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Environmental footprint of electric vehiclesMarco Miotti
Jessika E. Trancik
Tokyo
April 17th 2019
Personal vehicles and greenhouse gas emissions
2
of global GHG emissions
IEA 2012, EPA 2015
13%
Fuel useSupply chains
Personal vehicles contribute substantially to total emissions
Personal vehicles and greenhouse gas emissions
3
of global GHG emissions
23%
of U.S. GHG emissions
IEA 2012, EPA 2015
13%
Fuel useSupply chains
Personal vehicles contribute substantially to total emissions
Technological alternatives exist to reduce emissions
4
But what is their emissions reduction potential, and what does it depend on?
Greenhouse gas emissions vs air pollutant emissions
5
Greenhouse gas emissions(CO2, CH4, ...)
Radiative forcing
Climate change
Greenhouse gas emissions vs air pollutant emissions
6
Greenhouse gas emissions(CO2, CH4, ...)
Radiative forcing
Climate changeHuman health
Soil qualityWater quality
Pollutant concentration in air
Air pollutant emissions(Particulate matter, NOx, SOx, ...)
Greenhouse gas emissions vs air pollutant emissions
7
Greenhouse gas emissions(CO2, CH4, ...)
Radiative forcing
Climate change
Air pollutant emissions(Particulate matter, NOx, SOx, ...)
Human healthSoil quality
Water quality
Pollutant concentration in air
Global issue Regional issue
Lifecycle perspective for evaluating emissions
8
Fuel feedstockCrude oil extraction,
natural gas extraction
Fuel productionOil refining, electricity, ...
Fuel useCombustion
Lifecycle perspective for evaluating emissions
9
Material extractionIron, oil, lithium, cobalt, ...
Component productionChassis, engine, seats, ...
Fuel feedstockCrude oil extraction,
natural gas extraction
Fuel productionOil refining, electricity, ...
Fuel useCombustion
End of lifeDisposal, recycling
Lifecycle perspective for evaluating emissions
10
Material extractionIron, oil, lithium, cobalt, ...
Component productionChassis, engine, seats, ...
Fuel feedstockCrude oil extraction,
natural gas extraction
Fuel productionOil refining, electricity, ...
Fuel useCombustion
End of lifeDisposal, recycling
Unit: gCO2eq/km
Three key challenges to evaluating emissions
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Uncertainties in emission accounting
1
Three key challenges to evaluating emissions
12
Uncertainties in emission accounting
1
Dependence on regional conditions
2
Three key challenges to evaluating emissions
13
Uncertainties in emission accounting
1
Dependence on regional conditions
2
High diversity of technologies and vehicle models
3
Emissions of personal vehicles under average conditions
14
U.S. average conditions251,000 km lifetime distanceU.S. average electricity mixHydrogen from reformed methane
Electric vehicles reduce emissions by 50%, fuel cell vehicles by 40%
Based on: Miotti, Supran, Kim, and Trancik, ES&T (2016).
Lithium-ion battery and fuel cell stack production
15
Batteries and fuel cells only contribute a few % to total emissions
Based on: Miotti, Supran, Kim, and Trancik, ES&T (2016).
Uncertain battery emission
16
Even under pessimistic assumptions, electric vehicles perform well
Based on: Miotti, Supran, Kim, and Trancik, ES&T (2016).
Sensitivity of emissions to fuel production pathways
17
Diversity in fuel production pathways (including electricity) has major impact
Based on: Miotti, Supran, Kim, and Trancik, ES&T (2016).
Regional conditions matter
18
Emission reduction of electric vehicles depend on where they are driven
Difference in emissions:kgCO2eq/year
Electricity mixAffects emissions for charging EVs
Regional conditions matter
19
Emission reduction of electric vehicles depend on where they are driven
Difference in emissions:kgCO2eq/year
Electricity mixAffects emissions for charging EVs
Local climateAffects fuel economy
Regional conditions matter
20
Emission reduction of electric vehicles depend on where they are driven
Difference in emissions:kgCO2eq/year
Electricity mixAffects emissions for charging EVs
Local climateAffects fuel economy
Trip distance and speed distributionAffects fuel economy
Regional conditions matter
21
Emission reduction of electric vehicles depend on where they are driven
Difference in emissions:kgCO2eq/year
Electricity mixAffects emissions for charging EVs
Local climateAffects fuel economy
Trip distance and speed distributionAffects fuel economy
Annual miles traveledAffects impact of production emissions and cumulative annual emission reductions
Carboncounter.com
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An interactive tool for consumers to explore emissions and costs of cars
Summary
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Battery electric vehicles reduce greenhouse gas emissions by almost 50% on average compared to conventional gasoline vehicles.
1
Summary
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Battery electric vehicles reduce greenhouse gas emissions by almost 50% on average compared to conventional gasoline vehicles.
1
Emission reductions of electric vehicles strongly depend on electricity mix and regional conditions.
2
Summary
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Battery electric vehicles reduce greenhouse gas emissions by almost 50% on average compared to conventional gasoline vehicles.
1
Emission reductions of electric vehicles strongly depend on electricity mix and regional conditions.
2
Tools that provide information to consumers are important and can impact consumer preferences.
3
The environmental impacts of electric vehicles havebeenmuch debated. This work shows how importantit is to tease out the different contributing factors,such as travel behaviors and energy infrastructure.Only by understanding these factors can weaccurately assess the benefits of vehicleelectrification, and how these benefits change overtime and space. And, in this way, the research caninform decisions at diverse scales, from nations tocities, and even individual consumers. A similarapproach can be applied to understanding theimpacts of many other technologies.
A message from Professor Jessika Trancik
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Thank youContact: Jessika E. Trancik | [email protected] | trancik.mit.edu
Visit: www.carboncounter.com
