Japan has all kinds of solar-powered stuff: cell phones, cars, ships, and even carports and satellites. And now Tokyo-based Sekisui House plans to sell apartments fitted with sophisticated solar energy generation and control systems, which will not only power rooms but also allow residents to sell surplus electricity directly to utilities.

The electricity will be generated via solar panels on the buildings’ roofs, with each apartment having a meter to measure how much energy has been used and sold. Sekisui House claims the sun will provide enough energy for the solar buildings as a whole, but utilities will deliver conventional power in case of emergencies.

One solar power generation system installed in a four-apartment building costs a whopping $60,000 (but there are generous subsidies provided by the Japanese government for solar equipment). Sekisui House expects to sell around 300 of these systems by the end of January 2010 and sees about 30% of all apartments that it builds equipped with them in the future.

Via Nikkei [registration required, paid subscription]