Direct Answer: Tamil Nadu Open Access Solar Charges FY2026-27
For FY2026-27 (April 2026 – March 2027), the total landed cost of open access solar in Tamil Nadu ranges from approximately ₹4.00–₹4.60 per unit for captive consumers and ₹5.80–₹7.20 per unit for third-party open access consumers. The key charges are: wheeling ₹0.35–₹0.55/unit (voltage-dependent), cross-subsidy surcharge (CSS) ₹1.00–₹1.50/unit for third-party OA (exempt for captive), additional surcharge ₹0.10–₹0.54/unit (under review for H2 FY2026-27), transmission ₹0.40–₹0.60/unit, and 8% banking charge in kind for captive/group captive consumers under the TNERC GEOA Regulations 2025.
TL;DR: Captive solar in Tamil Nadu lands at ~₹4.15/unit while third-party PPA lands at ~₹6.40/unit — the CSS and additional surcharge exemption alone saves ₹1.50–₹2.50/unit, making the captive or group captive structure the economically dominant choice for C&I consumers in the state.
Last verified: 7 October 2026. Figures are based on TNERC Tariff Order No.6 of 2025 (effective 01-07-2025), TNERC GEOA Regulations 2025 (effective 01-10-2025), and secondary sources. FY2026-27 open access surcharge orders are pending TNERC notification as of this date — confirm the current additional surcharge and wheeling rates with TNPDCL before financial modelling.
Table of Contents
- TANGEDCO, TNPDCL, and TNGECL: Entity Guide
- What Changed in FY2026-27
- Voltage-Wise Open Access Charges Table
- Landed Cost Worked Example
- Captive and Group Captive Treatment
- Banking Charges Under GEOA Regulations 2025
- Commonly Missed Costs
- Application Process and Eligibility
- Frequently Asked Questions
TANGEDCO, TNPDCL, and TNGECL: Entity Guide
Many queries and older documents reference TANGEDCO (Tamil Nadu Generation and Distribution Corporation Ltd.), but this entity no longer exists in its original form. The GoTN demerged TANGEDCO with effect from January 2024:
| Entity | Full Name | Role in Open Access |
|---|---|---|
| TNPDCL | Tamil Nadu Power Distribution Corporation Ltd. | Distribution licensee; administers wheeling, CSS, additional surcharge, and open access applications |
| TNPGCL | Tamil Nadu Power Generation Corporation Ltd. | Conventional (thermal/hydro) generation |
| TNGECL | Tamil Nadu Green Energy Corporation Ltd. | Government RE developer; manages state-owned solar/wind/pumped storage |
| TANTRANSCO | Tamil Nadu Transmission Corporation Ltd. | Intra-state transmission; levies transmission charges |
| TNERC | Tamil Nadu Electricity Regulatory Commission | Regulator; issues tariff and open access orders |
The name change from TANGEDCO to TNPDCL was registered with the Ministry of Corporate Affairs on 27 June 2024 (TNERC Tariff Order No.6 of 2025, para 1.1.10). When applying for open access, all correspondence and applications now go to TNPDCL, not TANGEDCO.
For comparison with Karnataka's open access structure, see our Karnataka open access charges FY2026-27 guide.
What Changed in FY2026-27
TNERC Tariff Order No.6 of 2025 (Effective 1 July 2025)
The most recent published tariff order — TNERC Suo-motu Order No.6 of 2025 dated 30 June 2025 — covers distribution tariff for FY2025-26 (effective 1 July 2025). This is the operative baseline for open access charges until TNERC issues a superseding order. As of 7 October 2026, a separate FY2026-27 tariff order had not been publicly notified; contact TNPDCL to confirm whether an updated order applies.
Additional Surcharge: Pending for H1 and H2 FY2026-27
The additional surcharge under Section 42(4) of the Electricity Act is reviewed every six months:
- Dec 2024 – Mar 2025: ₹0.54/unit (last verified rate)
- Apr 2025 – Sep 2025: TNPDCL proposed ₹0.10/unit; TNERC order status — verify directly
- Oct 2025 – Mar 2026: TNPDCL sought ₹1.14/unit; TNERC had not issued a final order as of mid-2026 due to leadership vacancies in the commission
- FY2026-27 (Apr 2026 – Mar 2027): Rate pending TNERC notification — flag as critical to verify before signing PPAs
This uncertainty in the additional surcharge is the single largest modelling risk for third-party open access projects in Tamil Nadu.
GEOA Regulations 2025: Banking Reform
The TNERC (Terms and Conditions for Green Energy Open Access) Regulations 2025, notified 18 September 2025 and effective 1 October 2025, are now fully operative. Their key changes — 8% in-kind banking charge, monthly settlement, and elimination of banking for third-party OA — are addressed in the banking section below.
15-Minute Block Settlement
All RE generators in Tamil Nadu now operate under 15-minute time-block scheduling and energy accounting, effective for all projects regardless of commissioning date. This increases the operational complexity of open access projects and raises DSM penalty risk for those with variable load profiles.
For a national comparison of open access regimes, see our state-wise open access comparison. For the underlying Green Energy Open Access national framework, see our Green Energy Open Access Rules 2022 explainer.
Voltage-Wise Open Access Charges Table
The table below presents the open access solar charge framework for Tamil Nadu in FY2026-27, based on TNERC Order No.6 of 2025 and GEOA Regulations 2025. Exact rates should be verified with TNPDCL directly.
| Charge Component | HT (11 kV / 22 kV) | EHT (33 kV / 66 kV) | Embedded (Same Substation) | Order Reference |
|---|---|---|---|---|
| Wheeling charges (TNPDCL) | ₹0.45–₹0.55/unit | ₹0.35–₹0.45/unit | ₹0.20–₹0.30/unit | TNERC T.O. No.6/2025 |
| Transmission charges (TANTRANSCO) | ₹0.40–₹0.60/unit | ₹0.40–₹0.60/unit | Nil (same substation) | TANTRANSCO tariff order |
| SLDC scheduling charges | ₹0.05–₹0.10/unit | ₹0.05–₹0.10/unit | ₹0.05–₹0.10/unit | SLDC charge notification |
| Cross-subsidy surcharge (CSS) | ₹1.00–₹1.30/unit (HT-1 Industrial) | ₹1.00–₹1.30/unit | Exempt for captive | TNERC T.O. No.6/2025 |
| CSS (HT-2 Commercial) | ₹1.20–₹1.50/unit | ₹1.20–₹1.50/unit | Exempt for captive | TNERC T.O. No.6/2025 |
| Additional surcharge | ₹0.10–₹0.54/unit (pending H2 FY2027) | Same | Exempt for captive | TNERC half-yearly orders |
| Banking charge (captive/GEOA) | 8% in kind | 8% in kind | 8% in kind | TNERC GEOA Regs 2025 |
| Banking (third-party OA) | Not available | Not available | Not available | TNERC GEOA Regs 2025 |
| Transmission losses | 3–4% in kind | 3–4% in kind | Minimal | TNERC order |
| Distribution / wheeling losses | 5–7% in kind | 4–6% in kind | Minimal | TNERC order |
Note: CSS and additional surcharge are fully exempt for captive generating plants and group captive solar under the Electricity Act 2003, Section 42(2) and related TNERC orders.
Landed Cost Worked Example
The following worked example uses a reference captive generation tariff (levelised cost of energy, LCOE) of ₹2.80/unit and a PPA tariff of ₹3.50/unit for third-party OA, for an HT industrial consumer with monthly consumption of 40,000 units. Grid HT-1 tariff reference: approximately ₹7.50–₹8.50/unit (TNERC T.O. No.6 of 2025).
Captive Open Access — Monthly Cost (40,000 units, HT 11 kV)
| Component | Rate | Monthly Cost |
|---|---|---|
| Solar generation cost (LCOE) | ₹2.80/unit | ₹1,12,000 |
| Wheeling charges (TNPDCL, HT) | ₹0.50/unit | ₹20,000 |
| Transmission charges (TANTRANSCO) | ₹0.50/unit | ₹20,000 |
| SLDC scheduling | ₹0.07/unit | ₹2,800 |
| CSS | Exempt | ₹0 |
| Additional surcharge | Exempt | ₹0 |
| Banking charge (8% in kind, ~400 units lost) | — | ₹1,120 equiv. |
| Losses (~10% combined) | 4,000 units | ₹11,200 equiv. |
| Total delivered cost | ~₹4.17/unit | ~₹1,67,120 |
Assumptions: Captive 26%+ equity structure; LCOE ₹2.80/unit (100 kW captive plant, capex ~₹23,000/kW ex-GST); combined T&D losses 10%; banking charge applied to ~5% of monthly generation.
Third-Party PPA — Monthly Cost (40,000 units, HT 11 kV)
| Component | Rate | Monthly Cost |
|---|---|---|
| PPA tariff | ₹3.50/unit | ₹1,40,000 |
| Wheeling charges (TNPDCL) | ₹0.50/unit | ₹20,000 |
| Transmission charges | ₹0.50/unit | ₹20,000 |
| SLDC scheduling | ₹0.07/unit | ₹2,800 |
| CSS (HT-1 Industrial) | ₹1.15/unit | ₹46,000 |
| Additional surcharge | ₹0.35/unit | ₹14,000 |
| Losses (~10% combined) | 4,000 units | ₹14,000 equiv. |
| Total delivered cost | ~₹6.42/unit | ~₹2,56,800 |
Saving from captive vs third-party PPA: ~₹2.25/unit or ~₹90,000/month for 40,000 units. Annualised: ~₹10.8 lakh/year.
Comparison to grid tariff: At ₹8.00/unit grid HT-1 tariff, captive solar saves ~₹3.83/unit; third-party OA saves ~₹1.58/unit.
Captive and Group Captive Treatment
Captive generating plants hold automatic open access rights under Section 9 of the Electricity Act 2003 and are exempt from CSS and additional surcharge. This is the single largest cost lever available to Tamil Nadu C&I consumers.
Qualifying conditions (Electricity Rules 2005, Rule 3):
- Consumer(s) must hold at least 26% equity in the generating company
- At least 51% of aggregate electricity generated must be consumed captively
- Equity and consumption thresholds are measured on an annual basis
For consumers with contracted demand in the 100 kW–500 kW range where a standalone captive plant is uneconomical, group captive solar allows multiple consumers to hold proportional equity in a shared plant. The CSS exemption saves ₹1.00–₹1.50/unit. For a factory consuming 50,000 units/month, that is ₹50,000–₹75,000/month or ₹6–₹9 lakh/year — often sufficient to justify equity participation.
Banking Charges Under GEOA Regulations 2025
The TNERC (Terms and Conditions for Green Energy Open Access) Regulations 2025 (Notification No. TNERC/GEOA/25-1/2025), notified 18 September 2025 and effective 1 October 2025, introduced a fundamentally new banking regime:
Key changes:
- 8% in-kind banking charge: Applies to all GEOA consumers (captive, group captive) banking surplus RE energy
- Monthly settlement cycle: All banked energy must be utilised within the same billing month; annual banking is abolished
- 75% buyback for unutilised energy: Banked energy not withdrawn by month-end is purchased by TNPDCL at 75% of the applicable RE tariff
- No banking for third-party OA: TPOA consumers must operate on a real-time 15-minute block basis with no banking facility
- Grandfathered exception: Wind projects commissioned before 31 March 2018 continue under a 12-month banking facility at 14% charges
For the national policy context on ISTS transmission waivers affecting open access economics, see our ISTS waiver phaseout guide.
Commonly Missed Costs
Many open access solar cost models underestimate delivered cost by overlooking:
- Reactive energy charges: ₹0.05–₹0.15/unit for poor power factor; manage with capacitor banks
- Deviation Settlement Mechanism (DSM) charges: Penalties for over-injection or under-drawal vs scheduled quantities; elevated under 15-minute block accounting
- Standby charges: Capped at 125% of applicable tariff when grid backup is drawn during solar unavailability
- Meter installation and communication costs: One-time costs for special energy meters and SCADA/communication infrastructure
- Connectivity application fees: Vary by voltage level; confirm with TNPDCL's OA cell
- Annual true-up adjustments: TNERC may revise wheeling or transmission charges mid-year via supplementary orders
These overlooked costs can add ₹0.20–₹0.40/unit to the delivered tariff.
Application Process and Eligibility
Eligibility under TNERC GEOA Regulations 2025:
- HT/EHT consumers with contracted demand ≥ 63 kVA, or industries with connected load ≥ 50 kW
- Application to the nodal agency: TNPDCL's Open Access Cell
- Generator must be an eligible RE source (solar, wind, hybrid, pumped storage)
Application steps:
- Submit open access application to TNPDCL with load details, voltage level, and proposed generator
- TNPDCL to issue connectivity feasibility within 30 days (GEOA Regs 2025, Regulation 9)
- Sign Open Access Agreement with TNPDCL
- Register scheduling data with SLDC-Tamil Nadu
- Commission energy meter with approved metering agency
Long-term open access (>1 year) requires a standing clearance; short-term open access (≤1 month) uses a rolling application. Intra-state RE transactions qualify for concessional charges (wheeling, CSS, additional surcharge) only for power sourced within Tamil Nadu — inter-state or power exchange transactions do not qualify for concessional treatment.
Frequently Asked Questions
What is the cross-subsidy surcharge (CSS) for solar open access in Tamil Nadu?
The cross-subsidy surcharge (CSS) in Tamil Nadu for third-party open access solar is approximately ₹1.00–₹1.30/unit for HT-1 Industrial consumers and ₹1.20–₹1.50/unit for HT-2 Commercial consumers under the TNERC tariff order framework. Captive and group captive consumers are fully exempt from CSS under Section 42(2) of the Electricity Act 2003. This exemption is why captive solar is significantly cheaper than third-party open access in Tamil Nadu. Verify the exact current rate with TNPDCL or the TNERC website before finalising any PPA or financial model.
What is the difference between TANGEDCO, TNPDCL, and TNGECL for open access applications?
TANGEDCO was demerged in January 2024. For open access applications, TNPDCL (Tamil Nadu Power Distribution Corporation Ltd.) is the relevant entity — it is the distribution licensee that administers wheeling charges, CSS, additional surcharge, and open access approvals. TNGECL (Tamil Nadu Green Energy Corporation Ltd.) is the state-owned RE developer. All open access correspondence previously addressed to TANGEDCO should now go to TNPDCL.
What is the additional surcharge for open access in Tamil Nadu in FY2026-27?
The additional surcharge under Section 42(4) of the Electricity Act is reviewed by TNERC every six months. The last confirmed rate was ₹0.54/unit (December 2024 – March 2025). For FY2026-27, TNERC had not published an updated additional surcharge order as of 7 October 2026. The rate is highly variable — TNPDCL has sought anywhere from ₹0.10/unit to ₹1.14/unit in different half-yearly periods. Always verify the current rate with TNERC before financial modelling.
What are the wheeling charges for solar open access in Tamil Nadu?
Wheeling charges (levied by TNPDCL) vary by voltage level. For HT (11 kV/22 kV) connections: approximately ₹0.45–₹0.55/unit. For EHT (33 kV/66 kV) connections: approximately ₹0.35–₹0.45/unit. Embedded generation (generator and consumer on the same substation) pays ₹0.20–₹0.30/unit. These are based on TNERC Order No.6 of 2025 and secondary sources; verify exact current rates with TNPDCL.
Can third-party open access consumers use banking in Tamil Nadu?
No. Under the TNERC GEOA Regulations 2025 (effective 1 October 2025), banking is not available for third-party open access (TPOA) transactions. TPOA consumers must match generation and consumption in real time within 15-minute time blocks. Only captive and group captive consumers may use the banking facility, subject to an 8% in-kind banking charge and monthly settlement.
What is the minimum load for solar open access in Tamil Nadu?
Under the TNERC GEOA Regulations 2025, EHT and HT consumers with contracted demand ≥ 63 kVA are eligible for green energy open access. Industries with connected load ≥ 50 kW may also purchase green power from third-party generators. This lower threshold makes Tamil Nadu relatively accessible compared to states like Maharashtra, where eligibility starts at higher demand levels.
Is captive solar better than third-party open access in Tamil Nadu?
Yes, in almost all cases. Captive solar eliminates CSS (₹1.00–₹1.50/unit) and additional surcharge (₹0.10–₹0.54/unit), and retains banking eligibility. The captive structure reduces landed costs by ₹1.50–₹2.50/unit versus third-party PPA. For a consumer at 40,000 units/month, this is roughly ₹90,000/month or ₹10.8 lakh/year in savings. The trade-off is the requirement to hold ≥26% equity in the generating plant. Group captive arrangements solve this for smaller consumers.
How do Tamil Nadu's open access charges compare to other states?
Tamil Nadu's open access charge burden is among the higher in India, particularly for third-party OA. Captive OA total charges (₹1.40–₹2.00/unit) are broadly comparable to Karnataka (₹1.60–₹2.50/unit) but higher than Rajasthan (₹0.90–₹1.30/unit). Third-party OA charges (₹2.50–₹3.50/unit) are similar to Maharashtra. See our state-wise open access comparison for a full breakdown.
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