In one line
With no capital to commit and no appetite for risk, the roof lease model is usually the better fit; with heavy electricity use and the capacity to carry an investment until it pays back, the owner-invested model usually is — and the choice should be settled by comparing the 20-year cash flow of both structures.
How the two structures differ
In the roof lease model you rent out the roof and collect rent. The developer installs and owns the system and carries the operating responsibility. The building owner invests nothing and receives a set rent for the term of the contract.
In the owner-invested model the building owner installs and owns the system. Power used on site cuts the electricity bill, and anything left over can be sold. In exchange, the owner carries the upfront cost and the operating responsibility.
| Item | Roof lease | Owner-invested |
|---|---|---|
| Upfront investment | None | Required (financing and government support programs can be used) |
| Form of return | Contracted rent | Lower electricity bills, plus sales of surplus power |
| Ownership of the system | Developer | Building owner |
| Operation and maintenance | Developer | Building owner (O&M can be outsourced) |
| Variability of return | Low (fixed rent) | Yes (it moves with energy yield, tariffs, and prices) |
| Use toward RE100 | Limited (depends on contract terms) | Available (self-consumption counts) |
| At the end of the contract | System removed, or transfer negotiated | The system stays with the building owner |
Swipe the table sideways to see the rest
It comes down to how much power you use
The main return in the owner-invested model is the bill you no longer pay. The more of your own generation you consume where it is produced, the better it gets. If the factory barely runs during daylight hours, that power has to be sold instead — and then the sale price sets the return, which narrows the gap with a roof lease.
- Heavy daytime operation and high consumption → the owner-invested model is likely to come out ahead.
- Mostly night shifts, or low consumption → a roof lease can be the steadier choice.
- A customer asking you to evidence renewable electricity use → the owner-invested model tends to win, because the power you consume yourself counts as evidence.
- No capital to commit, or no wish to take on running a power plant → the roof lease fits.
What to check in the contract
- 1Waterproofing and leaks: state who is responsible for the penetrations made during installation and for any leak afterwards, and how far compensation extends.
- 2Structural reinforcement: agree who pays if the roof structure review finds that reinforcement is needed.
- 3Roof repairs: if the roof has to be replaced during the term, check who pays to remove and reinstall the system.
- 4Early termination: check what happens to the contract if the building is sold, extended, or changes use.
- 5Reinstatement: define the scope of removal and roof restoration at the end of the contract.
- 6Insurance: check who takes out fire, storm and flood, and liability cover, and what each policy covers.
How to compare them on the numbers
A fair comparison means building a 20-year cash flow for both on the same basis. For the lease, that is the rent received each year. For the owner-invested case, it is the upfront investment, the annual savings and power sales, operating costs, and the annual degradation rate. Put tax and financing costs on top of that, and the real difference shows up.
Sources
- · GRIDAEND feasibility assessment methodology (as of 2026-08)
This article is drawn from public sources available at the time of writing and is for reference only. Rules and market prices change. It cannot be used as the basis for an investment or contract decision.