Quick Facts
What a RESCO is
RESCO stands for Renewable Energy Service Company. A RESCO is a developer that designs, finances, installs, owns, operates, and maintains a renewable energy plant at a customer’s site (or near it), supplying electricity to the customer under a long-term power purchase agreement. The RESCO is the asset owner; the customer is the power purchaser.
The model exists because many potential solar customers cannot or do not want to buy a solar plant outright. RESCOs solve this by providing solar as a service. The customer pays only for the electricity generated, at a contracted per-kWh tariff lower than grid power. No upfront capital outlay from the customer is required.
RESCO is the dominant model for commercial and industrial rooftop solar in India. Estimated 50% to 70% of new C&I rooftop solar installations are RESCO/OPEX, with the rest being CAPEX or hybrid structures.
How a RESCO operates
A RESCO’s business has five key activities.
Customer development: Identifying suitable customers (sufficient rooftop or land, adequate creditworthiness, sufficient electricity consumption). RESCOs invest heavily in business development teams.
Engineering and design: Designing the solar plant for each customer’s specific site, accounting for roof orientation, shading, structural capacity, electrical interface, and net-metering rules.
Financing: Arranging the capital. Major RESCOs use project finance structures with limited recourse, bringing in lenders like IREDA, EXIM Bank, and commercial banks. Equity comes from the RESCO’s balance sheet or external investors.
Construction: Installing the plant. Most RESCOs use EPC contractors for actual construction while overseeing quality.
Operations: Running the plant for the 15 to 25 year PPA term. The RESCO handles all O&M, monitoring, performance issues, and customer billing.
The RESCO earns revenue from the PPA tariff multiplied by energy delivered. The model is capital-intensive, with payback periods of 6 to 12 years for the RESCO depending on tariff levels and financing costs.
RESCO business model economics
For a typical RESCO project:
CAPEX per kWp installed: Rs 47,000 to Rs 55,000 (commercial scale).
Annual O&M cost: Rs 1,500 to Rs 2,500 per kWp.
Project finance: 70% to 75% debt, 25% to 30% equity.
Debt interest rate: 9% to 11% per annum, tenure 12 to 18 years.
Tax benefits: RESCO claims AD (60% in year 1), GST input credit (12% to 18%), and standard depreciation.
PPA tariff: Rs 3.50 to Rs 5.50 per kWh depending on customer profile.
Project IRR (post-tax, equity): 13% to 18%.
PPA term: 15 to 25 years.
The RESCO’s IRR depends heavily on tariff levels, financing costs, and customer credit quality. Strong-credit customers get lower tariffs but the RESCO accepts lower IRR for better risk-adjusted returns.
Key Indian RESCO players in 2026
CleanMax: Founded in 2012, focused exclusively on C&I solar. Largest portfolio in India by some measures. Owned by Brookfield since 2023.
Amplus Solar: Established 2014, acquired by PETRONAS in 2019. Strong C&I rooftop presence.
Fourth Partner Energy: 2010 founding, large rooftop OPEX portfolio. Combined with TPG-backed Norfund investment.
ReNew: Diversified renewable, with rooftop OPEX as one segment. India’s largest pure-play renewable developer.
Tata Power Solar: Tata group’s solar arm, with both EPC and RESCO offerings. Strong residential and commercial presence.
Adani Green: Large utility-scale developer, with growing rooftop OPEX activity.
Hero Future Energies: Diversified, with rooftop and utility activity.
Solarsis: Mid-sized rooftop and commercial OPEX.
Several smaller and regional RESCOs serve specific markets and customer segments.
RESCO contract structure
A standard RESCO PPA includes:
Capacity and configuration: System size in kWp, technology (mono PERC, TOPCon, bifacial), mounting type, inverter selection.
Tariff: Fixed per-kWh price, often with annual escalation of 1% to 3% to absorb O&M cost inflation.
PPA term: Duration, typically 15 to 25 years.
Site access: Terms for the RESCO to install and operate on the customer’s property.
Minimum offtake: Customer’s obligation to consume the energy generated (typically 80% to 90% of expected).
Performance guarantee: Plant availability targets (typically 95% to 98%).
Tariff escalation: Mechanism for annual or biennial tariff adjustment.
Buyout option: Customer’s right to purchase the plant at defined intervals.
Credit security: Bank guarantees, escrow accounts, or letters of credit securing payments.
Force majeure and termination: Standard provisions.
Change in law: Protection for both parties against regulatory changes.
End of PPA: What happens at end of term (transfer to customer, continued operation, removal).
RESCO and DISCOM relationship
The RESCO installs solar at the customer’s site. The DISCOM handles net metering, billing, and grid services for the customer.
Under typical net metering structure: The customer consumes solar generated on-site, with surplus exported to the DISCOM grid for credit. The DISCOM bills the customer for net consumption from the grid.
The customer separately pays the RESCO for the contracted solar electricity (at the PPA tariff, typically based on solar meter readings).
The DISCOM’s role is the same as in CAPEX projects. The difference is the financial and operational structure between customer and RESCO.
RESCO in different scenarios
Single rooftop: A RESCO installs a 200 kW rooftop solar plant at a manufacturing facility. Customer pays Rs 4.50 per kWh for solar generated.
Multi-site portfolio: A retail chain with 50 stores contracts with a RESCO for solar at each location. Aggregated portfolio supplies the chain’s national consumption.
Group housing societies: A RESCO installs a plant on the society’s common area, serving the building’s common facilities and (in some states) selling surplus to individual flats.
Open-access ground-mount: A RESCO builds a 50 MW solar park and signs multiple PPAs with C&I customers for portions of the output, delivered through open access.
Solar plus storage: RESCOs with battery integration provide 24-hour or peak-shaving solar plus storage services to industrial customers.
Common mistakes regarding RESCOs
Choosing RESCOs based on tariff alone without considering financial strength.
Ignoring the buyout option. Future-proofing the contract through a clear buyout mechanism has long-term value.
Forgetting that AD and GST input credit accrue to the RESCO, not the customer. The lower tariff reflects this.
Not negotiating change-in-law and force majeure clauses carefully.
Signing PPAs without clear performance guarantees and remedies.
Overlooking the minimum offtake clause. If the customer’s consumption drops materially, they may be charged for unconsumed energy.
Best practices for customers signing RESCO PPAs
Choose RESCOs with strong financial credentials, operational track record, and Indian after-sales presence.
Insist on ALMM-listed modules, MNRE-empanelled inverters, and IEC-certified components.
Negotiate tariff carefully. Get multiple bids from different RESCOs.
Include buyout option with formulaic pricing.
Include termination rights for breach of performance guarantees.
Verify the RESCO’s compliance with applicable regulatory and ALMM requirements.
For multi-site operations, consider single aggregated RESCO contract for portfolio discount.
Standards and references
RESCO PPAs are governed by the Electricity Act 2003, state SERC net-metering orders, contract law under the Indian Contract Act, and applicable income tax and GST provisions. MNRE has issued model PPAs for various scheme structures. The Solar Power Developers Association (SPDA) and other industry bodies provide guidance documents.
Related glossary terms
- OPEX Model
- CAPEX Model
- Power Purchase Agreement
- Group Captive
- Accelerated Depreciation
- IRR
- Open Access Solar
- DISCOM
Key takeaways
RESCO (Renewable Energy Service Company) is a developer that owns, operates, and maintains a solar plant at a customer’s site under a long-term power purchase agreement. The model is functionally equivalent to OPEX, providing solar as a service with no upfront cost to the customer. Indian RESCO tariffs in 2026 range from Rs 3.50 to Rs 5.50 per kWh, delivering 30% to 50% savings over grid power. Major Indian RESCOs include CleanMax, Amplus, Fourth Partner Energy, ReNew, and Tata Power Solar. The model is dominant for C&I customers without strong tax position or capital availability.