Argonne’s Science at Work webinar comparing EVs with conventional vehicles

For more details, check out the following materials:

• Free GREET model
• Introductory GREET presentation
• Article “Regional Emissions Analysis of Light-Duty Battery Electric Vehicles”

Argonne National Laboratory

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Answers to questions asked during the webinar

1. What type of crude oil is used for the comparison? Different crude oils have different refining needs.
   • Answer: Indeed, oil source matters since it can affect API gravity, sulfur content, transportation distances (and transit method), etc. The GREET model considers crude from multiple global sources including the United States, Canada (oil sands and conventional), Mexico, the Middle East, Latin America, and Africa. We also account for a portion of ethanol within the fuel consistent with U.S. average conditions.

2. How many miles are you assuming in your life cycle emissions?
   • Answer: Lifetime miles are based on average vehicle driving distance by vintage and survivability from the VISION model. For midsize cars in the U.S., this is 173,151 lifetime miles. Note that mileage serves to amortize the vehicle production burdens but does not impact the Fuel Cycle.

3. I assume Natural Gas in this chart is just fossil. It does not include Renewable Natural Gas.
   • Answer: Yes, the chart only shows average natural gas in the U.S. We could also provide RNG.

4. For electricity production, are the GHG emissions just associated at the power plant?
   • Answer: No, this is life cycle, thus it includes all aspects of fuel production and consumption. So, for this, and for every other fuel or material, this goes all the way back to extraction from earth and includes all processes used to provide a usable form of the fuel/material.

5. Does this model also work for MD and HD commercial vehicles?
   • Answer: Yes, GREET also has well-to-wheel (WTW) results for many diverse MHDV, and further has the vehicle cycle for Class 6 Pickup and Delivery, and Class 8 Sleeper- and Day-cab MDHV, thus we have cradle-to-grave results for those 3 classes (multiple powertrains).

6. Can you provide a similar analysis for resource depletion and mining waste during manufacturing, comparing BEVs to ICEVs?
   • Answer: GREET does not currently have resource depletion analyses.

7. Can you comment on resource depletion and the effect of battery recycling?
   • Answer: GREET does not currently have resource depletion analyses. But the effect of battery recycling would be to reduce the rate at which resources are depleted.

8. I’d be interested in seeing a GREET comparison with a conventional vehicle getting 50 mpg.
   • Answer: My back-of-the-envelope analysis indicates that improving the gasoline vehicle from 31 to 50 MPGGE (Miles per Gallon of Gasoline Equivalent) would reduce the life cycle GHG emissions to 275 g CO2e/mile (Grams CO2 Equivalent per Mile).

9. How would a Hybrid compare with an EV?
   • Answer: A comparable hybrid would achieve ~46 MPGGE, so it would be slightly worse than the 50 MPGGE results noted above, but it would also have a battery, motor, generator, and electronic controller, which would add slightly to the vehicle cycle, but not nearly as much as the battery for the EV.

10. Can you provide a similar analysis for all air-pollution (not just GHG, but including PM2.5, NOX, SOX, etc.)
    • Answer: We have such capabilities with the GREET model.

11. I’d love to see a future seminar when the comparison is a Full Hybrid, PHEV and EV. I think everyone accepts the results for conventional ICE.
    • Answer: The link below provides a detailed current and future analysis for small SUVs of the noted powertrains along with FCEVs, and considers some future CO₂ reduction fueling pathways. https://www.hydrogen.energy.gov/pdfs/21003-life-cycle-ghg-emissions-small-suvs.pdf

12. Looking at the EV split on the last slide, I didn’t see any upstream emissions. Does this model also include the GHG emissions for production and maintenance of the different types of facilities and the overall life expectancy?
    • Answer: I believe the question is mistaken, the EVs only have upstream, but no tailpipe emissions. From the frame of the vehicle, all electricity emissions are upstream. We account for all emissions associated with fuel production and energy generation. We do not, in our baseline configuration, account for the construction and maintenance of infrastructure as this is amortized over a very large quantity of delivered product (electricity in this case) and is thus very small.

13. How would this comparison look for an HEV or PHEV?
    • Answer: See https://www.hydrogen.energy.gov/pdfs/21003-life-cycle-ghg-emissions-small-suvs.pdf

14. How much energy is consumed recycling batteries?
    • Answer: That can be considered using Argonne’s EverBatt model. Within this analysis we use a conservative approach and assume that no recycling credits are provided for recycled batteries. https://www.anl.gov/egs/everbatt

15. What does the landscape for recycling discharged EV vehicles look like?
    • Answer: This is outside the scope of this presentation, but Argonne’s ReCell Center (https://recellcenter.org/) is actively looking at advanced EV battery recycling approaches.

16. How hard is it to swap the batteries in EVs?
    • Answer: This is beyond the scope of my analyses. But it has not yet been profitably achieved on a broad scale for EVs. This is more of a vehicle design issue coupled with a planning and logistics challenge than an LCA issue.

17. How do you model environment impact of the increased competition for rare minerals with demand increasing and quality of ore decreasing?
    • Answer: For the GREET model, we use the best available public data to determine the energy and material input needs of all materials, this is typically static or retrospective in nature. However, as noted, increased demand for materials will place a pressure on global ores with the likely effect of lower ores grades. Such dynamic elements are not included for materials within GREET at present. The general observation, however, is that as ore grade decreases the amount of energy required per tonne of final material should increase (all other conditions being equal).