Germany leads in balcony solar installation- 1 million installed in 2023-2025 ($200 to $1200 solar modules installed on baconies. The boom is the largest in Europe for solar balcony installations. Japan is sending a delegation to learn from Germany. Renewables overtook coal for first time worldwide. In Germany the cost of this electricity from soalr balcony installs is half that of electricity from the grid. Berlin University Applied Sciences says it pays for itself in 4-7 years, after that the electricity has no cost. Solar modules life is 30 years, batteries life is 7-10 years. With 4 modules about half the needs for electricity for a household can be met.