plug-in vehicles and the electric grid

Plug-in Vehicles and the Electric Grid

Mark Kapner, PESenior Strategy Planner

Austin EnergyMark.kapner@austinenergy.com

1. How Many PHEVs Can the Power

System Accommodate without

Additional Generating Capacity ?

2. How does the Replacement of

Conventional IC Engine Vehicles

by PHEVs Affect Greenhouse Gas

Emissions ?

3. How will Large-scale Deployment

of PHEVs Effect the Grid ?

Questions

Methodology to Answer

Question 1Estimate existing idle generation capacity in a NERC region using a “valley filling” methodology

System load profile data from NERC and EIA

Simplified hourly load profiles to two 24 hour dispatches,a typical summer and typical winter day

Simulate the economic dispatch of generators

Generation available to charge PHEVs = available capacity minus generation dispatched to meet load.

Assumed that peaking plants are not used to charge PHEVs

Coal and Natural gas-fired units de-rated to account for planned outages

Austin Energy Generation

400

600

300

700

380

1

Natural Gas CombustionTurbine

Natural Gas Steam

Combined cycle

Coal

Nuclear

Summer Day Typical Load Profile

0

500

1000

1500

2000

2500

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

hour ending

MW

Nuclear

Coal

Comb Cycle

Other Gas-fired

Peakers

Typical Winter Day

0

200

400

600

800

1000

1200

1400

1600

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Hour Ending

MW

Nuclear

Coal

Comb Cycle

NERC Map

Specific Energy and Energy Storage Requirements by Vehicle Class

Vehicle Class Specific Energy in kWh per mile

Battery Capacity

Compact 0.26 8.6

Mid-Size Sedan 0.30 9.9

Mid-size SUV 0.38 12.5

Full-size SUV 0.46 15.2

Conclusion

(assuming max 2 kW charging rate)

NERC Region Technical Potential in Million PHEVs

ECAR 28.6

ERCOT 15.5

MACC 10.4

MAIN 13.1

MAPP 6.1

NPCC 15.6

FRCC 6.5

SERC 32.5

SPP 15.1

NWP 2.8

AZ & RMP 5.8

CNV 6.0

Total USA 158 million PHEVs

GreenHouse Gas Emissions

0

50

100

150

200

250

300

350

400

450

500

Conventional Hybrid PHEV - coal PHEV - gas combcycle

Gra

ms

of

CO

2 p

er m

ile

Nitrogen Oxides - grams per km

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

EV - coal

EV -nat gas

gasoline avg

gasoline - new

Findings Valley Filling can charge approximately 75% of all

light duty vehicles in the US, if they were PHEVs

Potential Gasoline Displacement by PHEVs = 6.5

Million Bbls per Day (71% of total gasoline

consumption)

Assuming utilities have some control over when

charging occurs, PHEVs could increase minimum

system load, increase the utilization of baseload units,

and decrease plant cycling, and increase utility profits

(and/or reduce electric rates).

Findings PHEVs charging on today’s coal-fired generation have about

33% lower GreenHouse Gas emissions per mile than conventional

vehicles, charging on gas-fired combined cycle, have about 78%

lower GHG emissions.

Deployment of PHEVs facilitates the introduction of more wind

energy in regions where wind generation is strong at night.

Distribution engineers have expressed concern that distribution

transformers may not be designed to sustain a constant high

loading without a daily “cool down” period.

Studies

Pacific NW National Laboratory: Impacts Assessment of Plug-

In Vehicles on Electric Utilities and Regional US Power Grids

EPRI and NRDC: Environmental Assessment of Plug-In Hybrid

Vehicles

NREL: An Evaluation of Utility System Impacts and Benefits of

Optimally Dispatched Plug-In Hybrid Electric Vehicles