The solar power industry boomed in Japan years ago thanks to policies that made it competitive to conventional energy sources.

For example, in 2003 Japan generated half of all solar power in the world, developed 44% of all new solar energy equipment and installed 5 times more new solar power capacity than United States.

Today, increasingly more buildings are equipped with solar cells for the purpose of generating power for the entire building. Outside (or inside) such buildings you can sometimes see a panel with meters that measure power generated by solar cells, just like this one here:


The top meter displays current power generation in kW and the bottom one shows daily amount of generated power in kWh.