🇪🇸 Solar Calculator Spain
Enter your city, monthly electricity bill, and roof area — get system size, panel count, autoconsumo savings, and payback period in euros.
How to Use This Calculator
Select your city and enter your electricity bill
Choose the city or region closest to your location. Spain's solar resource varies enormously — Seville and the Canary Islands average over 5.5 peak sun hours per day while Bilbao in the Basque Country averages only 3.8. This dramatically affects how many panels you need and your payback period. Enter your monthly electricity bill from your Spanish utility (Endesa, Iberdrola, Naturgy, or one of the alternative suppliers). Check the factura de electricidad for the total monthly amount.
Set roof area and system size
Enter the south-facing roof area available in square metres. Each 550W panel takes approximately 2m² including spacing; a 5kWp system needs roughly 20m². System size (kWp) can be adjusted to match your roof space and budget — the calculator will warn if the system won't fit. Most Spanish homes install between 3-8 kWp. Larger systems require authorization from your autonomous community for systems above 100 kWp.
Choose autoconsumo and battery options
Autoconsumo (Royal Decree 244/2019) is Spain's self-consumption framework. Enabling it means you register with your utility to sell excess solar to the grid at the market price (typically €0.05-0.10/kWh in 2026). Without registration, excess energy is still exported but not compensated. Battery storage increases self-consumption from ~55% to ~75% — especially valuable if you work away from home during solar peak hours (10am-4pm).
The Formula
The key Spanish-specific factors: the 10% IVA rate applies to solar installations rather than the standard 21% (confirmed under Spanish tax law for supply and installation as a single service). The excess compensation rate fluctuates with the Spanish electricity market (OMIE pool) — the calculator uses €0.07/kWh as a 2026 average; actual rates range from €0.05 to €0.10/kWh depending on market conditions and the compensation mechanism in your contract.
Example
Ana — Home in Seville with 8kWp system
Ana has a detached villa in Seville with a large south-facing roof. She pays €220/month to Endesa and wants to install 8kWp. She opts for autoconsumo registration and battery storage to maximize savings.
Result
Seville's excellent sunshine gives Ana a fast 7-year payback. Her 8kWp system produces nearly as much energy as she consumes annually. With battery storage, she covers 75% of her usage directly from solar — the remaining 25% comes from the grid on cloudy days and winter evenings. Over 25 years, she saves over €43,000.
FAQ
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<iframe src="https://solarsizecalculator.com/es/solar-calculator-spain"
width="100%" height="680" frameborder="0"
title="Solar Calculator Spain"></iframe>