ECONOMICS OF ELECTRIC CARS

Keith Hungerford, BSc, BE

Bathurst, 2009

Declaration

• All care has been taken in the preparation of this presentation

• No responsibility will be accepted for any conclusions you draw

Electric car facts and issues

• Electric cars are one solution to “Zero Emission Vehicles” – vehicles that produce no emissions as they drive

• Electric cars can have a zero Carbon Footprint if charged from Green Electricity

• Most major manufacturers have R&D projects under way, some have product in the pipeline

• In Australia only after-market conversions are currently available – both New and Used

• In the UK and USA new electric vehicles are on the market. Not in Australia due to non-compliance with Australian Design Rules.

• Major issues are Range and Cost (inter-related)

Range issue (indicative)

0 100 200 300 400 500

Petrol

Electric(Lead acid)

Electric(Lithium IronPhosphate)

Range (km) / Weight (kg)

Weight of fuel/batterysystem (kg)

Range (km)

Range requirements

• Majority of suburban journeys are reported to be about 5 km – very compatible with electric car capabilities

• Many cars are also used for occasional extended journeys – a major issue for electric cars

• Analysis of economics based on a mix of “Commute” and “Maximum” journeys

Analysis method• Calculation of Electric vehicle costs

including conversion and operation

• 40 assumptions of varying reliability

• Data obtained from Internet – AEVA, ZEVA, etc.

• Discounted cash flow analysis of comparable Petrol and Electric vehicles

• Specific travel model – mostly commuting with some longer weekend journeys

Lead Acid economic break even, 50 km Max

0

200

400

600

800

1000

1200

1400

1600

1800

0 1 2 3 4 5

Petrol $/L

Ba

tte

ry $

/kw

h

10 km commute20 km commute40 km commute

Lithium Ion economic break even, 45 km Commute

0

200

400

600

800

1000

1200

1400

1600

1800

2000

0 1 2 3 4

Petrol $/L

Bat

tery

$/k

wh

60 km Max100 km Max200 km Max

Assumptions 1Vehicle Mass assumptions

Vehicle gross mass 1530 kg

Vehicle bare mass 907 kg

Required payload 200 kg

Motor, controller, gearbox, battery box, charger, ancillaries 80 kg

Battery assumptions

Battery energy density 10.5 kg/KWh

Recharge cycles at discharge depth 1 3000

Discharge depth 1 (commute journey) 70%

Recharge cycles at discharge depth 2 2000

Discharge depth 2 (max journey) 80%

Battery cost $619 $ per KWh

Battery charger efficiency 70%Stored =x% of

supplied

Assumptions 2

Vehicle energy use assumptions

Vehicle width 1.65 m

Vehicle height 1.5 m

Drag coefficient Cd 0.3

Rolling resistance coefficient Crr (ZEVA web site) 0.01

Rolling resistance formula (ZEVA web site) Prr = v Crr G M

Aerodyamic drag formula (ZEVA web site) Pd = 0.5 *1.2 Cd A v^3

Kinetic energy formula Ek = 0.5*M v^2

Gravitational energy formula Eg = MhG

Loading for other factors 20%

Assumptions 3

Journey assumptions

Max vehicle speed 80 km/h

Max elevation range 200 m

Commute distance 45 km

Average commute speed 60 km/h

Commute days per year 230 days

Commute journeys per day 1 journey/day

Max driving distance 200 km

Speed during max distance 80 km/h

Max distance days per year 50 days

Assumptions 4Conversion cost assumptions

Cost of electric motor, controller, battery box and ancillaries $3,000

Cost of labour to perform conversion $3,000

Fuel cost assumptions

Cost of electricity $0.16 $ per KWh

Cost of petrol $4.00 $ per Litre

Petrol vehicle consumption data

Fuel consumption 7 L per 100 km

Engine service interval 10,000 km

Cost of service $200

Initial purchase price $15,000

Financial assumptions

Discount rate for money 7% per annum

Escalation rate of Petrol and service costs 7% per annum

Escalation rate of Electricity costs 7% per annum

Basic model result summary

Basic electric car summary

Battery mass 338 kg

Required battery capacity 32 kWh

Battery cost $19,963

Total conversion cost $25,963

Total annual distance 20,350 km

Expected battery lifetime 9.8 Years

Cost of recharge energy per km $0.028 $ / km

Simple cost of battery per km $0.100 $ / km

Driving cost, recharge energy + battery $0.128 $ / km

Petrol car driving cost $0.125 $ / km

Discounted cash flow analysisItem/ Year No. 0 1 2 3 20

Basic car purchase $15,000

Fuel and services $3,256 $3,256 $3,256 $3,256 $3,256

Total Discounted to Year 0 $18,256 $3,043 $2,844 $2,658 $841

Nett Present Value (Cost) $52,750

Nett Present Value 10 yr (Cost) $39,470

Electric Car

Basic car purchase $15,000

Electric Conversion $21,603

Recharge energy cost $709 $709 $709 $709 $709

Total Discounted to Year 0 $37,312 $662 $619 $578 $183

Nett Present Value (Cost) $52,750

Nett Present Value 10 yr (Cost) $41,928

Ratio of Electric to Petrol cost 1

Ratio of Electric to Petrol cost (10 yr) 1.062

Things to consider

• Expect fuel prices to rise over time (model inflates them at eg 7% pa)

• Expect battery prices to fall over time (model has them constant)

• New off-the-shelf electric cars will become available in the next year or two, and get better as the industry matures

• In Australia new and second hand conversions are available now

More things to consider

• Electric cars are now cost effective for specific journey patterns

• If recharge at both ends of the daily journey (eg at Home and at Work) halves the commute range and improves economics

• Max journey (non-commute journey) dominates design requirement and costs

Sustainability

• Zero carbon emissions if charged from renewable energy

• Long life, low maintenance motor may reduce significance of energy embedded in the vehicle structure

• Battery elements should all be recyclable (needs recycling program)

Ancillaries on retrofit vehicles

• Power steering – choose base vehicle with electric power steering

• Brake booster - ? Petrol vehicles use inlet manifold vacuum, not available in electric

• Air conditioning – power hungry, continuous rotation needed

• On board battery charging

Primary features

• LiFePO4 (LFP) batteries now give best performance/economy mix

• Lead Acid batteries OK for short range use (heavy, low energy per kg and limited life)

• AC motor superior to DC and provides regenerative braking for more range in hilly country or city driving, but more expensive

• High battery voltage requires proper safety installation

Competitors

• Plug-in Hybrids – use electric grid energy for short journeys, petrol for longer ones

• Compressed air cars – need to be purpose built structure, range TBD

• Hydrogen/fuel cell – doubtful at present, most H2 production now fossil based

• Cycling with or without electric assist a good alternative for short journeys and more healthy

Where to buy?

• Australian Electric Vehicle Association – see their web site www.aeva.org.au/links

• Zero Emission Vehicles Australia – see their web site www.zeva.com.au/links

• Blade Electric Vehicles (converted new Hyundai Getz www.bev.com.au

• Mitsubishi iMiEV http://www.mitsubishi-motors.com/special/ev/whatis/index.html

Conclusions

• This technology is available now and is cost effective for some journey patterns

• Two (or more) car families are more likely to obtain good economics

• Expect continuing improvements and expansion of the cost effective journey patterns

Mini Minor conversion

For more photos and information on this conversion visit www.killawatt-electric-car-conversions.com