Is Rooftop Solar Worth It for Commercial Buildings in 2026? The Math with Real Numbers

Short answer: in most cases yes, provided the load profile matches the roof. The calculation has three levers: what the system costs, what your grid power costs, and how much of the solar power you consume yourself. All three can be quantified precisely in 2026.

The cost side: €700 to €1,200 per kWp

Commercial rooftop systems in 2026 cost, depending on size:

The price per kWp falls as size increases: scaffolding, grid connection and planning are spread across more capacity. Roof condition and grid connection can shift the price, which is why every serious calculation starts with a roof check based on official data.

The revenue side: self-consumption beats everything

Commercial electricity typically costs 25-30 ct/kWh all-in in 2026, net of VAT: energy and standing charges including grid fees, levies and electricity tax. The figure depends heavily on the consumption band and on when the contract was signed. New contracts for large offtakers sit well below it, and the BDEW price analysis of April 2026 puts small and medium industrial customers at 16.7 ct/kWh. What matters for your own calculation is your own purchase price from your last invoice, because that is exactly what self-consumption replaces. Every kilowatt-hour from your own roof that you consume yourself replaces that price. Surplus power is remunerated under the EEG at 5.44 ct/kWh (systems of 40-100 kWp, partial feed-in, commissioned from 1 August 2026; all rates in the overview of the Einspeisevergütung (feed-in tariff) for 2026).

The ratio is decisive: self-consumption is worth four to five times as much as feeding in. A logistics operation with daytime load (cooling, conveyors, charging infrastructure) consumes 60-80% of its solar power itself. A warehouse without daytime load reaches 20-30%; there, feed-in carries more weight and the return drops.

Worked example: 100 kWp on a company roof

Result: around €16,000 net return per year, payback after 5 to 7 years, followed by 13 or more years of returns given the 20-year EEG remuneration period and a module lifetime of 25 years or more. With the Investitionsabzugsbetrag (IAB, investment deduction under § 7g EStG), the tax relief on up to 50% of the investment can additionally be brought forward.

What tips the calculation

Three points decide a project more often than the module price does:

1. Roof condition. If a refurbishment is due within the next 10 years, it belongs before the PV system. Dismantling and reinstalling the array costs a mid five-figure sum.
2. Grid connection. The available connection capacity limits system size. The grid connection request belongs at the start of the project, not at the end.
3. Load profile. Weekend operation, shift patterns, seasonal load: the profile determines the self-consumption share and with it the return.

No equity? Then the question changes, not the answer

Rooftop solar pays off in 2026 even without investing your own capital; the value creation simply shifts:

• NEXA Own: buy and own, full value creation and full depreciation in the business, financeable via KfW 270.
• NEXA Lease: a predictable monthly rate instead of an investment, ownership at the end of the term.
• NEXA Zero: lease out your roof, €0 equity, Dachpacht (roof lease) payments from commissioning.

Which model delivers the best figure for your property is calculated in parallel by the initial analysis in NEXA ONE, based on official data (LoD2 building model, PVGIS irradiance). Free of charge, start the analysis.