Quick Facts
What Is Open Access?
Open Access is the right of a large electricity consumer to buy power directly from a generator of their choice, using the transmission and distribution networks owned by central, state, or private utilities. The mechanism is established under Section 42 of the Electricity Act 2003 and operationalised through CERC regulations (inter-state open access) and SERC regulations (intra-state open access).
For solar, Open Access enables commercial and industrial (C&I) consumers to procure clean power through long-term contracts with utility-scale solar developers. Instead of buying all their electricity from the local DISCOM, the consumer signs a Power Purchase Agreement with an independent solar developer. The DISCOM continues to provide standby capacity, billing for residual consumption, and grid services, but the bulk of the energy comes from the open-access supplier.
Open Access has become one of India’s largest renewable energy growth drivers. Corporate solar through open access now totals several gigawatts of installed capacity, with new contracts adding 3 to 5 GW annually as of 2026. For industrial consumers in Gujarat paying UGVCL, MGVCL, PGVCL, or DGVCL tariffs of Rs 8 to Rs 12 per kWh, Open Access solar at Rs 4 to Rs 5.5 per kWh delivers immediate and sustained cost reduction.
The Open Access framework creates a competitive market for electricity procurement. Consumers gain price certainty through long-term fixed tariffs. Developers gain offtake certainty for project financing. The grid gains distributed renewable generation. DISCOMs retain grid service revenue while losing only the energy margin.
Open Access transactions flow through the existing grid infrastructure. The consumer does not need a direct physical connection to the solar plant. Instead, the solar generation is injected at the plant location, and an equivalent amount is drawn at the consumer location, with energy accounting managed through banking and settlement mechanisms.
Why Open Access Matters
Open Access matters because it breaks the monopoly of DISCOMs over electricity supply to large consumers, introducing competition that drives down prices and accelerates renewable adoption.
Cost savings: C&I consumers typically save 25% to 45% versus grid tariffs. For a 10 MW equivalent consumption facility, this translates to Rs 3 to Rs 6 crore in annual savings, capital that can be reinvested in core business operations.
Price hedging: Solar PPAs lock in tariffs for 20 to 25 years, while grid tariffs typically rise 3% to 5% annually. Open Access provides long-term price certainty in an inflationary electricity market.
RPO compliance: Power procured from renewable sources through Open Access counts toward the consumer’s Renewable Purchase Obligation. This is mandatory for obligated entities and valuable for voluntary corporate sustainability programs.
Carbon and ESG goals: Open Access solar contracts serve dual purposes of cost reduction and emissions reduction. Large corporations use Open Access to meet Science-Based Targets and RE100 commitments.
Scale economy: Open Access solar plants are typically 10 MW to 200 MW ground-mount installations requiring specialised ground-mount solar design, achieving lower per-Wp CAPEX and tariffs than on-site rooftop installations. A single PPA can supply multiple facilities.
Grid resilience: Diversifying supply sources across geography and technology reduces dependence on a single DISCOM and improves supply reliability.
Important: Heaven Green Energy advises industrial consumers in Gujarat to evaluate Open Access alongside rooftop solar for a hybrid procurement strategy that maximises both savings and energy security.
How Open Access Works
The mechanics of Open Access solar procurement involve five sequential steps.
-
Eligibility assessment: The consumer determines eligibility under the relevant state’s Open Access regulations. Eligibility depends on contract demand or sanctioned load above the state-defined threshold (typically 1 MW or 100 kVA).
-
Developer selection and PPA negotiation: The consumer selects a solar developer and negotiates a long-term PPA, typically 15 to 25 years. Key terms include tariff, escalation (if any), termination clauses, force majeure, and change-in-law protection.
-
Project development: The developer secures land through site survey and land feasibility assessment, evacuation infrastructure, and project financing. The solar plant is constructed and connected to the state or inter-state transmission network.
-
Regulatory approvals: The developer files Open Access applications with SLDCs, DISCOMs, and CERC (inter-state) or SERC (intra-state). Charges, banking arrangements, and metering protocols are finalised.
-
Power delivery and settlement: Power flows from the solar plant to the consumer through the grid. The consumer pays the developer the contracted tariff per kWh and pays the DISCOM applicable Open Access charges. Metering is typically on a 15-minute time block basis, with energy balancing rules defined in regulations.
The consumer’s landed cost equals the PPA tariff plus all Open Access charges: transmission, wheeling, cross-subsidy surcharge, additional surcharge, standby charges, and applicable losses. Even after all charges, the landed cost typically remains 25% to 45% below grid tariffs.
Visual Explanation
Real-World Example
A pharmaceutical manufacturing facility in Ahmedabad, Gujarat, consumed 25 million kWh annually with a contract demand of 4 MVA. Grid tariffs from Torrent Power averaged Rs 9.5 per kWh, yielding an annual electricity cost of Rs 23.75 crore.
The facility signed a 20-year Open Access PPA with a 15 MW solar developer in Kutch at Rs 3.80 per kWh. After adding wheeling charges (Rs 0.80), transmission charges (Rs 0.40), cross-subsidy surcharge (Rs 1.20), and standby charges (Rs 0.30), the all-in landed cost was Rs 6.50 per kWh.
Annual savings: 25 million kWh × (Rs 9.50 - Rs 6.50) = Rs 7.5 crore.
The facility also installed a 2 MW rooftop solar system under net metering, covering an additional 15% of consumption at Rs 4.50 per kWh effective cost (after PM Surya Ghar subsidy). Combined, the facility achieved 65% renewable sourcing and Rs 8.2 crore in annual savings.
The Open Access contract included a change-in-law clause protecting the consumer from regulatory adverse changes. The developer handled all regulatory approvals, with power delivery commencing 9 months after PPA execution.
Technical Specifications / Benchmarks
| Parameter | Typical Range |
|---|---|
| PPA tenure | 10-25 years |
| Solar PPA tariff (2026) | Rs 3.50-5.50/kWh |
| Wheeling charges | Rs 0.30-1.20/kWh |
| Transmission charges (ISTS) | Rs 0.30-1.00/kWh |
| Cross-subsidy surcharge | Rs 0.50-2.50/kWh (state-dependent) |
| Standby charges | Rs 0.20-0.50/kWh |
| Total landed cost | Rs 5.00-7.50/kWh |
| Savings vs grid tariff | 25-45% |
| Approval timeline | 6-12 months |
| Minimum consumer size | 1 MW (varies by state) |
| Banking period | Monthly to annual (state-dependent) |
| State | Solar Tariff (Rs/kWh, all-in) | Effective Discount vs Retail |
|---|---|---|
| Maharashtra | 4.5 to 5.5 | 30% to 40% |
| Karnataka | 4.2 to 5.2 | 25% to 35% |
| Tamil Nadu | 4.5 to 5.8 | 30% to 40% |
| Gujarat | 4.0 to 5.0 | 25% to 35% |
| Andhra Pradesh | 4.0 to 5.0 | 25% to 35% |
| Rajasthan | 3.5 to 4.5 | 30% to 40% |
| Madhya Pradesh | 3.8 to 4.8 | 25% to 35% |
Benefits / Advantages
- Immediate cost reduction: 25% to 45% savings versus grid tariffs improve operating margins from month one.
- Long-term price certainty: Fixed or minimally escalating tariffs hedge against grid tariff inflation of 3% to 5% annually.
- No upfront capital: Open Access is an OPEX model. The consumer pays only for energy consumed, with zero CAPEX for plant construction.
- RPO compliance: Renewable procurement through Open Access satisfies regulatory obligations and voluntary sustainability targets.
- Carbon footprint reduction: Solar power displaces grid coal generation, reducing Scope 2 emissions by 800 to 1,000 g CO2 per kWh.
- Scale flexibility: Single PPA can supply multiple facilities, simplifying procurement for distributed operations.
- Technology risk transfer: The developer owns and operates the plant, bearing technology and performance risks.
- Grid services retained: DISCOM continues providing standby capacity, voltage support, and grid maintenance.
- Hybrid compatibility: Open Access pairs seamlessly with on-site rooftop solar and battery storage for higher renewable share.
- ESG reporting: Long-term renewable PPAs support CDP, GRI, and Science-Based Targets reporting requirements.
Limitations / Drawbacks
- Regulatory complexity: CSS, wheeling, transmission, and standby charges vary by state and can change with SERC orders. Regulatory risk requires active monitoring.
- Developer credit risk: A 25-year PPA is only as strong as the developer’s financial health. Developer default mid-contract creates supply disruption.
- DISCOM resistance: Some states impose procedural delays or additional charges to discourage Open Access and protect DISCOM revenues.
- Standby charges continue: Even with 80% Open Access coverage, standby capacity charges for grid backup remain payable.
- Deviation settlement costs: Solar output variability creates imbalances versus scheduled consumption. Imbalance charges apply under the deviation settlement mechanism.
- Long-term commitment: Early PPA termination typically involves substantial exit penalties, reducing flexibility.
- Not available to small consumers: Thresholds of 1 MW or 100 kVA sanctioned load exclude most SMEs and residential consumers.
- Inter-state barriers: Some states discourage inter-state Open Access through high additional surcharges or restrictive banking rules.
Comparison Section
| Feature | Open Access | Group Captive | Rooftop Solar | DISCOM Supply |
|---|---|---|---|---|
| Equity requirement | None | 26% minimum | 100% (owner) | None |
| Upfront capital | Zero | Partial | Full | Zero |
| CSS applicability | Yes | Generally exempt | N/A | N/A |
| PPA tenure | 10-25 years | 10-25 years | 25 years | Monthly |
| Savings vs grid | 25-45% | 35-50% | 50-70% | 0% |
| Scale | 10-200 MW | 10-200 MW | 1 kW-10 MW | Unlimited |
| RPO compliance | Yes | Yes | Yes | Only if green tariff |
| O&M responsibility | Developer | Developer/Consumer | Owner/EPC | DISCOM |
| Best for | Low-CSS states | High-CSS states | On-site generation | Baseline supply |
Applications
- Large manufacturing: Textile, pharmaceutical, chemical, and automotive plants with 5 MW+ consumption benefit from scale economies in Open Access solar.
- IT campuses and data centres: 24/7 operations with high load factors maximise solar capacity utilisation and savings.
- Shopping malls and hospitals: Large commercial complexes with consistent daytime loads match solar generation profiles.
- Industrial parks: SEZs and industrial estates aggregate multiple consumers for collective Open Access procurement.
- Educational institutions: Universities and colleges with large campuses use Open Access for cost reduction and sustainability credentials.
- Cold storage and warehousing: Refrigeration loads with high consumption benefit from long-term price hedging.
- Multi-location corporates: Single Open Access PPA can supply geographically distributed facilities through the national grid.
Industry Standards & Regulations
Open Access is governed by a layered regulatory framework:
- Electricity Act 2003, Section 42: Establishes the statutory right of consumers to Open Access.
- CERC Open Access Regulations: Governs inter-state Open Access, including ISTS charges, scheduling, and settlement.
- State SERC Regulations: Each state’s electricity regulatory commission defines intra-state Open Access rules, eligibility thresholds, charges, and procedures.
- National Tariff Policy: Provides overarching policy direction for Open Access, including provisions for non-discriminatory treatment.
- Ministry of Power Notifications: Periodic clarifications and amendments, including the ISTS charges waiver for renewable generators.
- Grid Code Compliance: Open Access consumers and generators must comply with state and central grid codes for scheduling, metering, and safety.
- CERC (Terms and Conditions for Tariff) Regulations: Determines transmission and wheeling charge methodologies.
India-Specific Context
India’s Open Access market has evolved from limited pilot projects to a mainstream procurement channel for C&I renewable energy.
Market growth: Open Access solar capacity has grown from under 1 GW in 2018 to over 15 GW in 2026. Corporate PPAs from Open Access now represent 40% of new C&I solar capacity additions.
State leadership: Gujarat, Maharashtra, Karnataka, Tamil Nadu, and Rajasthan are the most active Open Access markets. Gujarat’s industrial density and supportive regulatory environment make it particularly attractive. The state’s four DISCOMs (UGVCL, MGVCL, PGVCL, DGVCL) have well-established Open Access procedures.
ISTS waiver impact: The Government of India’s waiver of ISTS transmission charges for solar and wind generators (extended through 2025 and beyond) significantly improved the economics of intra-state versus inter-state Open Access. Projects in Rajasthan and Gujarat can now supply consumers in Maharashtra and Karnataka at competitive landed costs.
DISCOM revenue concerns: Some states (Punjab, Haryana) have applied temporary restrictions on Open Access citing revenue protection. CERC and APTEL have consistently upheld consumer rights to Open Access under the Electricity Act.
Group captive preference: In states with high CSS (Tamil Nadu, Andhra Pradesh), group captive structures are preferred over pure Open Access. Consumers accept equity participation to avoid the CSS burden.
Gujarat advantage: Gujarat combines low CSS, supportive SERC (GERC), strong solar irradiance, and established developer ecosystems. Industrial consumers in Surat, Vadodara, Ahmedabad, and Rajkot actively procure Open Access solar.
Future Trends
The Open Access landscape is evolving through regulatory, technological, and market developments.
Green Open Access Rules 2022: The Ministry of Power’s Green Open Access Rules standardise eligibility (100 kW and above), streamline approval timelines, and mandate uniform charges. Implementation is improving state-by-state consistency.
Hybrid and RTC contracts: Corporate buyers increasingly demand round-the-clock (RTC) renewable supply. Hybrid solar-wind-battery projects under Open Access are emerging to meet this demand, though at higher tariffs than solar-only.
Peer-to-peer trading: Pilot projects in select states enable direct bilateral trading between prosumers and consumers within the distribution network, potentially reducing Open Access charges.
Virtual PPAs: Financial contracts without physical power delivery are gaining interest among corporates seeking renewable attributes without operational complexity.
Battery integration: Falling battery costs enable solar-plus-storage Open Access contracts using hybrid inverter systems for evening peak discharge, improving capacity utilisation and grid value.
Carbon markets: International voluntary carbon markets may provide additional revenue streams for Open Access solar projects, reducing consumer tariffs further.
Consolidation: The developer market is consolidating around large players with strong balance sheets and multi-state regulatory expertise. Smaller developers face financing challenges for long-term PPAs.
Common Mistakes & Misconceptions
- Underestimating regulatory complexity: CSS, wheeling, transmission, and standby charges vary by state and can change with SERC orders. A static financial model quickly becomes obsolete.
- Choosing lowest PPA tariff without analysing landed cost: The PPA tariff is only one component. A low PPA with high wheeling charges can be more expensive than a higher PPA with low charges.
- Ignoring developer financial strength: A developer default in year 5 of a 25-year contract creates serious supply and legal complications. Credit due diligence is essential.
- Forgetting standby capacity costs: Even with Open Access covering 80% of load, DISCOM standby charges continue. Total savings must include this residual cost.
- Ignoring grid imbalance charges: Solar output varies; consumer demand varies. Deviations from scheduled injection/consumption attract imbalance charges under DSM regulations.
- Not considering hybrid solar plus wind plus battery: Solar-only Open Access provides daytime generation only. For higher renewable share and evening coverage, hybrid structures are necessary.
- Overlooking change-in-law clauses: Regulatory changes can increase charges or restrict Open Access. Robust PPAs include change-in-law protection.
- Assuming Open Access is available everywhere: Eligibility thresholds, charges, and DISCOM cooperation vary dramatically by state. What works in Gujarat may not work in Bihar.
- Neglecting RPO accounting: Consumers must ensure Open Access renewable procurement is properly credited against their RPO obligations through state energy department registration.
- Confusing Open Access with net metering: Open Access is for large consumers procuring from remote generators. Net metering is for on-site generation. They are complementary, not competing, mechanisms.
Key Takeaways
- Open Access allows large electricity consumers in India to buy power directly from generators using the transmission and distribution network.
- For solar, Open Access is the primary mechanism by which C&I consumers source long-term clean power at fixed tariffs, typically saving 25% to 45% versus grid rates.
- Charges include transmission, wheeling, cross-subsidy surcharge, and standby; net savings remain substantial after all charges.
- The mechanism is regulated by CERC for inter-state and SERCs for intra-state, with policies that vary across states and continue to evolve.
- Group captive is an alternative for consumers in high-CSS states, requiring 26% equity but avoiding cross-subsidy surcharge.
- Green Open Access Rules 2022 are standardising eligibility and streamlining approvals across states.
- Heaven Green Energy advises Gujarat industrial consumers to evaluate Open Access alongside rooftop solar for maximum savings and energy security.
- Developer creditworthiness, landed cost analysis, and regulatory monitoring are critical success factors for Open Access procurement.
- Hybrid solar-wind-battery Open Access contracts are emerging to meet corporate demand for round-the-clock renewable supply.
- Open Access and net metering are complementary; combining both maximises renewable share and cost reduction.
Related Glossary Terms
- Power Purchase Agreement
- Renewable Energy Certificate
- Renewable Purchase Obligation
- Group Captive Model
- Wheeling Charges
- Cross-Subsidy Surcharge
- DISCOM
- ISTS Charges
- CERC
- SERC
- Net Metering
- Feed-in Tariff
- Time of Day Tariff
- Deviation Settlement Mechanism
Related Resources
- Commercial Solar, C&I solar solutions with Open Access advisory
- Industrial Solar, 100 kW to 1 MW+ industrial solar with hybrid procurement strategies
- Ground Mount Solar Park, Utility-scale solar development for Open Access supply
- Solar Calculator, Calculate Open Access savings versus grid tariffs
- OPEX vs CAPEX Solar, Understanding zero-capex Open Access models
- Accelerated Depreciation for Solar, Tax benefits for solar investments
- GST on Solar, Tax implications for Open Access and rooftop solar
- Net Metering in India, Combining on-site generation with Open Access procurement
- PM KUSUM Complete Guide, Agricultural solar and Open Access for rural consumers
- Solar for Textile Industry, Industry-specific solar and Open Access case studies
Sources & References
- Electricity Act 2003, Section 42 (Open Access)
- CERC (Open Access in Inter-State Transmission) Regulations, 2008 and amendments
- Ministry of Power, Green Open Access Rules, 2022
- GERC (Gujarat Electricity Regulatory Commission) Open Access Regulations
- MSEDCL Open Access Procedures and Charges Schedule
- Ministry of Power Notification on Waiver of ISTS Charges for Renewable Generators
- Bridge to India, India Open Access Market Report 2025
- CRISIL, Corporate Renewable Procurement Trends 2025
- Heaven Green Energy internal market analysis (Gujarat C&I solar procurement)