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Toyota vehicle-to-home technology turns Prius Plug-in into an emergency generator


June 6, 2012

Toyota will begin testing its V2H technology later this year at approximately 10 of its Toyota City smart homes

Toyota will begin testing its V2H technology later this year at approximately 10 of its Toyota City smart homes

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Electric vehicle charging has been a hot topic for years, but it's mostly been a one-way discussion: how the EV charges from a given home charging system. Toyota turns the conversation around, experimenting with how the home can draw power from the EV. Toyota's vehicle-to-home (V2H) charging system offers two-way charging between the Prius Plug-in and a home power supply.

Obviously, the Prius Plug-in's small lithium-ion battery isn't enough to pull a home off the greater electric grid, but Toyota envisions the two-way system working as an emergency generator during blackouts. It also envisions the Prius Plug-in drawing power during off-peak hours and then feeding that stored power back to the home during peak times, helping to lower energy costs. Toyota says that the Prius Plug-in can power an average Japanese home for up to four days.

The V2H system equips the Prius Plug-in with an AC100 V inverter that converts the car battery's direct current into the alternating current used in homes. Communication between the car, the charger and the Home Energy Management System (HEMS) facilitates power flow between the car battery and home.

The V2H charging tech is part of the Toyota City Project, an ongoing research project on smart grid technology supported by Japan's Ministry of Economy, Trade and Industry. Toyota City is one of several regions selected to participate in METI's Next-Generation Energy and Social System Demonstration project. A series of model homes are serving as the test bed for the project. The homes use a combination of smart appliances, solar panels, household power storage, home energy management and two-way vehicle charging to stabilize power demands and optimize energy usage. The project also aims to optimize energy usage at the community level. According to Toyota, 40 households are currently participating.

The Toyota City Project began in 2010, with Toyota completing construction of the homes last summer. In one of the next phases of the project, Toyota will begin testing the V2H charging system in about 10 of the model homes.

Toyota isn't the only automaker working on a system that allows for car-to-home energy flow. Nissan has previously floated the concept and last week announced the "Leaf to Home" system . Like Toyota's system, the Leaf to Home uses special charging equipment to enable the Leaf to send electricity from its 24 kWh battery back into the home. Nissan says that the Leaf can power an average Japanese home for two days. It plans to bring the system to Japanese showroom this month.

Source: Toyota Global

About the Author
C.C. Weiss Upon graduating college with a poli sci degree, Chris toiled in the political world for several years. Realizing he was better off making cynical comments from afar than actually getting involved in all that mess, he turned away from matters of government and news to cover the things that really matter: outdoor recreation, cool cars, technology, wild gadgets and all forms of other toys. He's happily following the wisdom of his father who told him that if you find something you love to do, it won't really be work. All articles by C.C. Weiss

Been done many times starting with ACPropulsion in the late 90's Ford E-Ranger. Not only ran the home but put out 150kw into the grid if needed. Many other vehicles now have 120-240vAC outputs as standard or option. Kind of makes what Toyota did seem small.

During the Fla Hurricanes I used my EV's to power my home for 3 days before the power came back on and all it took was a $100 12vd inverter and unlike my neighbors, didn't need a gas generator.


Have to agree with jerryd, not much of an announcement. For what was once innovative, insisting on sticking with a parallel hybrid tech and very small batteries is on the verge of making Toyota a has been in the hybrid/electric market.

Max Kennedy

I like the idea of using the car for emergency power. Many home owners possess a 12v inverter and use it during brownouts(akin to a UPS.) Add solar charger/PS and we will never experience brown outs. All country homes should have an inverter.

automotive concerns

Somehow I don't think that the money you save by buying electricity off peak to use during on peak is not going to pay for the early death of the battery.


A step in the right direction just go to make it cost efficient to give the power companies a bit of competion from petrol and LPG.


Any idea when it'll be available in the US?


A good way to fight black-outs in Dominican Republic or anywhere else. You need a hybrid vehicle some other resources and a desire not to be beaten by the mosquitos in a hot night in the middle of a blackout.

Ramon Acosta
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