v2grid

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Abstract of Vehicle-to-Grid V2G

Electric drive vehicles can be thought of as mobile, self-contained, and-in theaggregate-highly reliable power resources. "Electric-drive vehicles" (EDVs) include

three types: battery electric vehicles, the increasingly popular hybrids, and fuel-cellvehicles running on gasoline, natural gas, or hydrogen. All these vehicles have withinthem power electronics which generate clean, 60 Hz AC power, at power levels from10kW (for the Honda Insight) to 100kW (for GM's EV1). When vehicle power is fedinto the electric grid, we refer to it as "Vehicle-to-Grid" power, or V2G.

With the popularization of electric vehicles and the construction of charging stations,the understanding of people to the electric vehicle and the changing station is not onlyconfined to the transportation and the "gas station". It is desired to exploit moreextensive application. The concept of V2G was firstly brought out by Willet Kempton

of the Delaware University. The initial goal of V2G was to provide peak power, thatis, the electric vehicle owners charging the vehicles in low load with lower price anddischarging the vehicles in peak load with higher price. Then, the vehicle owners canget the profits from the V2G project. The functions of the vehicle in power grid wereexpanded, and the conclusion was get that benefit of providing peak power issignificantly less than providing auxiliary services to the power grid . The V2Gresearch also was carried out in some other countries such as Denmark, Britain andGermany, etc .

Introduction of Vehicle-to-Grid V2G

The first V2G requirement is the power connection. Battery vehicles must already beconnected to the grid inorder to recharge their batteries; to add V2G capabilityrequires little or no modification to the charging station and no modification to thecables or connectors, but on board power electronics must be designed for this

purpose had "zero incremental cost."

The second requirement for V2G is control, for the utility or system operator torequest vehicle power exactly when needed. This is essential because vehicle powerhas value greater than the cost to produce it only if the buyer (the system operator) can

determine the precise timing of dispatch. The automobile industry is moving towardsmaking real-time communications a standard part of vehicles. This field, called"telematics" has already begun with luxury vehicles; over a period of time it will beavailable for most new car models. Whether using built-in vehicle telematics, or in theinterim using add-on communications, the vehicle could receive a radio signal fromthe grid operator indicating when power is needed.

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The third element of precision, certified, tamper-resistant metering, measures exactlyhow much power or ancillary services a vehicle did provide, and at which times. Thetelematics could again be used to transmit meter readings back to the buyer for creditto the vehicle owner's account

Thinking about the metering of V2G expands the usual concept of a "utility meter."Electronic metering and telemetric appear to have efficiency advantages ineliminating the meter reader, transfer of billing data to the central computer, and themonthly meter-read cycle. More unnerving, electronic metering and telemetric alsoeliminates the service address! An onboard meter would transmit its own serialnumber or account number with its readings, via telemetric, and presumably thiswould be billed in conjunction with a traditional metered account with a serviceaddress. A large-scale V2G system would automate accounting and reconciliation of

potentially millions of small transactions, similar to the recording and billing of callsfrom millions of cellular phone customers.Thus the mobile metered KWhs or ancillaryservices wold be added or subtracted to the amount registered on the fixed meter toreconcile both billing amounts.

Concept Of V2G :

Figure schematically illustrates connections between vehicles and the electric powergrid. Electricity flows one-way from generators through the grid to electricity users.Electricity flows back to the grid from EDVs, or with battery EDVs, the flow is twoways (shown in Fig. as lines with two arrow ). The control signal from the gridoperator (labelled ISO, for Independent System Operator) could be a broadcast radio

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signal, or through a cell phone network, direct Internet connection, or power linecarrier. In any case, the grid operator sends requests for power to a large number ofvehicles.

The signal may go directly to each individual vehicle, schematically in the upper rightof Fig. , or to the office of a fleet operator, which in turn controls vehicles in a single

parking lot, schematically shown in the lower right of Fig. , or through a third-partyaggregator of dispersed individual vehicles' power (not shown). (The grid operatoralso dispatches power from traditional central-station generators using a voicetelephone call or a T1 line, not shown in Fig .)

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