Most rooftop solar conversations stall at the same point. The engineering makes sense, the savings are clear, and then someone asks where the capital is coming from. The good news is that paying cash is only one of several ways to own the savings from a solar plant.
The three main models
Capex purchase
You buy the plant outright, own it from day one and keep every taka of savings. It delivers the highest lifetime return and the most control, but ties up capital that might be needed for machinery, expansion or working capital. Payback on a well-sized system is typically four to six years.
RESCO lease
A renewable energy service company finances, builds and maintains the plant on your roof, and you pay a fixed monthly lease. There is little or no upfront cost, and the lease is usually set below the savings so the plant is cash-positive from the first month. Ownership may transfer at the end of the term.
Power purchase agreement (PPA)
The developer owns and operates the plant and sells you the electricity it generates at an agreed per-unit rate, below your grid tariff. You pay only for what is produced, and performance risk sits with the developer.
| Capex | RESCO lease | PPA | |
|---|---|---|---|
| Upfront cost | Full | Low / none | None |
| Monthly payment | None | Fixed lease | Per unit generated |
| Who owns the plant | You | Lessor, then you | Developer |
| Who carries performance risk | You | Shared | Developer |
| Lifetime savings | Highest | Medium | Lowest |
How to choose without stalling
- Start from cash flow, not headline price. Compare net monthly cash position under each model over ten years.
- Be clear about control. If you may sell or move out of the building, a lease or PPA term needs to reflect that.
- Check the accounting treatment with your auditors, as leases and PPAs are treated differently on the balance sheet.
- Ask who maintains the plant, and how performance is guaranteed and measured.
“The expensive option is not capex or lease. It is another year of paying the full tariff while the decision waits.”
What a lessor or developer will ask you for
Lease and PPA providers take on long-term exposure to your site and your business, so expect due diligence. Typical requests include two to three years of audited accounts, twelve months or more of electricity bills, proof of ownership or a long lease on the building, and confirmation that the roof can be accessed for maintenance throughout the contract. Having these ready shortens approval considerably.
We structure all three models, including lease and PPA options through financing partners. A site assessment gives you the system size and savings forecast you need to compare them properly.
Written by
Markets & Policy Desk
Business development, Emerged Power
Tracking tariffs, net-metering rules and power-sector planning so factory owners don't have to.