About Solar World
Solar World (world.solarleb.org) is a free, open tool that estimates how much electricity rooftop solar panels could produce on any building on Earth. Click a rooftop anywhere — or draw a custom area — and see realistic production, savings, payback and avoided CO₂.
It is one of two sibling tools that share the same solar estimation engine.
What you can do
- Click any building worldwide for a rooftop solar estimate from its footprint and location, or draw a custom area.
- See production broken down by day, week, month and year (a full 365-day simulation).
- Set panel orientation and tilt, or apply the optimal values computed for the location.
- Estimates factor in real-world cloud cover from NASA satellite climatology — not just a clear-sky maximum.
- Compare self-consumption, battery sizing, costs, savings, payback and CO₂ avoided, in your chosen currency.
- Available in six languages: English, French, German, Spanish, Portuguese and Arabic.
SolarLeb — the country portal
SolarLeb is the country-specific sibling of Solar World. It adds an aggregated map (governorate → district → city → building), live weather stations, crowd-sourced rooftop labels, a directory of approved installers, and saved solar systems — for a single country at a time (Lebanon today; more to come).
Open SolarLebHow the estimate works
Both tools run a full 365-day simulation for the selected rooftop. Production is attenuated by month-by-month cloud cover derived from NASA satellite climatology, with an uncertainty band reflecting year-to-year cloud variability — so the numbers reflect a realistic year, not an idealised clear sky. The engine also computes the optimal panel tilt and orientation for the location, which you can override with your own values.
Estimates are planning indications, not a guarantee: actual output depends on panel efficiency, shading from nearby trees or buildings, installation quality, and local weather in any given year.
Data and technology
Building footprints come from OpenStreetMap; solar irradiance and cloud data from NASA POWER; grid CO₂ intensity and electricity prices from Our World in Data (Ember). Maps render with MapLibre GL over CARTO basemaps and Esri satellite imagery, and the backend is built on GreyCat.