Fuel Consumption, Operational Attributes and Potential Markets for Plug-in Hybrid Technologies

Presented at the

Climate Policy Initiative MeetingCenter for Clean Air Policy

Oct. 5, 2006 Washington DC

Danilo J. SantiniSection Leader, Technology AnalysisCenter for Transportation Research

Sponsor: Office of Freedom Car and Vehicle Technologies

U.S. Department of EnergyE. Wall, Program Manager, Office of Freedom Car and

Vehicle Technologies T. Duong, Team Leader, Vehicle Systems Technologies

2

Many Questions and Technology Options Were Not Previously Examined

Items not addressed in 2001 studies by EPRI and Argonne– Li-ion batteries– Varying electric operations capabilities – top speed, acceleration rate– Effects of highly variable, often wide SOC swings on battery power/life– Multiple HEV powertrain configurations– In-use vs. certification cycle fuel economy – Charge depletion w/o EV only operation (“blended mode”)– Incremental cost/benefit evaluations– Towing requirement effects– Isolation of HEV vs. PHEV incremental benefit/cost– Urban vs. non-urban & morning vs. other emissions– Detailed comparison of trip characteristics to potential PHEV capabilities

3

Oil Savings: Each PHEV (Full HEV) Sharply Reduces Oil UseEven If No Electricity is Used, Far More if Electricity is Used

4

Estimate of Daily VMT Pattern From NHTS 2001: 11.5% of National VMT by Those Traveling <=20 Miles; 48.2% for <=60 Miles

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300Daily Travel (Miles/Vehicle)

% o

f Sam

pled

Veh

icle

VM

T

Distribution of VMT by Vehicles in the 2001

NHTS Travel Day File

Question: Is Potential for Replacing Gasoline VMT With Electric VMT ~ 12% if a PHEV20, ~ 50% if a PHEV60?

5

Reality: Potential is Greater. Regardless of Daily Miles, PHEVs Can Travel Initial Miles Via Grid Electricity

Key assumptions: one charge per day (night?); 100% market penetration of the specified PHEV technology; all electric drive until battery depletion (not blended charge depletion). Blended

charge depletion requires more miles to use a given amount of grid kWh

74.9%(26.7%)40.6%(29.1%)23.2%(19.9%)100.0%Sum26.7%8.9%4.5%51.8%Over 60 Miles36.8%20.2%10.1%36.8%20.01-60 Miles8.1%8.1%5.3%8.1%10.01-20 Miles3.3%3.3%3.3%3.3%Up to 10 Miles

Max % VMT by Electricity

Max % VMT by Electricity

Max % VMT by Electricity

PHEV 60PHEV 20PHEV 10VMT Share in NHTS

2001

Daily Travel Range of Vehicle

PHEV TYPE

Note: the value in ( ) in the sum row is savings by those that usually exceed all electric range capability.

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Distance

SO

C (%

) 90

30

Charge Depleting (CD) Charge Sustaining (CS)

Distance

SO

C (%

) 90

30

Charge Depleting (CD) Charge Sustaining (CS)

Designing PHEVs for ZEV Range – EPRI 1.0 2001 and Argonne EVS-22 2006

7

0

5000

10000

15000

20000

25000

30000

0 10 20 30 40 50 60 70End of Life EV Range (miles)

Beg

inni

ng o

f Life

Use

able

Bat

tery

Ene

rgy

(w-h

)

Low CaseHigh Case

Note: This is usable w-h at 90% to 30% SOC. Rated kWh would be 67% higher.

Source: Sharer et al: Vehicle Simulation Results for Plug-in HEV Battery Requirements, EVS-22, Oct. 23-28, 2006

Battery energy capacity requirements as a function of ZEV range

Amount of Battery Energy Needed is Estimated to Go Up Linearly With ZEV Range

Note: energy requirement determined by needs of UDDS

8

As Range of PHEVs Rises, the Needed Battery Power to Energy Ratio Declines.

(This reduced $/kWh costs in EPRI study)

Source: Sharer et al: Vehicle Simulation Results for Plug-in HEV Battery Requirements, EVS-22, Oct. 23-28, 2006

(Power @ 10 sec 0.20 SOC) to (Beginning of Life Total Energy) Ratio

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7.5 10 20 30 40 50 60All Electric Range

W/W

h Power/Energy α 1/Range

Note: power requirement determined by needs of UDDS

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With a Less Aggressive Target All Electric Range Capability and Lighter Battery Packs, Argonne Estimates A Lower Needed Ratio of Power to Energy than did EPRI in ‘01

Sources: Sharer et al: Vehicle Simulation Results for Plug-in HEV Battery Requirements, EVS-22, Oct. 23-28, 2006Graham et al; Comparing the Benefits and Impacts of Hybrid Electric Vehicle Options, EPRI 1000349, 2001

Mid-size HEV Type

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Note: For PHEVs, no costs were estimated for glider redesign to accommodate pack.

EPRI Estimates for NiMH Batteries Have Costs/kWh Dropping for More ZEV Range; Low Incremental $/kWh Costs

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Those With Short Commutes in the EPRI 2001 Survey Had Most Interest in a PHEV20

-15%

-10%

-5%

0%

5%

10%

Low Base HighCost of Vehicle

Del

ta o

f Sha

re, P

HEV

20 -

HEV

0 .

0 to 5 mi commute

5 to 15 mi commute

> 15 mi commute

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As Powertrain (Battery!) Costs Drop, EPRI Predicted Share of All Urban HEVs Rises; For Long Commutes,

Low Cost Leads to Purchase of More ZEV Range

0%

10%

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60%

Low Base HighCost of Vehicle

> 15 mile commute case

Shar

e of

Mar

ket HEV0

HEV20HEV60

13

Percent of National Potential Created Per Estimated kWh of Battery PackMaximum National “Technical” Potential From the “Sum” Row on Slide 5.

Note: This is illustrative, not definitive. Li-ion pack costs are assumed to be same per kWh as in EPRI 1.0. kWh of packs from recent Argonne simulations. Potential shares from Table presented earlier. The primary point is diminishing marginal returns to adding battery to PHEVs, at least from 20 to 60 mi. ZEV range

Thinking the Problem Through; Illustration 1: Measures of Effectiveness per Unit of Battery Used

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Illustration 2: Considering EPRI HEV Type Market Share (not potential) Estimates, Which PHEV Will Save Most Oil?

34% PHEV20; 66% CV

17% PHEV60; 83% CV

0% HEV; 100% CV

35% HEV 65% CV

Mid-size car – HEV powertrain paired against the conventional (no other HEV competitor)

Or is the low pointelsewhere?

Is this the type of PHEV that results

in a minimum?

Source of market share estimates: EPRI 1000349, 2001 (base case vehicle costs)

Note: If the battery must be replaced in the PHEV20 and not the PHEV60, the PHEV60 is best

Does not use the same market share estimates as for slide 13. Here cost of the vehicle – marketability – has an effect on percent of the market that can be served

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Sacramento Municipal Utility District Summer Field Test Results (AC on): CS Energy Prius PHEV vs. Prius

Note: This PHEV may retain the engine start and warm-up feature of the Prius

First Field Tests of a Prius-Based PHEV on Blended Mode (ZEV Capability Limited) Imply Considerable Oil Reduction

Data source: D. MacCurdy; PHEV Prius Test Program by Sacramento Municipal Utility District, presentation CARB ZEV Symposium, Sept. 25-27, 2006

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Initial Charging InfrastructurePlug-in hybrids require relatively low power chargingWide availability of infrastructure

– Initial focus on private chargersArray of options

– 120 VAC, 15 amp (~1.4 kW)– 120 VAC, 20 amp (~2.0 kW)– 208/240 VAC, 30 amp

(~6 kW)120 VAC stronglypreferred due to cost,availability

6.3 – 8.2 hrs120 VAC / 15 A9.3 kWhFull-size SUV

5.4 – 7.1 hrs120 VAC / 15 A7.7 kWhMid-size SUV

4.4 – 5.9 hrs120 VAC / 15 A5.9 kWhMid-size Sedan

3.9 – 5.4 hrs120 VAC / 15 A5.1 kWhCompact Sedan

Charging Time 20% SOCCharger CircuitPack SizePHEV 20 Vehicle

1.2 – 1.4 kW power, 1 or 2 hours conditioning

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Available Parking Facilities and Actual Parking (of the most used vehicle)

for People in Detached Residences (59% of all U.S. households live in detached residences)

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AttachedGarage

DetachedGarage

Carport No Garage orCarport

Driveway Street Other

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Available Parking Actual Parking

More than 30% of Present Households Park their Vehicles in a Garage or Carport

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Even With No Infrastructure Investment (on Board Vehicle Charger), PHEV20s in Garages and Carports Charge Overnight

012345678

Hours to Charge

CompactCar

Mid-SizeCar

Mid-SizeSUV

Full-SizeSUV

EPRI Estimate of Infrastructure Cost vs. Hours to Charge

$0$200$1,000

Note: These estimates will be

reexamined.

PG&E Off Peak Period

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Source: S. Thesen, Electrical Service Options for Residential Customer EV and PHEV Users, 9/26/06, CARB ZEV Symposium

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A CA Utilities Survey Shows $/kWh of Off- and On-Peak Rates

Source: S. Thesen, Electrical Service Options for Residential Customer EV and PHEV Users, 9/26/06, CARB ZEV SymposiumNote: A national study of rate structures is desirable. CA may be atypical.

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$0.000

$0.025

$0.050

$0.075

$0.100

$0.125

$0.150

$3.25 $2.25 $1.25 $3.25 $2.25 $1.25 17 14 11 8 5 2

Dol

lars

per

Mile

U.S. Average Electric Rates Imply Considerable Per Mile Savings for PHEV20 Electricity Use at Present Gasoline Prices

On-peak price range

Off-peak price range

U.S. average price, 2005

On-Road Fuel Costs Per Mile - Mid-Size Vehicles on Gasoline or Electricity, City Driving

CV = 23 mpg, HEV = 40 mpg, PHEV ZEV = 0.32 kWh/mi

Dollars per gallon Residential Cents per kWh

Conventional Powertrain

Camry HEV Powertrain

PHEV Powertrain in

ZEV mode

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On Average, Hours per Vehicle Per Day are Relatively Constant Across Population Densities

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Vehicle Speed (1) Increases As Population Density Decreases (2) Is Higher Nationally For Detached Units

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Estimate of fuel saved by EnergyCS Prius vs. Prius, Standardized on Miles vs. Hours of Driving, by Driving Pattern

For the CSEnergy Type of PHEV to Save Most Gasoline vs. a Prius, It Should be Used Where Average Driving Speeds are Higher – Suburbia, Uncongested Cities, and Rural America!

Data source: D. MacCurdy; PHEV Prius Test Program by Sacramento Municipal Utility District, presentation CARB ZEV Symposium, Sept. 25-27, 2006

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SummaryBoth charge-sustaining (current) HEVs and charge-depleting (plug-in) HEVsreduce petroleum. Plug-in HEVs could cut oil use even more than full HEVs.Substantial travel, in terms of miles driven, can be transferred to electricity through plug-in HEVsAs plug-in HEV’s ZEV range increases, power to energy ratio for the battery pack declines, and battery costs should not rise linearly with additional kWh. Incremental battery cost per kWh should be carefully investigated.Charging PHEVs initially at low voltage on available residential circuits can keep initial charger and grid modification costs low. Perhaps only summer peak charging of PHEVs in most U.S. utilities would increase PHEV energy cost per mile compared to HEV mode. Thus, if a fleet of PHEVs enters the market, even low gasoline prices would not make PHEVoperation on gasoline cheaper than on off peak electricity. Therefore, promised GHG and oil use benefits over and above the HEV would likely be secure.For an initial PHEV Prius, it has been estimated that the best market for oil use reduction is suburbia, uncongested cities, and rural areas. The technology is very complex, as are possible combinations andpermutations with the grid. Designs and results can vary with priorities.