Testing in Japan is scheduled to begin later this year.
Wayne Gerdes -
CleanMPG - June 9, 2012
2012 Toyota Prius PHEV – The cord will someday be bi-directional for more than just data exchange.
The promise of V2G is becoming a reality in Japan and none too soon given the earthquake prone region.
In a release from earlier this week, Toyota says it has developed a vehicle to home (V2H) system for the mutual sharing of power between battery electric-powered vehicles and homes. The V2H system is will begin testing using Prius PHEVs at the end of 2012 in approximately ten households as part of the Toyota City Low-Carbon Verification Project2 (Toyota City Project) that began in April 2010.
The newly developed V2H two-way electric power supply system can supply power from home to vehicle as well as from vehicle to home. An AC100 V (Japan base home Voltage spec) inverter onboard the Prius PHEV converts stored power into AC suitable for home use, while power flow is controlled according to communication between vehicle, charging stand and the home. With this new method, low-carbon electricity ("green" electricity) generated from regional or home solar generators, or low-cost late night electricity, can be stored in a vehicle's drive battery and then used to supply power to the household during peak consumption times. This kind of optimal energy flow can be automatically controlled by a home energy management system (HEMS).
In An Emergency
Vehicle batteries can also be used as a power source in times of emergency by manually setting the electricity flow to supply power from the vehicle's drive battery through the charging stand to a home's lights and power outlets. With a fully charged battery and full tank of gasoline, a Prius PHEV can supply power for average Japanese household electricity use (approximately 10 kWh) for four days.
Interest in smart grid technology and expectations for the effective use of electric vehicle batteries has increased due to recent anticipated electricity shortages in Japan, the beginning of full-scale renewable energy introduction and an increased need for emergency power supplies.
Households participating in the verification tests in Toyota City will use Prius PHEVs, which can use the V2H system to supply electric power to homes, as well as function as conventional gasoline-electric hybrid vehicles once onboard electricity supply depletes to a certain level.
Toyota hopes to promote the widespread use of V2H systems while closely studying—conscious of standardization trends—system, hardware, power generation and other relevant specification standards.
In addition to the V2H system, Toyota has developed devices capable of supplying electricity from PHEVs directly to home devices, for use at emergency shelters in the event of a disaster. The devices will be installed on the PHEVs used in this round of the Toyota City Project tests.
In light of the recent power supply shortages in Japan, the Toyota City Project is working to promote regional energy management that can respond to shifts in peak usage. In response to the increasing need to control peak electricity use, the Toyota City Project will test synchronized automatic control between HEMS and regional energy data management systems (EDMS) this year. Existing energy usage optimization technology using household storage batteries will be expanded to V2H systems, making green electricity use even more effective while promoting a shift away from electric power consumption during peak-demand times.
Through the development of the V2H system, Toyota aims to contribute to low-carbon and energy-efficient electricity use and to support the Toyota City Project's goal of regional energy independence.
Toyota’s base V2G (V2H as they call it) layout
The US’ V2G projects are also in their infancy and it is doubtful they will ever make much of a dent for decades to come. Given Japan’s propensity to move forward with smart ideas, you can bet most of the country will be retrofitted within two decades once the pilots (if the pilots) have proven successful.
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