The Toyota Dream House PAPI (Japanese site) is a concept home designed by Professor Ken Sakamura of the University of Tokyo. Building on the TRON intelligent home project, the Toyota Dream House PAPI (and I have no clue as to what PAPI stands for) integrates a prototype Toyota-designed plug-in Prius as a secondary power source.
Toyota Dream House PAPI was designed to interface with other Toyota technologies. One of the most important of those other technologies is Toyota Motor Corporation's Prius hybrid sedan, which can also be used to supply electricity to the intelligent house for 36 hours in an emergency, such as an earthquake that cuts off normal electrical supplies.
Conversely, the house can supply electricity to the battery packs of the vehicles via the stand in the middle of the garage. Some of that electrical energy can be obtained from solar cell panels that cover the roof, plus the sides of the structure. The house also uses solar heating and fuel cells, which makes it a kind of hybrid energy house.
Green Car Congress has some added detail. Despite the building-integrated solar, the Toyota Dream House is not really a "green home" design. Most of the emphasis is on ubiquitous wireless networks and "smart home" controls, rather than on high-efficiency high-style construction and materials. Still, it's good to see Toyota doing more than just talking about the possibility of gas-optional hybrids with home power use; the combination of BIPV and plug-in Prius would go well with "microgrid" distributed power networks.
This is great to see, if nothing else because it's the first demonstration of Amory Lovins's proposal for Hypercars as distributed power sources. Let's hope it & the other hypercar ideas catch on.