A 21 kWp example with bill, specific yield, cost and tariff: 4.4 years.
The most frequent question when deciding on a PV investment is "how many years until it pays for itself?" Although the answer may seem complex, it rests on four variables: your consumption, your region's solar resource, system cost and electricity price. Here is the step-by-step calculation.
1. Find annual consumption
Divide your monthly bill by the unit electricity price (all taxes included) to find monthly kWh consumption. Example: a 12,000 TRY bill / 4.5 TRY = 2,667 kWh a month, i.e. 32,000 kWh a year.
2. Calculate the required capacity
Divide annual consumption by your region's specific yield (annual output of 1 kWp). For Ankara the specific yield is about 1,520 kWh/kWp: 32,000 / 1,520 = 21 kWp. With 580 Wp modules this is about 37 modules and requires roof area of around 150 m².
3. Find the investment cost
In early 2026 turnkey costs for commercial rooftop PV in Türkiye range from about 28,000 to 33,000 TRY/kWp (including modules, inverter, structure, cabling, labor and permits). For 21 kWp: 21 × 30,000 = 630,000 TRY.
4. Calculate annual savings
Annual production × unit price: 32,000 kWh × 4.5 TRY = 144,000 TRY/year.
5. Simple payback
Investment / annual savings = 630,000 / 144,000 ≈ 4.4 years. Considering modules run for 25-30 years, more than 20 years of "free" electricity is produced.
Factors affecting the calculation
- Electricity price increases: If tariffs rise, payback shortens. With a 10% annual increase the period in this example falls to 3.8 years.
- Degradation: A 0.4% annual drop in TOPCon modules affects total 25-year production by about 5%.
- Self-consumption ratio: If daytime consumption is high, savings are at the full unit price; different net-metering conditions may change the outcome.
- Shading and orientation: Orientations other than south can bring 5-15% loss.
Financing and tax
Investment incentive certificates, SME-support or agricultural grant programs can reduce investment cost. If you use a loan, add the interest cost separately to the payback calculation. The PV simulator on our site does all these steps for you in seconds.
For a more exact estimate, you can request a free survey and receive a custom quote based on satellite imagery, shading analysis and your bill.