Akash Hirpara The OPEX model in solar is an arrangement where a developer finances, owns, and maintains a solar plant on a customer's roof or land, and the customer pays a fixed per-kWh tariff under a long-term power purchase agreement. In India it is also called the RESCO model and is common for commercial and industrial rooftop projects.
OPEX vs. CAPEX
| Aspect | OPEX (RESCO) | CAPEX |
|---|---|---|
| Upfront cost | ₹0 | Full system cost |
| Ownership | Developer | Customer |
| O&M | Developer | Customer |
| Tax benefits | Developer | Customer |
| Energy cost | Per-kWh tariff | Variable (after recoup) |
| Best for | C&I with no capital | Owners wanting asset |
How a RESCO/OPEX Deal Is Structured
In practice, the customer signs a long-term PPA (typically 15-25 years) with a RESCO developer, who arranges financing, designs and builds the plant, and stays on as the owner-operator for the life of the contract.
The customer’s only ongoing obligation is to pay for the energy actually consumed, billed monthly at the agreed per-kWh tariff, there’s no loan to service and no O&M team to staff, since both sit with the developer.
Because the tariff (roughly ₹3.50-6.50/kWh in the current Indian C&I market) usually undercuts grid or DISCOM industrial rates, the savings start from month one rather than after a multi-year payback, which is the trade-off CAPEX buyers accept in exchange for eventual full ownership and depreciation benefits.
This is also why OPEX/RESCO structures dominate large commercial and industrial rooftop and open-access deployments in India: a factory or warehouse operator gets clean power without diverting capital from its core business, while the developer monetizes the asset over its operating life.
The one thing an OPEX customer can’t access is the capital subsidy under schemes like CFA, which is tied to system ownership and therefore only flows to CAPEX buyers.
Key Takeaways
- OPEX = zero-CapEx solar via per-kWh tariff PPA.
- Developer owns + operates; customer consumes.
- Tariffs typically ₹3.50-6.50/kWh in India.
- 15-25 year contract term.
- Major segment of Indian C&I solar market.
Related Reading
OPEX/RESCO structuring doesn’t remove the engineering and compliance work, the developer who owns the plant still has to get it designed, permitted, and connected, which is where RESCO developers like Heaven Green Energy and dedicated solar permit design support come in.
For MW-scale rooftop and ground-mount RESCO portfolios spanning multiple sites, the PMC services vs. in-house project management comparison walks through how developers weigh external project management against building an internal team. And because most OPEX deals still route through state DISCOM approval before a plant can be commissioned, the state-wise solar permit processing guide for India is a useful companion for understanding the timelines a RESCO developer is working against.
Disclosure: Heaven Green Energy is a Heaven Designs group company.
Frequently Asked Questions
3 commonly searched questions about OPEX Model (Solar).
How is the OPEX model different from CAPEX?
How long is an OPEX solar contract?
Who maintains the plant in an OPEX model?
Need engineering-backed solar designs?
Heaven Designs prepares solar drawings, structural calculations, electrical engineering documents, and project-specific permit plan sets.