Plug in your house. Toyota It may be hidden behind a fuzzy grey triangular panel in the trunk, but the 2016 Toyota Mirai fuel-cell car offers a novel and innovative feature that could let it power your home for a day or two in the event of an emergency.

Toyota executives say they haven't decided whether to offer the power-out capability on the 200 Mirais that will be sold in the U.S. next year.

A power-out jack and associated energy station, not currently offered on any passenger cars, would likely offer a unique selling proposition that underscores the Mirai's ability to generate emission-free electricity--and quite a lot of it too.

The energy capacity of the fuel-cell vehicle's 5 kilograms of hydrogen, compressed at 10,000 psi, is more than 150 kilowatt-hours.

While a portion of that energy is lost in the conversion from hydrogen to electricity, the Toyota press materials say that's enough to power a household for up to seven days.

That would like not be a typical U.S. household--using 32 kWh a day--but a typical Japanese one, at a considerably more modest 10 kWh.

The plug itself uses a CHAdeMO connector, and would connect to an energy station that converts the high-voltage direct current from the Mirai's fuel cell into the 100-volt alternating current used in Japanese buildings.

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Following the 2011 earthquake and tsunami that devastated parts of Japan, the country instituted a "demand response" energy policy under which electricity users are asked to limit energy use during peak demand periods.

Normally, residents comply by turning down air conditioning or shutting off lights.

But Toyota suggests that the Mirai's power-out capability could allow them to power their homes using the fuel cell instead during those periods.

That's the theory behind Nissan's Leaf-To-Home energy station, which lets its Leaf electric car provide up to two days of power to a Japanese home from its 24-kWh battery pack.

Hydrogen fuel-cell vehicles could similarly provide electric power during emergencies when power grids are completely offline, as battery-electric cars did in 2011.

Unlike electric cars, however, a hydrogen fuel-cell vehicle has only a one-way connection to the grid--it can't increase its onboard energy capacity by plugging in to recharge a battery pack.

While hydrogen fuel-cell cars do have battery packs to assist with temporary high power demands, the Mirai uses a nickel-metal-hydride pack very similar to those used in Toyota Prius hybrid vehicles.

Still, the ability of a hydrogen-fuel vehicles to provide electricity for hours at a time would likely prove an interesting selling point in regions of the U.S. where many households have backup generators to compensate for frequent power outages.

The 2016 Toyota Mirai hydrogen fuel-cell sedan will go on sale in Japan in December, with U.S. sales and leasing to begin in the second half of next year.

Toyota's North American arm is helping to fund the development of hydrogen fueling stations in Southern California and five Northeastern states.

The company expects to have sold 3,000 Mirai hydrogen vehicles by the end of 2017, it said this week at a media drive held before the Los Angeles Auto Show.

Toyota provided airfare, lodging, and meals to enable High Gear Media to bring you this first-person report.