Methodology & Data Sources

Radical transparency. Here we document exactly how we calculate savings, production, and ROI for solar installations in Málaga.

Last reviewed: 27 December 2025

1. Primary Data Sources

Our simulations use official APIs and documents to guarantee accuracy:

Solar Production (Irradiation):
We use the PVGIS-SARAH2 database from the European Commission.
Spatial resolution: 0.05° x 0.05°. Horizon calculated automatically.
Electricity Prices (PVPC):
Red Eléctrica de España (ESIOS). 12-month average for domestic profiles 2.0TD.
Tax Ordinances (IBI/ICIO):
We consult the official Provincial Bulletins (BOP) of Málaga directly for:
- Málaga City Council (IBI Tax Ordinance 2025)
- Marbella City Council (Tax Ordinance)
- Mijas, Fuengirola, Estepona, etc.

To avoid overestimating savings, we apply conservative margins:

System Losses	We apply 14% (PVGIS standard) to cover losses due to temperature, cabling, and inverter.
Annual Degradation	0.5% per year (standard linear warranty for Tier 1 panels).
Average Self-Consumption	In studies without battery, we estimate 40-50%. With battery, 70-80%.
Energy Inflation	We calculate 25-year scenarios with a conservative energy inflation rate of 3% annually.

Links to key regulations for self-consumption in Andalusia: