Jasna Tomic, CALSTART - California Public Utilities Commission


Jasna Tomic, CALSTART - California Public Utilities Commission

Vehicle-to-Grid Opportunities

Clean Transportation

Technologies and Solutions

Jasna Tomic

Plug-in Electric Vehicle Integration Issues

California Public Utilities Commission

San Francisco, CA

July 15, 2009

Copyright CALSTART 2009

Power Grid Changing

•“Smart Grid”

• Integrating Distributed Generation

• Increasing generation from renewables


Copyright CALSTART 2009

Vehicle to Grid- Integration of

Transportation and Power Grid

Arrows indicate direction of power flow

(Kempton &Tomic, JPS, 2005) 2

Copyright CALSTART 2009

Battery Size and Daily

Driving of EVs and PHEVs

Battery size in EVs

15- 50 kWh

PHEVs 10 – 15 kWh

Daily driving is ~ 30

miles per day

Lots of unused energy




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Uses for V2G Power

Base-load Power

Peak Power

Ancillary Services

Energy Storage



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Electricity Market Prices

• Ancillary Services Capacity Price

– Frequency Regulation $15-55/MW-h

- Spinning Reserves $20/MW-h

Capacity price ($/MW-h) +

Energy price ($/MWh)

Energy Price

• Baseload Power 2-10 c/kWh

• Peak Power 5-80 c/kWh


Copyright CALSTART 2009

V2G Provides New Source of

Distributed Generation

•50% of cars as EDVs increase electric load ?

100 Million cars

x 15,000 Miles per year / 4.8 Miles per kWh

= 312 Billion kWh per year at off-peak times

= 7 % of 2020 total national load

•With V2G, these EDVs also provide a huge power


100 M cars x 15 kW x 0.5 avail. = 750 GW of DG

> 70% of 2020 national electric power


Conclusion: Even 50% of cars as EDV, IF they have

V2G, probably REDUCE grid infrastructure requirements


Copyright CALSTART 2009

Vehicles & Electric Grid

• Two large sector that can be


• Smart interaction between vehicle

fleet, grid and intermittent renewable

• Large, low-cost storage for


• Vehicle-to-Grid (V2G) power as

bridging technology


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Benefits of V2G

• Cost of EVs & PHEVs is relatively high

• V2G provides revenue to owner and helps

offset that higher cost

• Dual use for clean transportation and grid

power support - shared capital cost

• Encourages early adoption of EVs & PHEVs

• Distributed generation

• Energy storage for grid and integration of

renewable sources


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• V2G can be integrated and implemented in

limited deployment now

• TOU rates would support controlled


• Allowing discharging of EVs and other

distributed generation back to the grid

provides greater benefit to the grid

– Use of stored electricity, grid stability, new

generation capacity

• With installation of ‘smart grid’ deploy in

parallel new applications and technologies

such as V2G that really put the smart grid

to use


Jasna Tomic



Clean Transportation

Technologies and Solutions SM


Copyright CALSTART 2009

Ancillary Services


• Ancillary services ensure electric power grid is

stable and reliable

• Regulation: On-line generation synchronized to

the grid to respond to demand variations (voltage

and frequency). Energy is increased/decreased

instantly (~2-3 min) via automatic generation

control (AGC)

• Spinning Reserves: Generating capacity

synchronized and ready to respond for ~10 min in

case of power failures.

• Require units operating but not producing energy

• Payments consist of:

Capacity price ($/MW-h) + Energy price ($/MWh)

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