Direct Answer: Tamil Nadu Open Access Solar Charges FY 2026-27
For FY 2026-27, the total landed cost of open access solar in Tamil Nadu ranges from approximately ₹4.00 to ₹4.50 per unit for captive consumers and approximately ₹5.80 to ₹7.00 per unit for third-party open access consumers. The key charges include wheeling charges of ₹0.35 to ₹0.55 per unit (depending on voltage level), cross-subsidy surcharge (CSS) of ₹1.00 to ₹1.50 per unit for third-party OA, additional surcharge of ₹0.10 to ₹0.54 per unit, transmission charges of ₹0.40 to ₹0.60 per unit, and an 8 percent banking charge in kind under the new TNERC Green Energy Open Access Regulations 2025.
The bottom line is that Tamil Nadu's open access solar charges are among the highest in India, but captive and group captive structures can eliminate the CSS and additional surcharge entirely, reducing landed costs by ₹1.50 to ₹2.50 per unit. This makes the group captive model especially attractive for Tamil Nadu-based C and I consumers.
Key Takeaways
- Wheeling charges vary by voltage: HT (11 kV/22 kV) consumers pay ₹0.45 to ₹0.55 per unit; EHT (33 kV/66 kV) consumers pay ₹0.35 to ₹0.45 per unit
- CSS is the biggest cost variable: ₹1.00 to ₹1.50 per unit for third-party OA, but fully exempt for captive and group captive consumers
- Banking regime changed drastically: The TNERC GEOA Regulations 2025 introduced an 8 percent in-kind banking charge with monthly settlement, replacing the previous annual banking facility
- Third-party OA loses banking entirely: Under the 2025 regulations, third-party open access transactions cannot use the banking facility at all
- Additional surcharge is reviewed every 6 months: The most recent verified rate was ₹0.54 per unit (December 2024 to March 2025); TNPDCL sought ₹1.14 per unit for October 2025 to March 2026
- Captive treatment is the biggest lever: Captive consumers save ₹1.50 to ₹2.50 per unit by avoiding CSS and additional surcharge
- 15-minute block settlement: All energy accounting now uses 15-minute time blocks, requiring precise load forecasting
Tamil Nadu Open Access Solar Charges: Voltage-Wise Breakdown
The table below presents the voltage-wise open access solar charge framework for Tamil Nadu in FY 2026-27, based on the latest available TNERC tariff orders and the GEOA Regulations 2025. These rates are drawn from secondary sources referencing TNERC orders; verify exact figures with TNERC or TNPDCL directly before financial modeling.
| Charge Component | HT (11 kV / 22 kV) | EHT (33 kV / 66 kV) | Embedded (Same Substation) | Applicability |
|---|---|---|---|---|
| Wheeling Charges | ₹0.45 to ₹0.55 per unit | ₹0.35 to ₹0.45 per unit | ₹0.20 to ₹0.30 per unit | All OA consumers |
| Transmission Charges (TANTRANSCO) | ₹0.40 to ₹0.60 per unit | ₹0.40 to ₹0.60 per unit | Not applicable (if same substation) | When power crosses distribution circles |
| SLDC Scheduling Charges | ₹0.05 to ₹0.10 per unit | ₹0.05 to ₹0.10 per unit | ₹0.05 to ₹0.10 per unit | All OA transactions |
| Cross-Subsidy Surcharge (CSS) | ₹1.00 to ₹1.50 per unit | ₹1.00 to ₹1.50 per unit | Exempt for captive | Third-party OA only |
| Additional Surcharge | ₹0.10 to ₹0.54 per unit | ₹0.10 to ₹0.54 per unit | Exempt for captive | Third-party OA only |
| Banking Charges | 8 percent in kind | 8 percent in kind | 8 percent in kind | GEOA consumers only (not TPOA) |
| Transmission Losses | 3 to 4 percent | 3 to 4 percent | Minimal | In kind (energy deducted) |
| Distribution Wheeling Losses | 5 to 7 percent | 5 to 7 percent | Minimal | In kind (energy deducted) |
Landed Cost Calculation: Captive vs Third-Party
To summarize, the total landed cost of open access solar in Tamil Nadu depends heavily on whether you use a captive structure or a third-party PPA. The following calculation uses a reference PPA tariff of ₹3.50 per unit and monthly consumption of 40,000 units.
Captive Structure Landed Cost
| Component | Rate | Monthly Cost (40,000 units) |
|---|---|---|
| Solar generation cost | ₹2.80 per unit | ₹1,12,000 |
| Wheeling charges (HT) | ₹0.50 per unit | ₹20,000 |
| Transmission charges | ₹0.50 per unit | ₹20,000 |
| SLDC scheduling | ₹0.07 per unit | ₹2,800 |
| CSS | Exempt | ₹0 |
| Additional surcharge | Exempt | ₹0 |
| Losses (10 percent) | 4,000 units equivalent | ₹11,200 |
| Total delivered cost | ₹4.15 per unit | ₹1,66,000 |
Third-Party PPA Landed Cost
| Component | Rate | Monthly Cost (40,000 units) |
|---|---|---|
| PPA tariff | ₹3.50 per unit | ₹1,40,000 |
| Wheeling charges | ₹0.50 per unit | ₹20,000 |
| Transmission charges | ₹0.50 per unit | ₹20,000 |
| SLDC scheduling | ₹0.07 per unit | ₹2,800 |
| CSS | ₹1.15 per unit | ₹46,000 |
| Additional surcharge | ₹0.35 per unit | ₹14,000 |
| Losses (10 percent) | 4,000 units equivalent | ₹14,000 |
| Total delivered cost | ₹6.42 per unit | ₹2,56,800 |
In short, the captive model delivers a landed cost of approximately ₹4.15 per unit versus ₹6.42 per unit for third-party OA — a difference of ₹2.27 per unit or roughly ₹90,800 per month for a 40,000-unit consumer. This means captive structures are the clear economic choice in Tamil Nadu for consumers who can invest equity in a solar plant.
Voltage-Wise Example: Impact on Landed Cost
The voltage level at which you connect affects both wheeling charges and losses. Here is a comparison across three connection scenarios.
| Parameter | HT (11 kV) Embedded | HT (11 kV) Cross-Circle | EHT (33 kV) Cross-Circle |
|---|---|---|---|
| PPA / Generation tariff | ₹3.50 per unit | ₹3.50 per unit | ₹3.50 per unit |
| Wheeling charge | ₹0.25 per unit | ₹0.50 per unit | ₹0.40 per unit |
| Transmission charge | ₹0 (same substation) | ₹0.50 per unit | ₹0.50 per unit |
| SLDC charge | ₹0.07 per unit | ₹0.07 per unit | ₹0.07 per unit |
| CSS (captive exempt) | ₹0 | ₹0 | ₹0 |
| Additional surcharge (captive exempt) | ₹0 | ₹0 | ₹0 |
| Losses (in kind) | 5 percent | 10 percent | 8 percent |
| Landed cost (captive) | ₹3.94 per unit | ₹4.27 per unit | ₹4.12 per unit |
This means connecting at EHT voltage and keeping the generator and consumer on the same substation (embedded generation) yields the lowest landed cost. The bottom line is that voltage selection and proximity between generation and consumption points can save ₹0.30 to ₹0.50 per unit.
Captive and Group Captive Treatment
Captive generating plants enjoy automatic open access rights under the Electricity Act 2003 and are exempt from both CSS and additional surcharge in Tamil Nadu. This exemption is the single largest cost advantage available to open access solar consumers in the state.
For consumers with demand in the 100 kW to 500 kW range, a standalone captive plant may not be economical. Group captive solar arrangements allow multiple consumers to hold proportional equity in a larger solar plant, accessing economies of scale while retaining the CSS exemption. To qualify as captive, the consumer must hold at least 26 percent equity in the generating plant and consume at least 51 percent of the energy generated for captive use.
To summarize, the CSS exemption saves ₹1.00 to ₹1.50 per unit for captive consumers. For a factory consuming 50,000 units per month, that is ₹50,000 to ₹75,000 per month or ₹6 to ₹9 lakh per year — often enough to justify the equity investment in a solar plant.
Banking Charges Under the New GEOA Regulations 2025
The TNERC Green Energy Open Access Regulations 2025 (Notification No. TNERC/GEOA/25-1/2025), notified on September 18, 2025 and effective from October 1, 2025, introduced a fundamentally new banking regime.
Key Banking Changes
- 8 percent in-kind banking charge: Applies to all GEOA consumers banking surplus solar, wind, or hybrid energy
- Monthly settlement cycle: Eliminates the previously available annual banking facility; all banked energy must be utilized within the same billing month
- 75 percent buyback for unutilized energy: Any banked energy not withdrawn by month-end is purchased by TNPDCL at 75 percent of the applicable RE tariff
- No banking for third-party OA: Third-party open access transactions cannot use the banking facility at all — they must operate on a real-time basis
- 15-minute block settlement: Energy accounting uses 15-minute time blocks for all RE generators, regardless of commissioning date
This means the new banking rules increase the estimated landed tariff by approximately ₹0.05 per kWh for projects that previously enjoyed zero banking charges. The elimination of banking for third-party OA is expected to reduce potential savings and contract sizes by up to 30 percent for TPOA projects, according to industry analysis.
Existing wind projects commissioned before March 31, 2018 continue under a 12-month banking facility at 14 percent charges, providing a grandfathered exception.
Commonly Missed Costs
Many open access solar cost models in Tamil Nadu underestimate the true delivered cost by overlooking several charges.
- Reactive energy charges: Applicable for poor power factor; can add ₹0.05 to ₹0.15 per unit if not managed
- Deviation settlement charges (DSM): Penalties for over-injection or under-drawal against scheduled quantities; particularly significant under 15-minute block accounting
- Standby charges: Capped at 125 percent of the applicable tariff when the consumer draws backup power from the grid during solar unavailability
- Meter installation and communication costs: One-time charges for special energy meters and communication infrastructure
- Connectivity application fees: Vary by voltage level and connection type
- Annual true-up adjustments: TNERC may revise charges mid-year through supplementary orders
The bottom line is that these commonly missed costs can add ₹0.20 to ₹0.40 per unit to the landed cost if not accounted for in the financial model.
Verification Steps for Your Project
Before committing to an open access solar project in Tamil Nadu, follow these verification steps.
- Check the latest TNERC order: Visit tnerc.gov.in for the most recent tariff order and additional surcharge order applicable to your consumption period
- Confirm your voltage category: Wheeling charges differ by voltage level; verify whether your connection is HT (11 kV/22 kV) or EHT (33 kV/66 kV)
- Verify CSS for your consumer category: CSS rates differ for HT-1 (Industrial) versus HT-2 (Commercial); confirm with TNPDCL
- Validate the additional surcharge: This is reviewed every 6 months; check whether a new order has been issued for your project's operational period
- Confirm banking eligibility: Under the 2025 regulations, verify whether your transaction type (captive, group captive, or third-party) qualifies for the banking facility
- Calculate total losses: Include both transmission (3 to 4 percent) and distribution wheeling (5 to 7 percent) losses in your landed cost model
- Model the 15-minute block impact: Assess your load profile against generation profile to estimate unutilized banked energy
Stress-Testing Your Open Access Economics
To summarize, stress-testing your open access solar project in Tamil Nadu requires modeling multiple scenarios.
| Scenario | PPA Tariff | Wheeling | CSS | Additional Surcharge | Banking Impact | Landed Cost |
|---|---|---|---|---|---|---|
| Best case (captive, embedded, low losses) | ₹2.80 | ₹0.25 | ₹0 | ₹0 | Minimal | ₹3.94 per unit |
| Base case (captive, HT cross-circle) | ₹3.50 | ₹0.50 | ₹0 | ₹0 | ₹0.05 | ₹4.27 per unit |
| Worst case (third-party, high CSS, high surcharge) | ₹4.00 | ₹0.55 | ₹1.50 | ₹0.54 | ₹0.10 | ₹7.19 per unit |
This means the spread between best and worst case is approximately ₹3.25 per unit — a 82 percent difference. For a consumer using 1 lakh units per month, that is a swing of ₹3.25 lakh per month or ₹39 lakh per year. Proper structuring (captive vs third-party) and site selection (embedded vs cross-circle) are the most impactful decisions.
For a comprehensive comparison across states, see our solar open access state comparison guide.
Frequently Asked Questions
What is the minimum load requirement for open access solar in Tamil Nadu?
Under the TNERC GEOA Regulations 2025, EHT and HT consumers with a minimum contracted demand of 63 kVA are eligible for green energy open access. Additionally, the regulations state that any industry with a connected load of 50 kW or more can purchase green power from third-party generators. This is a lower threshold than many other states, making Tamil Nadu relatively accessible for smaller C and I consumers. For a broader understanding of open access rules across India, see our open access solar India guide.
How much is the cross-subsidy surcharge (CSS) in Tamil Nadu for FY 2026-27?
The CSS for third-party open access consumers in Tamil Nadu is approximately ₹1.00 to ₹1.30 per unit for HT Industrial (HT-1) consumers and ₹1.20 to ₹1.50 per unit for HT Commercial (HT-2) consumers. Captive and group captive consumers are fully exempt from CSS under the Electricity Act 2003. These rates are based on secondary sources referencing TNERC tariff orders; verify the exact current rate with TNERC or TNPDCL directly.
What is the additional surcharge for open access in Tamil Nadu?
The additional surcharge is reviewed every 6 months by TNERC. The most recent verified rate was ₹0.54 per unit, applicable from December 12, 2024 to March 31, 2025. TNPDCL subsequently proposed ₹0.10 per unit for April to September 2025, and sought ₹1.14 per unit for October 2025 to March 2026. However, TNERC had not issued orders on the ₹1.14 proposal as of mid-2026 due to vacancies in the commission's leadership. Verify the current applicable rate with TNERC directly.
Can I use banking for third-party open access solar in Tamil Nadu?
No. Under the TNERC GEOA Regulations 2025, the banking facility is not available for third-party open access (TPOA) transactions. TPOA consumers must operate on a real-time basis, matching generation and consumption within 15-minute time blocks. This is a critical change that reduces potential savings by up to 30 percent for TPOA projects. Captive and group captive consumers can still use the banking facility with an 8 percent in-kind charge and monthly settlement.
What are the wheeling charges for solar open access in Tamil Nadu?
Wheeling charges vary by voltage level. For HT (11 kV/22 kV) connections, the charge is approximately ₹0.45 to ₹0.55 per unit. For EHT (33 kV/66 kV) connections, it is approximately ₹0.35 to ₹0.45 per unit. Embedded generation (where the generator and consumer are on the same substation) pays ₹0.20 to ₹0.30 per unit. These are based on TNERC tariff orders referenced in secondary sources; confirm exact rates with TNPDCL.
Is captive solar better than third-party open access in Tamil Nadu?
Yes, in most cases. Captive solar eliminates both the CSS (₹1.00 to ₹1.50 per unit) and the additional surcharge (₹0.10 to ₹0.54 per unit), and retains banking eligibility. This saves ₹1.50 to ₹2.50 per unit compared to third-party OA. For consumers who can invest at least 26 percent equity in a solar plant, the captive route is almost always more economical. Learn more about commercial and industrial solar options.
How do Tamil Nadu's open access charges compare to other states?
Tamil Nadu's open access charges are among the higher end nationally. The effective OA charge ranges from ₹1.4 to ₹2.0 per unit for captive consumers and ₹2.5 to ₹3.5 per unit for third-party consumers. This is higher than Rajasthan (₹0.9 to ₹1.3 per unit) and Karnataka (₹1.6 to ₹2.5 per unit) but lower than Maharashtra (₹2.5 to ₹3.5 per unit). See our state comparison guide for a full breakdown.
What is the regulatory framework governing open access solar in Tamil Nadu?
Open access solar in Tamil Nadu is governed by the TNERC (Terms and Conditions for Green Energy Open Access) Regulations, 2025, notified on September 18, 2025 and effective from October 1, 2025. These regulations replaced the earlier framework under the TNERC Grid Connectivity and Intra-State Open Access Regulations, 2014. The 2025 regulations incorporate provisions from the Union power ministry's Electricity (Promoting Renewable Energy through Green Energy Open Access) Rules, 2022, and establish the framework for transmission, wheeling, cross-subsidy, additional surcharges, banking charges, and deviation settlement charges.
How to Get Started with Open Access Solar in Tamil Nadu
- Assess your eligibility: Confirm your contracted demand meets the 63 kVA threshold (HT/EHT) or 50 kW connected load
- Choose your structure: Evaluate captive vs group captive vs third-party based on capital availability and risk appetite — use our solar IRR calculation methodology to model returns
- Identify a solar plant: Find existing plants with available OA capacity or develop a new project with an experienced solar EPC company
- Model the complete cost: Include all charges, losses, banking impact, and commonly missed costs
- Apply for connectivity: Submit applications through TNPDCL or TANGEDCO as applicable
- Register with SLDC: Obtain scheduling ID and install special energy meters
- Monitor TNERC orders: Charges are revised periodically; stay updated via tnerc.gov.in
For consumers exploring whether open access or net metering is the better fit, the key decision factor is your total demand. Consumers under 1 MW should generally consider rooftop net metering, while those above 1 MW should evaluate open access or group captive structures. A qualified solar provider in India can help you navigate this decision.
For understanding the ROI and payback period of your open access solar investment, factor in the full landed cost including all charges discussed above. Alternatively, if you prefer a zero-investment model, explore the RESCO or OPEX solar model which shifts the capital investment to the developer.
Sources
- TNERC GEOA Regulations 2025 — Notification No. TNERC/GEOA/25-1/2025, notified September 18, 2025, effective October 1, 2025: https://solarquarter.com/2025/09/26/tnerc-issues-new-regulations-2025-for-green-energy-open-access-2025-in-tamil-nadu/
- Mercom India — Additional Surcharge for Open Access Power in Tamil Nadu Increased to Rs 0.54/kWh: https://mercomindia.com/additional-surcharge-nadu-increased-to-%E2%82%B90-54-kwh
- Neufin — New TNERC Green Energy Open Access Regulations 2025: Key Takeaways for Businesses: https://neufin.co/blog/tamil-nadu-open-access-regulation-2025-for-business/
- ET EnergyWorld — Tamil Nadu green energy open access rules boost renewable power for industries: https://energy.economictimes.indiatimes.com/news/renewable/tamil-nadu-green-energy-open-access-rules-boost-renewable-power-for-industries/124191449
- New Indian Express — TNPDCL mulls hike in additional surcharge for open access buyers: https://www.newindianexpress.com/states/tamil-nadu/2025/Aug/20/tnpdcl-mulls-hike-in-additional-surcharge-for-open-access-buyers
- The Hindu — TNPDCL proposes to levy additional surcharge of Rs 0.10 per unit: https://www.thehindu.com/news/national/tamil-nadu/tnpdcl-proposes-to-levy-additional-surcharge-of-010-per-unit-on-open-access-power-consumers/article69281582.ece
- Times of India — Debt-ridden TNPDCL lets Rs 584 crore slip: https://timesofindia.indiatimes.com/city/chennai/debt-ridden-tnpdcl-lets-584-crore-slip-another-300-crore-at-risk/articleshow/132544795.cms
- Tristar Energy — Solar Wheeling and Banking Charges in Tamil Nadu 2026: https://www.tristarenergy.in/blog/solar-wheeling-charges-banking-tamil-nadu
- Mercom India — Tamil Nadu Notifies Green Energy Open Access Regulations 2025: https://www.mercomindia.com/tamil-nadu-notifies-green-energy-open-access-regulations-2025
- SurgePV — Tamil Nadu Solar Compliance Guide 2026: https://www.surgepv.com/solar-compliance/india/tamil-nadu
Regulatory status last checked: August 6, 2026. Charges are subject to periodic revision by TNERC. Verify all figures with TNERC (tnerc.gov.in) or TNPDCL directly before financial modeling or project commitment.
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