Toyota Motor Corporation (TMC) announced yesterday that it has developed a
vehicle to home (V2H) system for the mutual sharing of power between
electric-powered vehicles, such as plug-in hybrid vehicles (PHVs) and electric
vehicles (EVs), and homes.
The V2H system will start testing, using Prius PHVs, at the end of 2012 in
approximately 10 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 inverter
onboard the Prius PHV 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 (or "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).
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.
According to Toyota, with a fully charged battery and full tank of gasoline, a
Prius PHV can supply power for an average Japanese household (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 PHVs, 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. TMC developed its V2H system
while closely complying with existing charging and communications specifications
defined by the International Organization for Standardization (ISO) and
International Electrotechnical Commission (IEC), as well as with electrical
safety standards and regulations.
Going forward, TMC 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.
