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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