CAPEX vs RESCO Solar in India: Which Model Is Better for Businesses?

A business decides to install rooftop solar. The next question often sounds simple: Should we buy the solar plant ourselves—or let somebody else invest and simply buy the electricity? That is essentially the difference between the CAPEX and RESCO models.

The question has become especially relevant after the Municipal Corporation of Delhi approved a unified rooftop-solar programme covering approximately 1,100 civic buildings. Larger systems are expected to use the Renewable Energy Service Company, or RESCO, model, allowing solar deployment without direct upfront capital expenditure by the civic body.

But zero upfront investment does not automatically mean better economics. CAPEX and RESCO transfer different combinations of ownership, financing, operating responsibility, performance risk and long-term value. The correct choice depends on the consumer.

What Is CAPEX Solar?

Under the CAPEX model, the consumer purchases the solar system and normally pays for engineering, modules and inverters, structures, electrical equipment, installation, approvals, insurance where applicable and ongoing O&M. The solar plant becomes an asset of the consumer.

What Is RESCO Solar?

Under a typical RESCO arrangement, a third-party developer finances, installs, owns and operates the solar plant. The consumer provides suitable rooftop or site access and purchases solar electricity under a long-term agreement. The structure converts a capital investment into a long-term electricity-purchase commitment.

Why Zero Investment Solar Needs Careful Language

RESCO is frequently marketed as free solar. That description is misleading. The consumer may avoid upfront capital expenditure, but still pays for solar electricity through the contractual tariff. A better description is third-party-financed solar.

CAPEX vs RESCO: Where Does the Value Go?

Under CAPEX, the owner provides capital and carries ownership risk but keeps the long-term generation value. Under RESCO, the developer provides capital and takes substantial asset-performance responsibility but receives the contracted solar revenue. CAPEX can offer greater lifetime savings; RESCO can preserve the consumer's capital. Neither is universally superior.

When CAPEX Can Be Stronger

CAPEX deserves serious consideration when capital is available, financing is reasonably priced, the property is controlled for the long term, electricity consumption is stable, the business wants maximum long-term savings and professional O&M can be arranged. Post-payback generation is one of CAPEX's major advantages.

When RESCO Can Be Stronger

RESCO can be attractive when an organisation wants to preserve capital, has a large suitable roof and predictable long-term demand, prefers operating expense to capital investment, and can make a sufficiently long and bankable electricity-purchase commitment.

RESCO Has a Major Constraint: Bankability

The developer is investing money on somebody else's premises, so it needs confidence that the consumer will continue buying electricity and paying invoices for many years. RESCO providers may examine consumer credit quality, audited financials, payment history, electricity consumption, property ownership, roof rights, business stability and long-term demand. RESCO is an infrastructure-financing transaction, not simply an EPC quotation with the upfront price removed.

Roof Ownership Can Become Critical

For leased premises, contract duration and roof rights matter. Agreements need clarity on landlord consent, roof access, structural repairs, redevelopment, relocation, early termination and system removal.

Compare Electricity Tariffs Correctly

A business should look beyond the first-year PPA tariff and consider escalation, future grid-tariff assumptions, minimum offtake obligations, deemed generation provisions, taxes and duties, metering, payment security, contract tenure, termination payments and treatment of surplus generation. The lowest headline tariff is not automatically the best contract.

O&M Is One of RESCO's Genuine Advantages

A properly structured RESCO contract aligns part of the developer's revenue with electricity generation. Consumers should still define who cleans modules, replaces failed inverters, pays for insurance, handles major weather events, monitors performance, maintains the roof and pays if the plant must be removed temporarily.

CAPEX Does Not Mean Managing O&M Yourself

A consumer can own the asset while outsourcing O&M, monitoring, diagnostics, insurance support and corrective maintenance. This can combine CAPEX economics with professional asset management.

What About Solar Loans?

Financed CAPEX sits between the two extremes. The business owns the solar system but funds some or most of the investment through debt. The correct comparison may therefore be Cash CAPEX vs Financed CAPEX vs RESCO.

A Simple Decision Framework

Choose CAPEX more seriously when

Capital is available, the roof is controlled long term, electricity demand is stable and the business wants to maximise lifetime savings.

Choose financed CAPEX more seriously when

The business wants ownership but prefers to spread the capital cost over time.

Choose RESCO more seriously when

Capital preservation is more important than owning the solar asset and the organisation can make a long-term contractual commitment.

Five Questions Before Signing a RESCO PPA

Ask: What is the effective tariff over the entire contract after escalation? What happens if consumption falls? Who carries generation and equipment-performance risk? What happens if the roof requires major repair or the facility relocates? What is the exit, buyout or termination mechanism? These questions can matter more than a small difference in starting tariff.

Lessons from Delhi for Rajasthan Businesses

Delhi's model should not be copied blindly into Rajasthan because electricity regulations, incentives and implementation frameworks differ. But the financing lesson is transferable: organisations can use different structures across different properties. Some rooftops may suit CAPEX, others RESCO, and some facilities may require a different renewable-energy strategy.

Key Takeaways

CAPEX generally requires more upfront capital but can provide greater long-term ownership value. RESCO can remove much of the upfront investment but creates a long-term contractual electricity-purchase obligation. Financed CAPEX is a third alternative. Roof tenure, creditworthiness, O&M responsibility, insurance and exit clauses matter. Compare lifetime cash flows rather than only upfront cost or first-year tariff.

Frequently Asked Questions

Is RESCO solar really zero-cost?

It can involve little or no upfront solar capital investment by the consumer, but the consumer pays for electricity under the contractual arrangement. It is better described as third-party-financed solar than free solar.

Who owns the solar plant under RESCO?

Typically, the RESCO developer or project entity owns the system during the contracted period, subject to the specific agreement.

Which gives higher savings: CAPEX or RESCO?

CAPEX can potentially provide greater lifetime savings because the consumer owns the asset, but actual economics depend on financing cost, generation, O&M, tariffs and project performance.

Who maintains a RESCO solar plant?

Normally the developer carries substantial O&M responsibility, but the exact division of responsibilities must be verified in the contract.

Can a factory use a solar loan instead of RESCO?

Yes. Financed CAPEX can allow the factory to own the system while spreading the investment over time.

Is RESCO suitable for leased buildings?

It can be more complicated. Lease duration, landlord consent, roof rights, relocation and early-termination provisions become particularly important.

Wattscore Perspective

The financing model should be selected only after the solar system itself has been designed around the consumer's load, roof and electricity economics. Wattscore can evaluate rooftop potential, consumption patterns, CAPEX economics, financing, O&M requirements and alternative renewable-energy structures before a business commits to a long-term solar investment.