Green Energy Open Access (GEOA) has become one of the most practical ways for commercial and industrial consumers in India to reduce power costs, meet sustainability targets, and move toward clean energy. With policy support from the Ministry of Power and regulations from the Central Electricity Regulatory Commission, many consumers are now sourcing renewable power across state borders.
Inter-State Green Energy Open Access Cost Calculator
• ISTS waiver assumed for eligible renewable projects.
• Charges vary by state and voltage level.
• This calculator is for representation and estimation only.
This detailed blog explains how to calculate Green Energy Open Access charges for inter-state electricity procurement using a real-world scenario:
A 100 MW connected load consumer in Uttar Pradesh sourcing renewable energy from Gujarat.
Understanding the Scenario
Let us assume the following:
- Source State: Gujarat
- Consumer State: Uttar Pradesh
- Connected Load: 100 MW
- Monthly Energy Procurement: 3,00,000 units
- PPA Tariff: ₹3.40 per kWh
- Renewable Source: Solar
- Inter-State Green Open Access
- Commercial and Industrial consumer category
Why Inter-State Green Open Access is Popular
Inter-state procurement allows industries to:
- Access cheaper renewable energy from high-resource states like Gujarat and Rajasthan
- Achieve ESG and sustainability goals
- Hedge against rising DISCOM tariffs
- Secure long-term price stability
- Meet RE100 commitments
With transmission waivers and improved scheduling through national grid platforms such as Power System Operation Corporation, inter-state renewable procurement is becoming increasingly viable.
Step 1: Power Purchase Agreement (PPA) Cost
The first and most important component is the renewable generation cost agreed between the consumer and the developer.
In this case:
- PPA tariff = ₹3.40 per kWh
- Monthly scheduled energy = 3,00,000 units
This cost remains fixed for the tenure of the contract and forms the base for the total landed cost.
Step 2: Inter-State Transmission System (ISTS) Charges
The Government of India provides ISTS charge waivers for renewable energy projects commissioned within defined timelines.
If the Gujarat solar plant qualifies for the ISTS waiver:
- ISTS transmission charges = Zero
This waiver is one of the biggest drivers of cost competitiveness.
If not waived, ISTS typically ranges from ₹0.10 to ₹0.50 per kWh.
Step 3: Inter-State Transmission Losses
Energy losses occur when power is transmitted across long distances. These are notified periodically by national grid operators.
Typical ISTS loss range:
- 2% to 4%
Assuming:
- ISTS loss = 3%
Delivered energy becomes:
- 3,00,000 × (1 – 0.03)
- Delivered = 2,91,000 units
This is the actual usable energy received in Uttar Pradesh.
Step 4: State Transmission Charges in Uttar Pradesh
After reaching the state boundary, the electricity moves through the state network.
Typical charges in many states:
- ₹0.20 to ₹0.60 per kWh
Assuming:
- ₹0.30 per kWh
Step 5: Wheeling Charges
These charges are for using the local distribution network.
Typical range:
- ₹0.30 to ₹1.50 per kWh depending on voltage and consumer category.
Assuming:
- ₹0.70 per kWh
Higher voltage consumers usually pay lower wheeling charges.
Step 6: Cross Subsidy Surcharge (CSS)
CSS is a major component for third-party open access consumers. It compensates DISCOMs for revenue loss.
General formula:
CSS = Tariff payable to DISCOM – Cost of supply – Network charges – Loss adjustment.
For green power, many states are reducing CSS, but it is still applicable.
Assuming:
- CSS = ₹2.00 per kWh
Step 7: Additional Surcharge
This applies when DISCOM assets become under-utilized due to open access.
Typical range:
- ₹0.30 to ₹1.50 per kWh.
Assuming:
- ₹0.50 per kWh
In some states, green energy projects receive partial or full waiver.
Step 8: Scheduling and System Operation Charges
Charges payable to grid operators for scheduling, metering, and system balancing.
Typical range:
- ₹0.02 to ₹0.10 per kWh.
Assuming:
- ₹0.05 per kWh.
Step 9: Banking Charges (if applicable)
Banking allows energy adjustment across months.
Typical:
- 2% to 10% energy.
For simplicity, this example assumes no banking.
Important Disclaimer
This calculation example is only for representation and educational purposes. Actual Green Energy Open Access charges vary based on regulatory approvals, state policies, voltage levels, project eligibility, and periodic tariff revisions.
Step-by-Step Cost Calculation Example
Delivered Energy
Scheduled energy = 3,00,000 units
After ISTS loss of 3%:
Delivered energy = 2,91,000 units
Landed Cost Components
| Component | Cost (₹/kWh) |
|---|---|
| PPA Tariff | 3.40 |
| State Transmission | 0.30 |
| Wheeling | 0.70 |
| CSS | 2.00 |
| Additional Surcharge | 0.50 |
| SLDC & Scheduling | 0.05 |
Total Landed Cost = ₹6.95 per kWh
Monthly Power Cost
2,91,000 × 6.95
= ₹20.22 lakh approximately.
Step 10: Compare with Uttar Pradesh DISCOM Tariff
If the consumer tariff from the DISCOM is:
- ₹9 to ₹10 per kWh → Green open access is highly viable.
- ₹7 to ₹8 → Captive structure or hybrid model may be better.
Key Strategies to Reduce Green Open Access Cost
- ISTS waiver eligibility
- Captive solar or wind structure
- Hybrid renewable procurement
- Storage integration
- High voltage connectivity
- Corporate PPA aggregation
- Load factor optimization
- Long-term contracts
- Time-of-day optimization
- Green hydrogen or manufacturing incentives
Future Trends in Inter-State Renewable Procurement
India is rapidly moving toward large-scale renewable procurement with:
- Solar and wind hybrid projects
- Firm and dispatchable renewable power
- Energy storage integration
- Virtual and financial PPAs
- Corporate decarbonization
Platforms such as Indian Energy Exchange are also enabling flexible renewable procurement.
Conclusion
For a 100 MW connected load consumer in Uttar Pradesh, sourcing renewable energy from Gujarat at ₹3.40 per kWh can deliver significant cost savings while meeting sustainability goals. With ISTS waivers and favorable regulatory support, inter-state green open access is expected to become one of the dominant power procurement models in India.
