Opinions in V2G

Assessing Public Opinions of and Interest in Bidirectional EV Charging Technologies: A U.S. Perspective

Summary

Dean and Kockelman (2023) have conducted a study to 311 American participants (out of 1395 responses) on WTP toward bidirectional EV charging, which contains V2L (Load), V2H (Home), and V2G (Grid). The average WTP values are $280 for V2L and $776 for V2H. 51.3% participants agrees to V2G during grid emergencies with compensation and minimum battery level.

IR (interval regression) was used to study users’ WTP to enable bidirectional charging. It shows that younger users (age <34) have higher WTP to V2L and V2H. OP (ordered probit regression) was used to study the expected frequency of the discharging. It shows that households with more vehicles tend to use it more frequently.

Matt’s Survey

Bidirectional Charging

• V2L means Vehicle to Load. It is an EV built-in technology. The WTP for V2L is a positive number ($280 on average), meaning the users are willing to pay for this feature. It is a feature that can be actively triggered by the user, which benefits the user, not the grid.

• V2H means Vehicle to Home. It is a home energy system equipment that uses the EV battery as energy source. The WTP for V2H is also positive ($776 on average). Similar to V2L, V2H also benefits the user. The reason why V2H is higher than V2L is the cost of buying and installing V2H equipment is more expensive than the V2L feature on the EV.

• V2G means Vehicle to Grid. It is a technology used by the utility to discharge the EVs. Since it decreases the usability of the EVs, and it hurts the battery (as assumed by the study, V2G degrades battery 1% faster), V2G has no benefit to the user, and hence there is no WTP calculated to this feature.

Survey Structure

• Section A: Benefits and prior knowledge of bidirectional charging.
• Section B: WTP of V2L (IR) and expected frequency of using it (OP).
• Section C: WTP of V2H (IR) and expected frequency of using it (OP).
• Section D: Expected frequency of V2G used by the power companies (OP), and user participation of supplier-managed V2G.
• Section E: Expected user participation of V2G in different conditions.

The total number of participants is 1395. Sections A, B and C were mandatory and were answered by 1050. Sections D and E (the V2G part) are optional and were only answered by 311.

Matt’s survey explanation for V2G:

Power companies could use smart charging to interrupt charging when demand for electricity is at or near capacity (to avoid grid blackouts). They could also use bidirectional charging to send power back into the grid (with vehicle-to-grid, V2G) during emergencies.

Assume you primarily drive a battery-electric vehicle (BEV) and have V2G charging capabilities at home. Assume that bidirectional charging degrades your vehicle’s battery 1% faster over the lifespan of the vehicle.

Note: You are compensated $0.70 per mile of range reduced and the power company (“utility”) cannot reduce your range more than 50 miles per emergency.

Would you allow your power company to discharge power from your battery during grid emergencies?

Results

1. Of the 5 V2G participation conditions, the likelihood gradually decreases as condition becomes worse (Figure 1).
2. WTP for V2L (Table 2):
   1. Average value $280.
   2. Lower income users ($30k to $50k) have slightly higher WTP.
   3. Younger users (age <34) have higher WTP.
   4. Those with knowledge of smart charging have higher WTP.
3. WTP for V2H (Table 3):
   1. Average value $776.
   2. High income users ($100k and up) have much higher WTP.
   3. Younger users (age <34) have higher WTP.
   4. Those value importance of bidirectional charging (not only smart charging) have higher WTP.
4. Frequency of relying on V2L (Table 4):
   1. Participants who use more often:
      1. Black
      2. Having more household vehicles
      3. Perceiving importance of smart charging
   2. Participants who use less often:
      1. Older people (age > 55)
      2. Having master’s degree or higher
      3. Having no prior knowledge on bidirectional charging
5. Frequency of relying on V2H (Table 5):
   1. Participants who use more often:
      1. Those with wholesale power prices paid at home
      2. White Hispanic
      3. High household income ($100k to $150k)
      4. Having more household vehicles
   2. Participants who use less often: Older people (age > 65)
6. Frequency of participating in V2G (Table 6):
   1. More participation:
      1. Those with wholesale power prices paid at home
      2. Perceiving importance of bidirectional charging supporting the grid
      3. Perceiving importance of bidirectional charging supporting my home
   2. Less participation:
      1. Female
      2. Older people (age > 55)
      3. Time-of-use (aka time-varying) power price paid at home

Tables and Charts

Figure 1: V2G participation - likelihood to let power company to discharge BEV given a condition

Figure 1: V2G participation - likelihood to let power company to discharge BEV given a condition

Table 1: Summary statistics, where “Original” being V1G, and “Current” being V2L, V2H, and V2G

Table 1: Summary statistics, where “Original” being V1G, and “Current” being V2L, V2H, and V2G

Table 2: WTP for V2L (Interval Regression)

Table 2: WTP for V2L (Interval Regression)

Table 3: WTP for V2H (Interval Regression)

Table 3: WTP for V2H (Interval Regression)

Table 4: Expected reliance on V2L (Ordered Probit Regression)

Table 4: Expected reliance on V2L (Ordered Probit Regression)

Table 5: Expected reliance on V2H (Ordered Probit Regression)

Table 5: Expected reliance on V2H (Ordered Probit Regression)

Table 6: Expected participation in V2G (Ordered Probit Regression)

Table 6: Expected participation in V2G (Ordered Probit Regression)

References

Dean, Matthew D, and Kara M Kockelman. 2023. “Assessing Public Opinions of and Interest in Bidirectional EV Charging Technologies: A U.S. Perspective.” https://www.caee.utexas.edu/prof/kockelman/public_html/TRB24BidirectionalEVTechSurvey.pdf.