How much power does a balcony solar panel produce?

South-facing and tilted: roughly 750 kWh/year in northern Europe, 900 in central Europe, 1,100+ in the sunny south. Mounted vertically on a railing, subtract about 30%. At €0.25/kWh with 70% self-consumed, that’s €130-200 of yearly savings — enough to pay back a €500 kit in around 3-4 years in most of Europe.

In most EU countries, plug-in kits up to 800 W of inverter output are allowed with a simple notification to the grid operator or none at all; Germany, Austria, and increasingly Italy and France have explicit simplified rules. Two separate questions to check: your building’s rules on facade appearance (condominium approval for railing mounts) and whether your meter is bidirectional. Renters can usually install and take the kit when they move.

Poorly. North-facing panels in Europe produce 40-50% of the south-facing figure, and even partial shade (a railing bar, a neighbouring building for 2 hours a day) cuts disproportionately because it degrades the whole panel’s output. East or west orientations are fine — 80% of south — and east has the perk of covering the morning consumption peak. If your only option is north or heavy shade, the payback stretches beyond 10 years and the money is better spent elsewhere.

Yes — a new generation of balcony batteries (1-2 kWh) sits between panels and inverter, stores midday surplus and releases it in the evening, pushing self-consumption from ~70% toward 90%+. They add €500-900 to the system, so run the numbers: they make sense with higher electricity prices and if nobody is home at midday. A power station with solar input is a flexible alternative that doubles as blackout backup.