft only
TANGEDCO, CMD Proceedings No. 198, 14 September 2023: HT rooftop applications of 1 to 999 kW filed online with Superintending Engineers
DT Next, 30 March and 14 May 2025: ₹1.04 HT network charge from 1 July 2024, the High Court ruling, TNPDCL's May 2025 instruction
Energetica India, 6 May 2025: Division Bench stay of 28 April 2025