Solar Operating Models Compared: Ownership, Leasing, Contracting

The question is rarely whether photovoltaics goes on the roof, but who owns it. Three operating models cover the spectrum: purchase, leasing, and Contracting (third-party ownership / PPA-style model) combined with a roof lease. They differ in capital commitment, balance sheet impact, returns and responsibility, and the right choice depends on the property, not on the provider's preference.

The three models at a glance

At NEXA, the three routes are called NEXA Own, NEXA Lease and NEXA Zero; the mechanics behind them are standard across the industry and transferable.

Model 1: Ownership. Maximum return, maximum commitment

Whoever buys keeps the full value creation: avoided electricity costs, feed-in revenue, depreciation. The full calculation is in the article Is photovoltaics worth it for commercial roofs in 2026? The tax leverage is substantial: the investment deduction allowance (IAB) deducts up to 50% of the investment from profit in advance, and KfW 270 financing stretches the liquidity burden over up to 30 years.

Ownership fits when: equity or credit capacity is available, the self-consumption share is high, and the company plans to stay at the site long term.

Model 2: Leasing. A predictable installment instead of an investment

With PV leasing, a leasing company finances the system, the company pays a fixed monthly installment and typically takes over the system after around 10 years. The installment is an operating expense; whether the structure keeps the balance sheet light depends on the accounting standard (structuring is possible under German GAAP (HGB), while IFRS 16 requires capitalizing a right of use).

Leasing fits when: liquidity needs to be preserved, but the company wants ownership and the self-consumption advantage at the end of the term.

Model 3: Contracting with a roof lease. Zero investment, zero responsibility

Under Contracting, the system remains the property of the operator. The building owner leases out the roof area (roof lease), receives an ongoing payment and typically purchases the solar power below grid prices via a PPA. On the balance sheet, the project stays entirely off the books; maintenance, insurance and monitoring are carried by the operator.

Contracting fits when: no capital should be tied up, no balance sheet impact is wanted, or energy infrastructure simply is not part of the core business. Details on the lease mechanics are on the NEXA Zero page.

The decision logic: three questions

1. Is capital available and well deployed? If the internal rate of return of other projects is below the PV return: buy. If not: leasing or Contracting.
2. What balance sheet impact is acceptable? Off-balance only works with Contracting. Leasing sits in between, purchase capitalizes in full.
3. Who should be responsible for operations? Ownership can be delegated via an O&M contract, Contracting removes the responsibility entirely.

The honest answer is property-specific: the same company is best off buying at its production site and leasing out the roof of its distribution warehouse. That is why the initial analysis in NEXA ONE calculates all three models in parallel, using the same official input data (LoD2, PVGIS): Start your analysis