Quick Facts
What Turnkey EPC is
Turnkey EPC (Engineering, Procurement, and Construction) is a project delivery model where a single contractor takes responsibility for the entire solar plant development, from initial design through to commissioning. The customer effectively “turns the key” to start a fully operational plant. The turnkey model contrasts with separate-contract approaches where the customer manages multiple contractors for different aspects of the project.
For Indian solar projects, turnkey EPC is the dominant delivery method, accounting for the majority of utility-scale and commercial installations. The model offers significant advantages: single accountability, simplified project management, predictable cost, and faster delivery.
For residential rooftop solar, while the specific “turnkey EPC” terminology is less common, the delivery model is essentially turnkey: the vendor handles design, procurement, installation, and commissioning. The customer just provides the site and pays.
Scope of turnkey EPC
Standard turnkey EPC scope includes:
Engineering:
Site survey and shading analysis.
System design (panel layout, electrical design).
Civil engineering (mounting structures, foundations).
Electrical engineering (cables, switchgear).
DISCOM coordination for grid interconnection.
Single-Line Diagram (SLD) preparation.
Permitting and approvals.
Procurement:
Solar modules (ALMM-listed).
Inverters (MNRE-empanelled).
Mounting structures.
Cables and connectors.
Switchgear and protection devices.
Junction boxes, SCBs, ACDBs, DCDBs.
Transformers (for HT systems).
Monitoring and SCADA equipment.
Construction:
Civil works (foundations, walkways, fencing).
Mounting structure installation.
Module installation.
Electrical wiring (DC and AC).
Switchgear installation.
Earthing and lightning protection.
DISCOM connection.
Testing and Commissioning:
Pre-commissioning checks.
System testing.
Commissioning per DISCOM requirements.
Performance demonstration.
Handover documentation.
Handover:
Plant in operational condition.
As-built drawings.
Warranties package.
Training for plant operators.
Documentation for future operations.
The exact scope is specified in the contract. Most turnkey contracts cover everything from concept to operations, with the customer responsible only for site access, basic infrastructure, and post-commissioning operations.
Benefits of turnkey EPC
Single accountability: Customer has one party to hold responsible. No finger-pointing between contractors.
Predictable cost: Fixed-price contract (or with limited variations). Customer knows the total cost upfront.
Simplified management: Customer’s project management effort is much lower.
Established quality: Experienced EPC contractors deliver known quality.
Faster delivery: Single contractor can move faster than multi-contractor coordination.
Risk transfer: EPC takes design, procurement, construction risks.
Insurance: Insurance coverage from one contractor.
Comprehensive warranty: Single warranty package.
These benefits make turnkey the preferred delivery model for most Indian solar projects.
Turnkey EPC pricing
For utility-scale solar in India:
Standard turnkey CAPEX: Rs 4 to Rs 5 crore per MW.
This includes everything from modules to commissioning.
Breakdown typical: 50-55% modules, 7-10% inverters, 25-35% BOS, 5-10% EPC services.
For rooftop solar:
Residential 5 kW: Rs 2.5 to 3 lakh after subsidy.
Commercial 100 kW: Rs 45-55 lakh.
Commercial 500 kW: Rs 2.2 to 2.6 crore.
Pricing models:
Fixed price (most common): EPC accepts price risk.
Lump-sum: All-inclusive amount.
Per-MW or per-Wp: Sometimes used for clarity.
Variable additions for specific items: Some contracts allow add-ons.
For lender-grade projects, fixed-price turnkey is preferred as it reduces overrun risk for lenders.
Turnkey EPC contract structure
Standard turnkey EPC contract elements:
Scope of Work: Detailed specifications.
Commercial Terms: Total contract value, payment milestones.
Schedule: Project timeline with key milestones.
Performance Guarantees: Plant output guarantees (PR, availability, capacity).
Liquidated Damages: Penalties for delays or underperformance.
Warranty: Component and workmanship warranties.
Insurance: Required coverage.
Variations: Process for scope changes.
Termination: Conditions for early termination.
Dispute Resolution: Arbitration mechanism.
For utility-scale projects, contracts run 100-300 pages with detailed provisions. For smaller commercial, contracts are shorter but still comprehensive.
Key turnkey EPC players in India
For utility-scale solar:
Sterling and Wilson Solar.
Tata Power Solar EPC.
Adani Solar EPC.
Sun Power Renewable.
Mahindra Susten.
Mytrah Solar.
Vikram Solar EPC.
IBC Solar.
CleanMax EPC.
For commercial and industrial solar (100 kW to 5 MW):
Multiple mid-sized EPCs across India.
State-specific EPCs.
Vendor empanelment varies.
For residential rooftop:
Hundreds of empanelled vendors per state.
Verified through PM Surya Ghar portal.
State-specific empanelment lists.
Common turnkey EPC mistakes
Choosing on price alone. Lower price often means quality compromises.
Inadequate due diligence on EPC. Financial strength, track record, technical capability all matter.
Poorly specified contracts. Detailed scope and clear deliverables prevent disputes.
Insufficient performance guarantees. Strong guarantees protect against underperformance.
Skipping bank guarantees and insurance. Risk protection essential.
Missing handover documentation. As-built drawings and operating manuals critical.
Best practices
For customers:
Engage experienced solar lawyers for contract drafting.
Verify EPC’s financial strength and track record.
Specify clear performance guarantees with LD provisions.
Include comprehensive testing and acceptance procedures.
Define dispute resolution mechanism clearly.
Maintain proper documentation throughout.
For EPC contractors:
Build track record progressively.
Maintain quality systems and certifications.
Manage subcontractors carefully.
Build financial strength for guarantees.
Invest in trained staff and equipment.
Standards and references
Turnkey EPC contracts often reference FIDIC templates (international) or NABCB guidelines (India). Specific industry conventions in solar. Indian Contract Act 1872 governs contract enforceability.
Related glossary terms
- Bankable EPC
- ISO 9001 in Solar EPC
- Balance of System
- Solar Financial Closure
- Power Purchase Agreement
Key takeaways
Turnkey EPC (Engineering, Procurement, and Construction) is the project delivery model where a single contractor delivers a fully functional solar plant from concept to operations. The customer “turns the key” to start a working plant. Turnkey covers design, procurement, construction, testing, and commissioning under one contract. For Indian solar, turnkey is the dominant delivery model accounting for most utility-scale and commercial installations. Benefits include single accountability, predictable cost, simplified management, and faster delivery. Standard utility-scale turnkey cost: Rs 4-5 crore per MW. For long-term success, customer due diligence on EPC contractor’s financial strength, track record, and technical capability is essential.